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IS : 1859 ( Part I ) 1876I ndian St andard

GLOSSARY OF TERMSRELATING TO IRON AND STEEL

PART I GENERAL METALLURGY, HEAT TREATMENTAND TESTING

( First RevisionSecond Reprint AUGUST 1990

UDC 0014 : 669 : 621785 : 6201

0 Copyrfghr 1976BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH WFAR MAR0

NEW DELHI 110002Gr 10 .*.December 1976

( Reaffirmed 2003 )

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ISr1956(PartI)-1976YI ndian Standard

GLOSSARY OF TERMSRELATING TO IRON AND STEEL

PAUT I GENERAL METALLURGY, HEAT TREATMENTAND TESTBNGF irst Revision )

Metal Standards Sectionalommittee, SMDC 1tasimaa Rrprrnrting

SHUA. IL BstATrAtmAaYYA IaillistryafRailwaysMmbnJam-(Y C) Albmawto1 Dmmmx (MS ) Ski A. K.snmt Y. A&tawLtr > BhattachyyyahIi&gan~Allud Machinery Corporation Ltd,Snu N. V. &~~~AVAN b )DUA.S.W National Tat House, CalcuttasHmD.D.Bmnvua Indian Tube Co Ltd. J amshcdpur-O.N.Asuwu.(duIldr)

-&5~- The Tata Iran & Steel Co Ltd. J amhdpur-G.&n -m(U)SamK.c.~(d&mu&)Hindurtrrn steel Ltd, Ran&i

-P-K. Ck#hv Ministry ofDcfcnce ( DGI )-K.V.~A- N. S. CDA~~ +T International Nickel ( India ) Pvt Ltd, BombayInstntmcntation Ltd, KotaSnuJ .S.snY(I~)SaruB.N.11~~ National MctalhrgicaI.IUi&~~~cc (R&D )

Laboratory ( CSIR ),Saar N. T. G-anSntA.K. GUEA Directorate General &Supplies 8 Dispo& ( IIlspcc-tionWing),NcwDclhiSFIRt . c. MusTArr (&uae&)DRs.s. KEAteNASERXA.N.RAO(~&~I&) Heavy Enginteuhg Corporation Ltd, RanchiDRD.M.LAUXtMlSmttT.K.Dmn(Ahtuk) Indian Iron B Steel Co Ltd, Bumpur

( Conhnucd n pagr 2 )

BUREAU OF INDIAN. STANDARDSThis pttbkation is M w the I&a Copvrighf Ad ( XIV of 1957 ) andreprodtion in wbolc or in put by py -except with written permission of the$4abhh~shll kdecmedtobe8ntd _ t of copyright under the said Act.

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IS: 1956(Part I)-1976.(Continudfrom pagt 1 )M embers mJf-t

SHRI U. MOHAN RAOSARI B. K. MIJRT~ Bharat Heavy E~ectricala ( India ) Ltd, BhopalIndian Aluminium Co Ltd, CalcuttaSHRIN.GOPALKRISHNAN( Ahmate)SHRI S. K. OH~IDR S. R. PRA~ANI~ Bharat Heavy Electrieals Ltd. H+wySRRI M. K. RAO Ministry of Steel and Heavy EnsureuylThe Binani Metal Worka Ltd. Calcutta s~a1A.K. GIiATTRRJEE(dbRd6)SHIU S. ROY Indian Non-Ferrous Metals Manuf~cturcrs Asocia-tion, Calcutta

SHRI A. K. BASIJ Akmate )SHRI V. K. WAZ~R Institute of Indian Foundrymen, CalcuttaHON SECRETARY( Rltnna~ )SHRI C. R. RAMA RAO, Director General, IS1 ( Z2r-oficio M~lnbcr )Director ( Strut & Met )

Secreta~SHRI VIJ AY KIJ MARAssistant Director ( Metals), IS1

Subcommittee for Terminology, Classification and Designation ofSteels, SMDC 1:CVfW?l~

SHRi K.V. INNAPPA International Niekel ( India ) Pvt Ltd, BornbayM embers

SHRI R. M. BALANX Dircrl~te General of Teehnieal Development, NewSHRI B. G. BAWVRAJ MysorE Iron & Steel Ltd, BbadravatiSHR~ K. B. D. BE-R (AI@& )SHRXS. K. BASU Guest, Keen, Williams Ltd, HowrahSHRI D. D. BAUPTANI Indian Tube Co Ltd. JamshedpurSHRf P. K. t%AKRAVMTY The Tata I ron & Steel Co Ltd, JamshedpurSH~I M. C. K~MARAEVVAM~ Abm& )StmxP.K. CHATTSRJEE hfiniitry f Defence ( DGI )CIiJ3MISTND hfETALLURGm MiDistry of RailwaysSHRX M. K. DUTCA Hindwan Steel Ltd, DwgapurSHRIR. &lTA Indian Iron Steel Co Ltd, BumpurSHIUT. K. DIJ TTA ( Albma& )SHRI S. K. GHOU~AL Central Board of Excise and Customs ( Ministry ofFinance ), New DelhiSHRI A. K. GUHA Directorate General of Supplies and Dir-(Inspection Wing ), New DelhiSHRIP. C. MXJ STAR ( AltemutrSHRI R. M. KR~AN Iron & Steel Control, CalcuttaDR V. RAMASWAMY R;;w-~~ Development, Hindustao Steel Ltd,

SHRI S. R. MEDlMlTA ( AkrnakSHRX M. M. SHENOY Hinc$utan Steel Ltd, CalcuttaEzzwU _ e Steel (3 Ltd, Bombay8z cd Ordnance FaCtOIIcl ( h%niSw OfD&xc ), Calcutta

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IS : 1956 ( Part I ) - 1976I ndi an St andard

GLOSSARY OF TERMSRELATING TO IRON AND STEEL

PART I GENERAL METALLURGY, HEAT TREATMENTAND TESTING( Fi rst Rev i si on0. FOREWORD

0.1 This Indian Standard ( First Revision ) was adopted by the Indian&axxlards Institution on 11 May 1976, after the draft finalized by the MetalStandards Sectional Committee had been approved by the Structuraland Metals Division Council.02 This standard was ilrst published in 1962. As a result of experiencegained during these years, certain modifications have been made in some ofthe meanings of the various terms. The Sectional Committee while issuingt.& revision felt it desirable to issue the standard in separate parts. Otherparts in the series are as follows:

Part IIPart IIIPart IVPart vPart VIPart VIIPart VIII

Steel makingHot rolled steel products ( excluding sheet and stri& h:.Steel sheet and strip .a. .,B,right steel bar and steel wireForging ( including drop forging )Wrought ironSteel tubes and pipes

0.3 This standard has been prepared for the guidance of the mamrkturersand the users to assist them in the uniform interpretation of the commonterms used in the iron and steel industry.

1.SCOPE1.1 This standard ( Part I ) covers terms commonly used in the field ofgeneral metallurgy, heat treatment and testing.

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ISr1956(PartI)-19762. DEFINITIONS2.1 Acid Proctss - A steel making process in which steel is refined underan acid slag in an acid refractory lined furnace or convertor.2.2 Add SteeI - Steel made by acid process.23 ~-Achangeinpropertieswhichmayoccur~~withtimat atmospheric temperatures ( natural ageing ) and more rapidly atelevated temperatures ( artificial or accelerated ageing ).

Artificial ageing l.cfim to:a) Qpnch Agdng Ageing following quenching ( JW alro 2.296 ), andb) Strain Aping Ageing induced by cold-working.

2.4 w - Hardening due to ageing ( w 26 ).25 ~-Hardening by cooling in air or gas at ambienttemperatme f&u a temperature above the transformation range.2.6~Harda~@~(~~Stecl)-Asteelwhichres-ponds to air-hardening treatment.2.7AirTest(PresmreTm) -A test for leakage of a hollow produetby subjecting it to a specifkd air pressure.2.~ Auatropy (Polym~) - The reversible phenomenon bywhich certain metals may exist in more than one crystal structure. If notreversible, the phenomenon is termed poIpox h .2.9 Allay - A substance having metallic properties coksting of two ormore elements in which the major constituent is a metal, or of mtallicand non-metallic elements which are miscible with each other when molten,and have not separated into distinct layers when solid.2.16 ARoy Ekmm - An element ( metal or non-metal ) added deli-berately to a metal to modify its mechanical and/or physical properk.2.11 AIloy SteeI - A steel containing one or more alloying elements as aresult of which it develops specific characteristics ( for detailed de&it&nsee IS : 75981974+ ).2.12 AI* Iron -The body-centred cubic form of iron which in pureiron is stable below 91OC.2.13 AMepling- Heating to and holding at a suitable temperature,followed by cooling at a suitable rate, for inducing softness. It may alsobe used for the following other purposes such as:

a) Improving machinability,*Classification of steel.

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I6:19 6(PartI)-1976b) Improving cold-working properties,c) Obtaining a desired structure,d) Reducing stresses, ande) To facilitate dil%tsion processes.

When applicable, the more specific terms, such as full annealing,isothermal annealing or sub-critical annealing, etc, should be used.Full Antualing Heating to and holding at some temperature abovethe transformation range, followed by cooling slowly through the transfor-mation range. The exception is in the case of austenitic steels which arequenched rapidly from the homogenizing temperature for softening thematerial.IsothertnuLAnnealing Heating to and holding at some temperatureabove the transformation range, then cooling to and holding at a suitabletemperature below the transformation range until the austenit*to-pearlite transformation is complete, and finally cooling in air.ProcessAnnealing In the sheet and wire industries, heating a ferrousalloy to a temperature close to, but below, the lower limit of the transfor-mation range and. then cooling, in or&r to soften the alloy for furthercold-working.Sub-criticalAnncal& -Heating to and holding at some temperaturebelow the transformation range, followed by cooling at a suitable rate.UnirizGdAanealiag- See 2.264.

2.14 Arrest Paint - The point at which an otherwise continuous cooling orheating curve of a metal or alloy shows a discontinuity or break. It occursat a temperature at which a phase change takes place in the metal or alloyand results from the absorption or evolution of heat during heating or coolingrespectkly ( see Fig. 1 ).2.15 AC Point - An arrest point on heating ( see 2.14 ).2.16 AT P&t-An arrest point occurring on cooling ( see 2.14 ).2.17 Aruforming - Cold-forming of metastable austenite in alloy steeland subsequent cooling in air or oil resulting in the formation of bainite,martensite, etc. This treatment is employed for improved strength.2.16 Aostunpcrkrg- Isothermal sub-critical transformation of austeniteat temperatures below that at which pearlite is produced and above that atwhich martensite is formed.2.19 hmemitt -A solid solution of carbon and/or alloying elements ingamma iron which has a face centred cubic crystal structure.

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IS:1956(PartI)-19762.20 Alrstenite Grain Size or Austdtic Grain Size - The size of aus-tenite grains developed when steel is heated above the critical ( or trans-formation ) range under specified conditions. The grain coarsening ten-dency of a steel is determined by measuring the austenitic grain size understandard conditions.2.21 Austmitic Steel - A steel, generally non-magnetic, containingsufficient proportions of alloying elements ( for example, nickel, chromiumand/or manganese, etc ) to render it predominantly austenitic at atmos-pheric temperatures.2.22 Austenitising-Heating steel to a temperature above the criticalrange, to render the steel wholly austenitic ( see Fig. 2 ).2.23 Bainitt - The constituent produced when austenite transforms at atemperature below that at which pearlite is produced and above that atwhich martensite is formed.2.24 Baking ( Staving ) - Heating after pickling to remove hydrogen.2.25 Banded StructusW - A segregated structure of nearly parallel bandsrunning in the direction of rolling or forging, which is revealed by etchingthe polished surface.2.26 Basic Proctss -A steel making process in which steel is refinedunder a basic slag in a basic refractory lined furnace or convertor.23 Basic Steel - Steel made by the basic process.2.28 Bend Test - A test for ductility and soundness. It is carried out bybending a test piece at the middle, over a specified radius generally by asteadily applied load or by blow. Three kinds of bend tests are used inpractice, namely:a>

b)Cl

Single endest wherein the test piece is bent once according tothe specified angle and radius of bend ( see IS : 1599-1974* );CloseBend Test wherein the test piece is bent through an angle of180 and the two arms are folded flat on each other; andRever se Bend l est wherein the test piece is 6rst bent through anangle of 90 and then the bend is opened out so that the piece revertsto its original position. in some cases the piece is bent throughan angle of 180 and then brought back to its original straightcondition. The bending1 in both cases, is then continued countingthe number of reverses, till the piece fractures. (This test is usedfor sheet, strip and wire. ) (see IS: 1716-1971t).

*Met&d for bend test for steelproducu other than sheet, strip, wire and tube (firstm&ion .tMethod for reverse bendtestingof ateelwire (/irstrmicia, .

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10M~cxP~~~EN1AGe

0.05950 &lo900850000h07so

700650600550500450

4OoFw 0.015 0.025WEIGH7 PERCENlAGE

CARBON- Fe-C EQUILIBRIUM

IEXPERIMENTAL- Fe-F+ EQUILI8RIUM

(EXPERIMENTALI

AIMIC PERCENTAGE CARBON

1580 1 2 3

15601540ls201500148014607440142014001380

1360 Fe GO5 0.01 0.15 0.2 0. 25 0.3 0.35 0.4 0.45 0.5 0 . 66 065 0.7 0.75

FIG.2 IRON-CARBON.

WEIGHT PERCENTAGE CARBON

EQUILIBFUUYIAGRAM

vILH

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I 3:1956(PartI)-19762.29 Bessemer Process ( Henry Bessemer Process ) - A steel makingprocess in which pig iron is refined in an +d refractory lined convertor byblowing air or a mixture of air, carbon dioxide and oxygen or steam throughthe molten metal. The basic process is known as Thomas process.2.30 Bessemer Steel-Steel made by the Bessemer process.2.31 Black Annealing - Annealing without any protective medium.2.32 Blackheart Malleable Cast Iron - White cast iron rendered mal-leable by suitable annealing using inert atmosphere to prevent appreciabledecarburization, in order that the carbide is decomposed into graphiticcarbon and ferrite. The temper carbon, as it is called, is distributed in theform of nodules, unlike the flaky graphite. The fracture shows a dark greycore from which it derives its name ( see IS : 2 108-1962* ).2.33 Blank Carburizing - A test applied to carburizing steels for deter-mining the core properties.2.34 Blank Nitriding - The thermal treatment associated with nitriding,as applied to a test piece without the nitriding medium.2.35 Blast Farnace -A vertical shaft furnace where a large volume ofair blast is used for smelting iron ore, with coke or charcoal with suitablefluxes, into pig iron.2.36 Blasting - A process of cleaning or preparing surfaces by high speedimpact of abrasive particles, such as sand, chilled iron shot, or angularsteel grit ( generally called sand blasting, shot blasting or grit blasting ).2.37 Blister ( Pin-Head Blister ) - Local separation of a layer of steelcausing a protuberance on the surface, underneath which is a cavity.2.38 Blow Holes - Cavities in iron or steel castings formed by entrappedgas bubbles during solidification.2.39 Blue Annealing ( Blueing ) - Sub-critical annealing of steel, duringwhich the surface is oxidized to a blue colour by controlled amount of air/steam permitted into the annealing chamber.2.49 Blue Brittleness - Brittleness occurring in steel when worked in thetemperature range of approximately 200 to 4oOC, or when cold after beingworked within this temperature range.2.41 Blueing - Heating in a suitable atmosphere for imparting a bluecolour to bright steel ( see also 2.39 ).

YQmifkation or blackhcartmalleableron cdngs.9

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2.42 Bottom Casting (Uphill CaSting ) -Simultaneous castingof anumber. of ingots by pouring the molten metal into a central refractory-lined tube or trumpet, whence it flows through ret&tory runners into thebottom of the moulds.2.43 Bapadpry Film-grain boundaries. A thin envelope of a constituent deposited at the2&p_b5_ ( Qoaa. Annea&g)-Annealingcarried out in aminimize oxidation.2.45 Bra&ing Strut@ - Breaking load at the time of rracture dividedby the original cross-sectional area of the test piece ( sodFig. 3 ).2.4 Bright hmdhg - Annealing under controlled atmosphere (neu-tral or reducing gas ) to prevent oxidation of the surfsce and to preserve itsbrightness.2.47 BrinaU Hardness Test-An indentation carried out by pressinga hard steel ball of known diameter, under a standard load, against thesurf&e of a material, and then measuring the diameter of indentationproduced ( see IS : 1500-1968* ). The result of the test is expressed asBrinell hardness number ( HB ).

HB= Load in kgSpherical area of the impression in nuna2.48 Brittle Pramare (Crystalline Fracture) -A fracture withoutany visible or appreciable plastic deformation.2.49 Brittkneaa- Tendency to fracture without any visible sign ofappreciable deformation.2.50 &it& Transition Tempcrrrtprc -See 2.424.2.~1 &uning- Heating to such a high temperature that the proper&sof the material are permanently impaired by incipient fusion or oxide pene-tration.2.52 Garbo-Nitriding - Surface treatment through the introduction ofcarbon and nitrogen simultaneously ( SM aZso .55 and 2.57 ).2.53 Carbon Steel - An unalloyed steel ( see IS : 75981974t ) .2.54 Carburizing ( Case-Carbdhg ) -A process of introducing car-bon into tllc surkc of a solid piece of steel by heating and holding abovethe transformation temperature in contact with a suitable source ofcarbonwhich may bc a solid, liquid or gas.

*Method for Brine11 hardness test for steel (fist ra&im ).tCla&ication of steel.

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IS: 1956 Part I -19762.55 Case The surfa ce la yer which ha s been ha rdened by cha nging t hecomposit ion or by hea t t rea tment or a combina t ion of both .2.56 Case-Carburizing See2.54.2.57 Case-Hardening Ha rdening t he surfa ce by cha nging it s composi-t ion follow ed by, if necessa ry, suit a ble hea t t rea tment .

NOTE 1 The term is usually applied to earburizing or cyaniding treatment with orwithqut further heat treatment for grain refinement followed by quenehkg to producea hard case and a core of suitable propertiesOT 2 Nltriding is one of the methods of case hardening

NOTE 3 Flame and induction hardening are not included in this definition2.5S Cast Heat or Melt Usua lly the product of a single furna cecha rge. Somet imes t he furna ce content s a re t a pped into tw o or more la dleswhen the product of ea ch la dle ma y be ca lled a sepa ra t e ca st .2.59 Casting P ouring or t eeming molten meta l in t o moulds. Thisa lso refers t o meta l object s so produced.2.60 Cast Iron An a lloy essent ia lly of iron a nd ca rbon cont a ining moretha n 2 percen t ca rbon usua lly betw een 2-5 a nd 4 percent . I t so con-t ains silicon, ma nga nese, sulphur a nd phosphorus in va rying amounts.The cha ra ct er of ca st iron is cont rolled by t he ma nner in which ca rbon ispresent , a nd t he fra ctured surfa ce of ca st iron exhibit s cha ra ct er ist ic colour ,namely, whit e, mot t le, or grey see Fig. 4 , depending on whether ca rbonis present wholly in combined st a te a s ca rbide or pa rt ly in combined st a teor wholly in the form of gra phit e.2*61 Cast Steel The t erm is used for st eel ca st ings,2.62 Caustic Cracking Caustic Embrittlement Intercrystall inecra cking in mild st eel due t o t he combined effect of st ress corrosion in a lka linemedia.2.63 Cellular Structure Network Structure A st ructure in w hichthe const it uent is present a s a netw ork surrounding t he cryst a l gra ins. Forexa mple, ca st iron ha s such a st ructure.2.64 Cementite A compound of iron a nd ca rbon, known chemica llya s iron ca rbide a nd ha ving t he a p roxima te formula Fe8C . I t is cha ra c-rer ized by a n orthorhombic cryst a st ructure. When it occurs a s a pha sein st eel, t he chemica l composit ion w ill be a lt ered by the presence ofma nga nese a nd other ca rbide forming element s.2.65 Cha rpy Impa ct Test A pendulum t ype single blow impa ct t estin which a specimen usua lly not ched is support ed a t both ends a s a simplebeam and broken by a fa lling pendulum on the fa ce opposit e t o a nd imme-dia t ely behind the not ch. The energy a bsorbed a s det ermintxi by t he

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IS 31956 Part 1.) 1976

FIG. 4 SIIRFACE OF CAST IRON FRACTUREsubsequent rise of pendulum, is a mcasurc of impact strength or notchtoughness and is cxprcasecl in joules ( see IS : 1499-1959* ).2.66 Chill Crystals -A thin skin of small crystals formed by rapidfreezing of molten metal in contact with a cold surface ( see Fig. 5 ).2.67 Chill Cast - Cast against a mold which has heat extracting pro-perties.2.66 Clad Steel-A composite material obtained by firmly boundingtogether a carbon or alloy steel with a surface layer of nother steel, .metalor alloy.2.69 Cleavage Fracture ( Crystalline Fracture ) - Fracture alongcleavage planes. Such fractures show bright facets and are characterized bylittle plastic deformation.2.76 Cleavage Plane - Planes of easy fracture related to the crystal struc-ture. They arc not necessarily rclatcd to the boundaries of the crystal andare found in both minerals and metals.~__~ -

*Method for charpy impact test ( U-notch ) for steel.13

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IS:1956(PartI)-1976

FIG. 5 INGOT SECTIONSHOWING RYSTALLINEARRANGEMENT2.71 Close Annealing - See 2.44.2.72 Coalescence - Formation of bigger aggregates due to the merger ofsmaller ones.2.73 Cold Shortness - Lack of ductility at atmospheric temperatures.2.74 Cold-Working - Substantial mechanica working ( usually above5 percent), for example, drawing, rolling, forging, etc, of a metal or ahoybelow its normal recrystallization temperature.2.75 Columnar Crystal - The crystals growing generally normal to thecooling surface during solidification ( see Fig. 5 ).2.76 Combined Carbon.- Carbon present in chemical combination withiron or other alloying elements.2.77 Compression Strength-Stress under compression to fracture orto produce a definite amount of deformation.2.78 Compression Test - A test for determining the maximum compres-sive load for producing a specified strain or fracture in a metal.2.79 Constitutional Diagr&n (Equilibrium Diagram)-A dia-gram showing the constituents of an alloy formed under given conditions( see2.146 ).2.80 Contraction Cavity- A cavity formed in an ingot a$&.~+&, >ofcontraction during solidification. Also referred to as shrinkage eavlty or-k ..pipe ( see Fig. 6, and 2.317 ).

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IS:1956(PartI)-1976

FIG. 6 CONTRACTION CAVITY, SHRINKAGE CAVITY OR PIPE2.81 Controlled Atmosphere ( Prepared Atmosphere ) - A preparedatmosphcrc which lwlps to control the cffcct of surfxtr tbxidation, dccarburi-zation, ctc, during heating, holding and cooling of steel.2.82 Cooling Curve - A time-temperature relationship shown graphicallyfor determining the arrest points ( see Fig. 1 ).2.83 Cooling Stresses- Stress developed in a material during cooling asa result of temperature gradients.2.84 Copper Bearing Steel - A carbon or low alloy steel containing aminimum of 0.2 pcrccnt copper for obtainin, w bcttcr atmospheric corrosionresistance.2.85 Copper Sulphate Test ( Preece Test ) - A test applied for assess-ing the quality of galvanized coating by dipping in copper sulphate solutionunder standard conditions.2.86 Core

a) The inner portion of rimming Steel.b) The softer inner portion of case-hardened or surface-hardened steel,

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ISr1956(PartI)-1976c) A preformed sand aggregate inserted in a mould to shape theinterior or that part of a casting which cannot be shaped by apattern.

2.87 Cored SWre - The structure arising from a composition gradientproduced in a solid solution and/or progressive freezing.2.88 Corrosion - Chemical and/or electrochemical attack on metals oralloys.2.89 Corrosion Embrittlement -An embrittlement caused in certainalloys by exposure to corrosive environment. It results from intergranulartype of corrosion attack.2.99 Corrosion Fatigue - Fatigue accelerated by corrosive conditions.2.91 Creep - The continuous flow of a metal or alloy when stressed belowits yield point or proportional limit. It is more marked at elevated tempera-tures and is, therefore, important in connection with metals and alloys forservice at high temperature.2.92 Creep Curve -A graphical representation between the deformationand time in a creep test.2.93 Creep Limit - The maximum stress, which a metal or alloy can with-stand without deforming faster than at a specified strain rate at a giventemperature.2.94 Creep Rate - The rate of strain during creep test under specifiedconditions of stress, temperature and time.2.95 Critical Cooling Rate - The slowest cooling rate from a giventemperature which can give a fully martensitic structure.2.96 Critical Grain Growth - The appreciable grain growth observedin critically strained steels when annealed under certain conditions.2.97 Critical Point ( Change Point, Critical Temperature andTransformation Point) - The temperature at which a. phase or amagnetic change takes place.2.98 Critical Range - The range of temperature within which the phaseor magnetic change occurs during heating or cooling.2.99 Critical Strain-The minimum strain required to produce criticalgrain growth.2.199 Crystal Grains ( Grains ) - The individual crystalline regions( crystallites ) which constitute in the aggregate the metal or alloy.2.101 Crystalline Fracture - See 2.48 and 2.69.

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I6:1956(PartI)-19762.162 cup and cone Fracture- The fracture of a ductile material intension, one half having a cup-like form whiie the other half has the formof a truncated cone which fits into the cup ( see Fig. 7 ).

FIG. 7 CUP AND CONE hACrURE2.193 Cmppimg Test - A ductility test for sheet and strip. This test in-volves forming a bulge or cup by stretch-forming the blank ( that is, a testpiece ) through a circular die with the aid of a special dome shaped punchand measuring the depth of the bulge or cup prior to fracture.2404 curie Point -to be magnetic. The temperature above which a metal or alloy ceases2.105 Cysu&le Hardening ( CyanMug ) - A process of surface harden-ing by introduction of carbon and nitrogen together, using a molten cyanidebath.2.106 CyanWng - See 2.195.2.107 Dam* capacity - The ability of a metal or ahoy to absorb theenergy of mechanical vibrations.2.108 Dead hft Steel - A very low carbon steel ehm by highductility, generally supplied in the fully annealed condition.

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lr19S6(Partf)-19762.109 Dccalescenes - Heat absorption without rise in temperature whena steel is heated through the critical range.2.110 Decarburization - Loss of carbon from the surface of steel usuallyduring heating, hot-working or heat treatment ( see Fig. 8 ).

FIG. DISOARBURIZED SURPACE LAYER OF STEEL SPECIMEN2.111 Deep Drawing - Forming cup shaped articles or shells by using apunch to force sheet metal into a die.2.112 Deep Drawing Steel-A high quality steel which permits deepdrawing.2.113 Deep Etch Test - Etching a suitably prepared specimen with acidto reveal defects.2.114 Delta Iron - The allotropi? form of iron which in pure iron existsbetween approximately 1400C and the melting point ( see Fig, 2 ). Deltairon has a crystalline structure similar to alpha iron, namely, that of the bodycentred cubic form.2.115 Dendrite -- A crystal with a fir-tree structure formed by the initialfreezing from a nuclcrls of primary? branches followed by the formationfrom these of secondary brrt:

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IS:19 Xi(PartI)-1976pre&rentially on the crystal axis of the first formed nucleus and later onthe parallel axis of secondary and higher order nuclei.2.117 bond iinoop Hardness Test -A test to determine hardnessby pressing a rhombus based diamond pyramid with an angle betweenlong opposite edges 172 and short opposite edges 130 under a standardload on to the surface of the material and measuring the longer diagonal ofthe indentation produced ( see IS : 68851913* ). The result of the test isexpressed as knoop hardness number ( KHN ).

KHN = Applied load in kgfSurface area of indentation2.118 Diamond Pyramid Hardness ( Vickers Pyramid Nasmerals ) -Hardness number determined by diamond pyramid hardness test.2.119 Diamond Pyramid Hardness Test ( Viekers Hardness Test ) -A test to determine hardness by pressing a square-based diamond pyramidwith an angle between opposite faces of 136 under a standard load into thesurf&x of the material, and measuring the diagonal of the indentation pro-duced. The diamond pyramid hardness number ( HV ).

Applied load in kilograms-forcef - Pyramidal area of indentation in mms

7.120 DiRerential Hea* - A method of controlled heating to obtain adesired non-uniform temperature distribution in a material.2.121 Were&al Qpenehing ( Selective Quenching ) - A method ofcontrolled quenching that results in different parts of a material achievingdifferent hardness.2.122 Di&si&n - A movement of atoms within a solution which may bea liquid, solid or gas. The net movement is usually in the direction fromregions of high concentration towards regions of low concentration.2.123 Dilatometly - The test is used to evaluate minute length changesVera temperature/time of steels and other materials to investigate phasetransformation, recrystallization, precipitation, thermal expansion co_e@icient, etc.2.124 IXvonxd Pear&e - Pearlite heat-treated to render its cement&constituent spheroid&d ( also called spheroidized carbide as distinct fromlame&r car bide ) .2.125 Drift Test ( pip Expansion Test ) - A test for plate, carried outby boring a hole ofa given diameter near the edge of the plate and enlargingit by a conical tool having a specified taper until either a specified increase in

*Method for knoop hardness testing of metals.19

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lS:1956(PartI)-1976diameter takes place or cracking occurs. The test is also applicable to tubes,in which the diameter is increased at one end by forcing into the bore amandrel of specified taper ( seeulso 2.157 ).2.126 Dtop Test - A test carriedout on a material to determme its resist-ance to fracture or breakage under specifk conditions. The usual form ofthis tert is to drop the finished article ( such as, tyre wheel, a sealed hollowreceptacle containing liquid, etc ) from a predetermined height.2.127 DUctility- Ability to undergo plastic deformation usually as a resultof tension.2.123 Dmmp Teat - A test to detect surface defects in materials intendedfor cold-or hot-forging. The test is carried out by upsetting a test piece ofsuitable length either cold, or after heating to the forging temperature,as the case may be, till a specified reduction is obtained.2.129 Ihs@e x StrucOsre -A microstructure made of two phases.2.130 Dynamic Stra@h - Strength of a material when subjected tosuddenly applied or changing loads.2.131 Elastic D&rmation -A reversible change in dimensions underapplied stress.2.132 FJasfieity - The property of a metal or alloy which permits returnto its or&&l dimensions on removal of applied stress not exceeding itselastic limits.2.133 Elastk Limit- The maximum stress ( generally in tension ) amaterial can withstand without suffering permanent deformation.2.134 Ezcctro-G4lvnniang - Zinc coating by electrodeposition.2.135 Etcctrolydc ( Galvanic ) Cos7osion - Preferential corrosion of amed having electrical contact with another metal or conductor.2.136 MpoEsbiug ( Electrolytic Polishing ) - A process of pohsh-ing d and alloys by an electrolytic treatment.2.137 E&ctro-Thning ( Tindug) - Tii coating by electrodeposition.2.133 Elongation - The increase in length of a tensile test piece understress. Tbe elongation at fracture is conventionally expressed as a percen-tage of the original gauge length of the standard test piece.2.139 End Quench Hardenability Teat (Jominrp Test )- A test inrVhichthe test piece is heated to a suitable temperature above the tram+formation range and then quenched at one end. The gmdaric?nof hardness&,:tg the length is then determined. The most copya~n fcKmofthistutis the Jominy t

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IS:1956(PartI)-19762.149 Endurance Limit ( Fatigue Limit ) - The maximum stress belowwhich a material can presumably endure an infinite number of stress CYC~.If the stress is not completely reversed, the value of the mean stress, theminimum stress or the stress ratio should be stated. When the mean valueof the stress is zero, the endurance limit is equal to halfof the maximum rangeof stress.2.141 Endurance Range ( Fatigue Range) -The maximum rangeof stress, which the material will withstand for a speciEed large number ofstress cycles. When the mean value is zero the fatigue range is twice thefatigue limit.2.142 Endurance Ratio (Fatigue Ratio) -The ratio of fatigue limitto the ultimate tensile strength.2.143 Endurance Test ( Fatigue Test ) - A test to determine the fatiguerange ( endurance range ).2.144 Energizer - Subfiances ( for example, barium carbonate andsodium carbonate ) used in carburizing mixture for accelerating the car-burizing process.2.145 EqM Crystds - Crystals which have axes approximatelyequal in length.2.146 E+biium Diagram ( Phase Diagraaa ) -A diagram showingthe limits of composition and temperature within which the variousphases of an alloy may be formed, or exist under equilibrium conditions( see Fig. 9 )..2.147 Erichwn Tut-A test for sheet in which the depth of impressionat fracture, obtained by forcing a cone-shaped plunger with a spherical endinto the test piece, is measured in millimetres and used as an index of draw-ability.

2.148 Etchbg -Treatment of prepared metal surfaces with suitablereagents for revealing the structure by preferential attack on crystal grainsor the phases.2.149 Eutexdc - A mixture of two or more constituents, which has thelowest f&zing and melting points.2.150 E&a&& Point-The point in the phase diagram indicating thecomposition and solidification temperature of an eutectic.2.151 Eutectic Structurepoint.

-The structure corresponding to the eutecticIn general this is lamellar and IS produced by simultaneous solidi-tication of tire constituents forming the eutectic.

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hATOUIC PERCENTAGE CARBON I9

Ial-FcI -FERRITE

;g 0

Fe 0.1 0~2 O-3 0-L 0.5 MT 0.7 1.0 14 l-2 l-3 1.4 l-5 l-6 1.7 14 1.9 2.0 2.1 2.2_. _-WEIGH1 PERCENTAQE,CARBON

Fxo. 9 EQIJILIBRIUM IAGRAM

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IS:1956(PartI)-1976 2.152 Eutectold - The mixture of two or more constituents formed ata constant temperature from the breakdown of a single solid solution duringcooling and which transforms into a solid solution during heating.2.153 Eutectoid Point - It is a specific point in the phase diagram mdicat-ing the temperature and phases corresponding to an eutectoid.2.154 Elrtectoid Steel - Steel of entirely eutectoid structure, that is whollypearlitic.2.155 Eatectoid Structure - The structure, usually lamellar, correspond-ing to an eutectoid.2.156 Exfoliation ( Flaking ) -- Spalling away in the form of thin flakesfrom the surface of a material. This may result due to corrosion in the caseof metals or thermal shocks in the case of hard metals and refractories.2.157 Expanding Test - A test mostly used for tubes in which one end ofthe sample is expanded, by means of tapered grips, to a specitied diameter.2.l56 Falling Weight Test - A test applied by dropping a specifiedweight from a definite height on to the material to be tested. Normallyapplied to tyres, axles, rails, etc, when a maximum deflection without fiat-ture is usually specified.2.159 Fatigue - The tendency to fracture by means of a progressive crackunder repeated alternating and/or cyclic stresses considerably below thetensile strength.2.169 Fatigue Fracture - The characteristic fracture associated withfatigue failure.2.161 Fatigue &it - See 2.140.2.162 Fatigue Range - See2.141.2.163 Fatigue Ratio - See2.142.2.164 Fatigue Test - See2.143.2.165 Flakes - See2.198.2.166 Ferrite-The microconstituent corresponding to the crystallineform known as alpha iron ( which has a body-centred cubic; lattice ).Many alloying elements ( for example, nickel, manganese and silicon ) aresoluble in alpha iron, hence the term ferrite refers also to such solid solutions.2.167 Ferritic Steel -A steel which contains essentially ferrite ( BCCstructure ) as the microconstituent.2.166 Fibre - An elongatedarrangementof the plasticconstituentsof thestructuredue to working and is usually revealed by etching.

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Isr1956(PartI)-19762.169 Fibrous Fracture - A dull grey fracture in which considerabledistortion has occurred, indicative of toughness.2.176 El8ldng - se&2.156.2.171 Flame HarduGng - Rapid heating of the surface, by means of anoxy-gas flame to a temperature above the transformation range, followed byimmediate quenching ( usually by means of a water jet ).2.172 Fian&sg Test - A test for tube in which the end of the tube isturned back to form a flange at right angles to the axis of the tube.2.173 Flatteniug Test - A test for tube in which a short length of thesample tube is flattened diametrically by a specified amount.2.174 Plow Line-Pattern revealed by suitably etching the preparedsurface of a wrought material revealing the directional flow during working.2.175 Fracture Toughness Twit - The test is used to evaluate the re-sistance of the material to crack propagation under given conditions of racksize, geometry of the specimen, environment and the nature of the appliedload.2.176 Free Gementite - Cementite not associated with pearlite.2.177 Free Cutting Steel - Steel in which special addition of such ele-ments as sulphur, lead, etc, are made to enhance machinability.2.178 Free Ferrite - Ferrite not associated with cementite.2.179 Mvanixin g - Process of depositing zinc on a metallic surface( see 2.134 and 2.215 ).2.186 Gamma bon (or Iron)- The face-centred cubic form of ironstable between approximately 910 to 1400C.2.181 Gangne - Part of an ore, which has to be either removed duringbenefication of the ore, or slagged during smelting.2.182 Gas Carburizing - Carburizing in a gaseous medium of suitablecomposition.2.183 Gas Cyaniding - A process of surface hardening of steel by heatingin a suitable gaseous atmosphere so that carbon and nitrogen are simul-taneously absorbed by the steel, followed by desired rate of cooling.2.184 Gas Welding - A group of processes, wherein welding is e&ted byheating with a gas flame or flames, with or without the application of pressureand with or without the addition of filler metal.

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IS:1956(PartI)-19762.185 Gauge Length

a) The specified length in the tensile test piece over which elongation/ is measured.b) The length under test in torsion and compression test pieces.

2.186 Ghost ( Ghost Lines ) - A segregated streak, usually containing aconcentration of sulphide, phosphide, oxide, etc, lower in carbon thanthe surrounding material ( SC also 2.311 .2.187 Grain Boundary- The boundary outlining a crystal.2.188 Grain Growth - Increase in the size of grains associated with Heat-ing to high temperatures. Gram growth also occurs during normal sub-critical annealing after critical amount of cold reduction.2.169 Grain Retitr - A substance added to the molten metal or alloy toproduce finer grains.2.196 Grrin Refining - Heating appropriately through the transforma-tion range followed by cooling suitably from above that range, for obtainingdesired refinement of grains, which may also be obtained by controllingthe finishing temperature of hot-worked material or by suitable cold workfollowed by annealing.2.191 Grain Size-The size of crystal constituting a material and isexpressed by the number of grains or crystals per unit area.2.192 Grain Size Control - A control exercised during s-eel making andfinishing for obtaining a steel with the desired requirements for grain size.2.193 Grain Size Nnmbtr - A number ( .N) to classify the gram size onthe basis of the total number of grains ( A ) in an area of 2.54 x 2.54 cm*at a magnification of 100 diameter, the relation being

The gram size number and the total number of grains are shown inFig. 10.2.194 Graphitic Carbon - Carbon present in the form of graphite.2.195 Graphitic Steel - Steel which contains small amount of carbon inthe form of graphite.2.i96 Graphitiziq - Heating and cooling in a controlled manner so as totransform the combined carbon to graphitic form ( for example, free carbon )of desired size and amount.2.197 Grirrding Cracks- Cracks appearing in a network pattern andarising from excessive heat generated during grinding ( see Fig. 11 j

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19t19 i6(PartI)-19762.198 Hair Line Cracks ( Flakes ) - Internal ruptures in steel caused bystresses which probably arise from the combination of several fwtors, suchas volume changes due to transformation, brittleness due to the presence ofhydrogen and the arrangement of the microstructure, resulting from h\t-working. The size of such ruptures may vary considerably but they areusually comparatively short in length when viewed on a surface cut at rightangles to the plane of defect, and generally are so fin- that they cannot bediscerned except after etching or by magnetic crack direction.

2.I98.1 SrwwJlakes When hairline cracks are exposed by fracturing,they appear as bright crystalline areas of almost circular form, sometimesknown as snowflakes.2.199 Hardenability - The property that determines the ability of a givensteel to harden right through and is assessed by measuring hardness distri-bution from surface to interior after quenching under specified condition( see 2.139 ) .2.200 HardezuSIity Test -A test for assessing hardenability ( see2.139 ).There are other methods also for determining the hardenability which areused for specific purposes.2.201 Hardening- Any process which increases the hardness, for example,quenching from or above the transformation range, or cold-working.2.202 Hardness - Resistance to indentation, abrasion, deformation,scratch, etc.2.203 Hardness Test - A test to determine the hardness and is generallymeasured by the resistance of the material to deformation under standardconditions. There are various forms of this test using different instrumentsfor measuring indentation ( for example, Vickers, Rockwell, Shore, Brine&etc ).2.204 Heating Curve - A graph constructed by plotting the temperatureagainst time when a material is being heated m a regular manner. Any arrest in temperature indicates constitutional change ( see 2.82 ).2.203 Heat Resisting Cast Iron - An alloy cast iron suitable for hightemperature acrvice ( above 400C ).2.2lKi Heat Resisting Steel - An alloy steel generally containing highpercentages of chromium and/or nickel and possessing enhanced resistanceto scaling coupled with good mechanical strength at high temperatures.2.207 Heat Tinting- A process for developing colour on a speciallyprepared surface by heat, the object being (a) to impart a protective film,and (b) to reveal crystalline structure by affecting different constituents in adifferent way.

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As in the Original Standard, this Page is Intentionally Left Blank

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Is:1956(ParrI)a76

Fm. 11 GRINDING CRACKS2.299 Heat Treatment - Combination of heating and cooling operationsin a prescribed manner ( with respect to time, temperature and rate of heat-ing and cooling ) to induce desired properties in metals and alloys in the solidstate. The conventional heating for hot-working does not come within thescope of heat treatment.~;~oIeterog - Variation in composition in a given piece of metal.2.210 High carbon &eel - Carbon steel containing generally more than0.60 percent carbon.2.211 High Speed Steel- A special variety of tool steel which, by virtueof its composition, retains iti cutting hardness at a low red heat (seeIS : 7291-1974 ).2.212 Homogen&y - Uui&ormity of compasition in the same piece ofmetal.2.213 Hookes Law -The law de6ning stress-strain relationship undercertain condition, namely, within elastic limit the strain produced is pro-porional to-the applied stress.2.214 Hot-Forming- Operations, such as bending and pressing, afterheating the material to appropriate temperature.

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Is:1956(PartI)-19762.215 Hot Gdtig ( Hot-Dip Cd-) - Coating with zincby immersion in a bath of molten zinc.2.216 Hotshortness - Tendency to crack during hot-working.2.217 Hot Tinning - Coating with tin by dipping into a bath of moltenmetal.2.218 Hot-Working - The operation of plastic deformation of metals andalloys at appropriate temperatures in a manner that no strain hardeningoccurs during such operation.2.219 Hydraulic Test (Hydrostatic Teat, Pressrue Test ) -A testfor tubes or hollow products in which the test samples are subjected to aspecified internal liquid pressure.2.226 Hydrogen Embrittlement - Loss in ductility due to the absorp-tion of hydrogen.2.221 Hydrostatic Test - See 2.219..2.222 Hyper-Eutectoid Steel - Steel containing more than eutectoidpercentage of carbon.2.229 HyPo-Euteetoid Steel - Steel containing less than eutectoid per-centage of carbon.2.224 Impact Test ( Notched Bar Impact Test ) - A test to determinethe behaviour of metal under suddenly applied stresses.2.225 Inclusions ( Non-an- Incluaio~~ ) - Non-metallic materialslike oxides, sulphides, silicates, refractories, etc, embedded in the metal.2.226 Indentation Hudsle8r - Hardness value derived by an indentationmethod.2.227 lsldllctionHardtninS- Process of hardening by induction heatingto the appropriate temperature and quench&r iu a suitable medium.

NOTE This process is generally applied to mrfkce hmdmiog but my also beapplied to full hardening.2.228 Uction Hardng-Process of heating by electrical inductionmethod, that is, by induced current.2.229 Iagot- Castings of suitable shape and size intended for subQequmthot-working.2230 Ingot Iron-Very low carbon steel genetally made iu the opeuhearth containing very small amounts of other elements.2.231 Ingot stmctmre - Crystalline amaugment (for cxamplq chill,cohumar and cqui-axed crystals) in an ingot.

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ISr1956(PartI)-19762.232 Imherut Grab S&m- Au&e&e grain size devcioped understandard conditions ( SH 2.2?1).2.233 I&lb&or -Sud ( generally organic in nature) added inpickling bath to minimize metal loss.2=4W Corro&n (IW=g==* corrw;on)-Corroeion which ocm along grain boundaries.2.2% In- Fnc&ure -A fracture occurring along grainbolu&ri* fW exaklpk~ a creep fkacture.2.236 In- carrodon-~sca~.2a237 Imtemd stres8 -S&es8 existing within a metal as a result oftmnsfmtion, tcnlpeWUe g@ients or mechanical working.2z8 Lteln#ed Q?&&in& - see 2.418.2.239 v Fnltturt -Fracture taking. place across thegrainsorcrystalsinametal.2240 hvame &gre@a--S882.36@.2.241 k&ermal Tmadwmatiom -A transformation of austenitetaking place at a corutant tanpapiture.2.242 kod Impnet Temt (No&&d Bar hpact Test)-A type ofimpact test wherein a test piece, witb a standard V-shaped notch and f&dat one end, is struck by the blow of pendulum and the energy thus alxorbedin facturing the test piece ( recorded by the testing machine ) is measured( see IS : 159&-196W ).2.243 J &s Bend Test - An alternating bend test through an angle of180 carried out with a machine having a constant radius of bend.2.244 J on&y Test - Su 2.139.2=246KeyIBoIeNoedr -A type ofnotch (which takes the shape of alctyadc) used in Charpy impact test.2.246 Knock Darrr Test-See 2.426.2.247 Luuinadnns -A defect in rolled materials, characterized by atendency to split into layers along the directions of rolling usually due to thepresence ofnon-met&c inckiions or other diiontinuity in the steel.2.246 Lap ( Overlap ) - A surface defect, similar to a seam in appearanceand is caused by folding over of hot steel in th form of fin, sharp corners,etc, on the rolled surface, and subsequently, r&xi or forged but not we&dto the surface.

kkttwd or hod impact test for steel.31

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fst1956(Parti)-19%2.249 Lead-Bearing Steel - A steel containing lead ( about 0.20 percent )for obtaining better machinability.2.259 Lclld Patenting - A patenting PA ess where quenching is carriedout in a lead bath ( see also 2.392 ).2.251 Ledeburite - The eutectic of iron and iron carbide system sohdify-ing at about 1130C. It is made up bf austenite and cementite, andcontains about 4.3 percent carbon.2.252 Limit of Proportionality (PropoHh4 Limit) -The stress( that is, load per unit area of the test piece ) at which the strain ( that is,elongation per unit gauge length ) just ceases to be proportional to theapplied stress.2.253 Liquidus - The lines (in a two-component system ) or surfaces( in a three-component system ) in equilibrium diagrams representingtemperatures at which solidification commences during cooling, or meltingcompleted during heating.2.254 Load-Extension Curve ( Stress-S& Curve ) - A graphicalrepresentation showing the relationship between appikd load and elongationof the test piece in a tensile test (se8 2.100 ).2.255 Local &tension - The elongation produced in a tensile test piecewhere necking occurs.2.255 Luder Lines - See2.401.2.257 l&cm+t& - Etching prepared surfaces with acid or other suitablereagent to reveal macro-structure flow lines and defizets.2.258 Macro-atractuW - The crystalline structure and the distributionof impurks on the macro-etched surface visible to the naked eye or underlow magnification ( not exceeding 10 diameters ).2.259 Mapetic Ch8nge Point or Magnetic Transforma tion Point( Carie Point ) - The temperature at which iron loses its ferromagnetismon heating and recovers the same during cooling ( temperature COReSpOndingto this point for pure iron being about 770C ).2.269 MaSnetic Crack Detection-A method of detecting surface andsub-surface flaws. It is carried out by magnetising the surface to be examinedand then covering it with very fine magnetic powder either in emulsion formor in solid form then draining off the excess oil. At d&continuities, leftby cracks, there will be change in magnetic flux, as such the magnetic powder aligns itself accordingly on tte surface, giving well formed patterns outlining the cracks.2.261 Malleability - Capacity for undergoing deformation in aU direc-tions, usually cold deformation by hammering or squeezing.

x2

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fs:isss(PirrrtI)-i9%2.262 Ma&a?& Gast Iron ( Malleable Iron ) - Cast iron that is castwhite and made malleable by annealing in an oxidizing or neutral medium( see also 2.32 and 2.438 ).2.263 MaUeabilWag - The process of annealing white cast iron so as totram&m combined carbon partly or wholly ( depending on the type of theproduct desired ) into graph& carbon. In some instances, the carbon isremoved partly or completely from the white iron.2.264 wese Steel- A steel which contains only manganese asalloying element. Generally it refers to the austenitic variety containing12 percent manganese.2.265 Martempering -An isothermal treatment in which the object isquenched from a suitable austenitismg temperature to a temperature slightlyabove the MS point and held at that temperature for a suitable length of timefor equalizing temperature and then cooled in air. The martensite thusformed is then tempered as desired ( see Fig. 12 ) .2.266 Martensite - The hard mi&constituent formed when a steel iscooled appropriately from above the transformation temperature, that is,cooled with a speed faster than its critical cooling rate. It is generally aninterstitial super saturated solid solution of carbon in iron having a bodycentred tetragonal latice and its microstructure is characterized by an acicularor needle-like pattern.2.267 Martensite Transformation ( Mf Point, MS Point ) - Thetransformation of austenite to martensite. It takes place very quickly overa range of temperature and is largely believed to be diffusionless. Thetemperature at which the transformation commences is termed as MS pointand the temperature at which the transformation is completed is termed asMf point.2.269 Martensite Transfarmation Range - The martensite transfor-mation takes place over a range of temperatures depending on the rate ofcooling. The temperature at which the transformation begins is termed asMS point and the temperature at which the transformation finishes is termedas Mf point ( see 2.267 ).2.269 Mass Effect - The effect of mass, that is, thickness, size and shape,in causing a variation in properties at different depths in a heat-treatedmaterial arising from difference in cooling rate of different portions.2.270 Maximum Stress -- The maximum load reached in a tensile testdivided by the original cross-sectional area of the gauge length portion of the Itest piece. Also called as ultimate tensile stress or tensile strength .2.271 McQuaid-Ehn Grain Size - A measure of the size of crystal grainsfirst suggestedlby Mc@aid, and refers to grains developed in steel carburixed

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IS; 1956(Parc I)-1976MARTEMPERING

UPPER TRANSFORMATION TEMPERATURE-----a-a------ ----_

PRODUCT = TEMPERED MARTENSITETIME - LOG SCALE

Fm. 12 SCHEMATICRANSFOWATIONIAQRAM OR MARTEMPERINGat 925C for 8 hours and then cooled in furnace resulting in a hyper-eutectoidcase with cementite outlining the austenite grains.2.27 I l&&a&al Propertits - Properties which are determined byme&n14 methods involving destruction or Formation or both, such asttkk test, bend test, impact test and hardness. These properties are indi-cative of elastic and non-elastic behaviour of metals under applied stress.~A~_trength- Strength evaluated on the basis of

3374 Me&m Cubon Steel - Carbon steel containing generally mini-~dO3Opercuatcarbonand maximum of060 percent carbon.34

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1 18:1956(Part1)-19762.275 Mealurger Not& - U-shaped notch used in some Izod impact test.2.276 Metallography - The study of the constitution and structure ofmetals and alloys with the aid of a microscope.2.277 Microstrncture - The structure of metals or alloys revealed ( afterpolishing and etching ) under the microscope.2.278 MiddIe Half of Gauge Length - The central half of the guagelength marked on a test piece.2.279 Mild Steel - Carbon steel containing generally less than 0.30 percentcarbon.2.289 ModnIus of Elasticity ( Youngs Modulus ) - Ratio of directstress to strain within the elastic limit, in tension or compression.2.281 Modulus of Rigidity-Ratio of shear stress to strain within theelastic limit, in shear.2.282 Necking - It is the localized reduction in cross section occurring ina ductile material under tension before fracture.2.283 Network Structure - See 2.63.2.284 Neumann Bands- Thin twin bands running parallel to certaincrystallographic planes observed ( after polishing and etching ) in ferritecrystals deformed by impact without any prior straining. Slow strainingitself or slow straining followed by impact does not reveal such bands.2.285 Nicked Fracture Test - A, test for welds in which an examinationis carried out of a fracture obtained by nicking or sawing a small part of thecross section of a specimen and then breaking the same by bending.2.286 Nitriding - A process of surface hardening by introducing, nitrogeninto the surface in a suitable steel by heating and holding it at appropriatetemperature in contact with cracked ammonia or other suitable nitrogenousmedium.2.287 Non-metallic Inclusion - See2.225.2.289 No-g- A process of heat treatment for improving mocha-nical properties brought about by grain refinement and uniformity in struc-ture. The process involves heating to and holding for a specified time at asuitable temperature above the transformation range, followed by coolingfreely in air.2.289 Notch Brittleness - Tendency of a metal to fail by brittle fractureat a notch or stress raiser by a suddenly applied load.2.296 Notched Bar Impact Teat - See 2.224 and 2.247.

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IS:1956(PartI)-19762.291 Notch Sensidvity - Reduction in nominal strength, impact or static,caused by stress concentration due to a notch or any stress raiser, and 1susually expressed as a ratio of the notched to the unnotched strength.2.292 Notch Toughness - A high resistance to fracture under suddenlyapplied loads at a notch or other stress raiser.2.293 Open Annealing ( Black Annealing ) - See2.31.2.294 Open Coil Annealing ( Unitized Anncaliqg ) -Annealing of asheet coil in the form of a loosely wound coil with or without a metal spacerbetween successive laps of the coil, thus providing gap for the atmosphere tocirculate around each lap of the coil. This form of annealing is generallyused for decarburization annealing and/or denitriding, that is, annealingsimultaneously with decarburization and de riding to produce extra lowcarbon and low nitrogen steels. Generally it is carried out in Bell typefurnaces, but when carried out in Bogie Hearth Furnaces the process is usuallytermed as ( unitized annealing .2.295 Open Hearth Furnace - A furnace having a dish shaped hearthin which the bath is heated by convection from the flame over the surfaceof the metal and by radiation from the roof. Commonly used for steelmaking.2.296 Overaghg - Softening which follows ageing by prolonged heating,at the ageing temperature.2.297 Overlap - SM 2.248.2.298 Overheating- Heating to such a high temperature that anundesirably coarse grained structure is produced. Severe overheating mayresult in the properties being permanently impaired ( see Fig. 13 ).2.299 Pack Annealing - Closeannealing of packs of sheets.2.300 Pack Rolling - Rolling two or more sheets at a time.2.301 Passivity - The state of remaining unattacked chenucally af)era slight initial attack due to the formation of a protective film.2.302 Patenting ( Air Patenting ) - Heating to an appropriate tempera-ture above the transformation range and then cooling at a controlled ratein the desired medium (for example, air, lead or a salt bath ) to producestructure desirable for subsequent cold-working. Usually this is applied towire drawing.2.303 Pearlite - The microconstituent of eutectoid composition revealing,under the microscope, alternate layers of ferrite and cementite. In theiron-carbon system this constituent contains slightly under 0.9 oercentcarbon.2.304 Preece Test - Sss 2.85.

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I6:1956(PartI)-1976

FIG. 13 COARSEGRAIN STRUCTUREDUE TO OVERHEATING2.305 Peritactic Change ( Perit&& Rwction) -A reversibIe changeinvolving the formation of a new solid phase at a constant temperatureas a result of the reaction between a prior solid and a liquid phase of analloy. During heating the change proceeds in opposite direction.2.306 Pemdloy - Nickel alloys containing 20 to 60 percent iron, usedfor their high magnetic permeability and electrical resistivity.2397 PCsent Magnet steel - A heat-treated special steel of suitablecomposition possessinghigh coercive force and remanance and, therefore,suitable for use as permanent magnets.2396P ernaanmt 6et (Plastic Deformation ) - Deformation existingafter the removal of the applied load ( that is, the material does not revertto its original dimension after the removal of the load ) ( see2.318 ).2a Phase -A completely homogeneous, physically distinct andmechanically separable portion of a metallic system.2210 &se XHagrsW - srs 2.146.

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I8:1956(PartI)-1976 *2.31 I Phosphlde Streak - An elongated area of segregated phosphideswhich is revealed on etching.2.312 Photomicrograph - A photographic reproduction of the micro-structure.2.313 Pig - Molten metal cast into suitable shapes intended for remelting.2.314 Pig Iron- The primary product of smelting iron ore containingusually between 3 to 4.5 percent carbon along with silicon, manganese,phosphorus and sulphur in varying amounts depending upon the qualityof raw materials used. Pig iron is used in the foundary or for conversion intosteel.2.315 Pin-Head Blister - See2.37.2.316 Pin Hole Porosity - Minute holes scattered throughout thesurface of a casting resulting from micro-shrinkage or gas evolution duringsolidification.2.317 Pipe ( Contraction Cavity, 8hrinkage Cavity ) - An axial cavitycaused by contraction during solidification of an ingot. Also the defectsarising from the axial cavity on the semifinished or finished products. Itmay also refer to tubular sections.2.318 Plastic Deformation - See .308.2.319 Plasticity - Ability of a metal or an alloy to undergo plastic de-formation without rupture.2.320 Poissons Ratio - The ratio of transverse strain to the longitudinalstrain under tension or compression within the elastic range.2,321 ?olymorphism - See 2.8.2,322 Pvt Quenching - Direct quenching from the carburizing operatibn.2.323 Precipitation Hardening - Hardening caused by the precipitationof a constituent from a super saturated solid solution.2.324 Preheating-Heating at a modcrate temperature carried out as apreliminary to further heating at a higher temperat.ure.2m Prepared Atmospherk - See2.81.2.326 Pressure Test -See 2.7 and 2.219.2.327 Primary Carbide - Carbide in excess of the eutectic composition.This term is also used for carbide in excess of eutectoid composition.2.328 Primary Crystals - The first dendritic crystals which form in an&y during cooling below the liquidous temperature.

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&:1956(PartI)-19762.329 P&&pat Stresses - Normal stresses along rectilinear co-ordinatesso chosen that shearing stresses are zero.2.330 Process Annealing- Sub-critical annealing applied in sheet andwire industry for the purpose of softening for further cold-working (~66also 2.13 ).2.331 Proof Rend Test -A test in which a tube, supported suitably, isloaded to give a specified bending moment.2.332 Proof Stress - A stress that will cause a specified permanent ,defor-mation in a material, usually 0.1 percent of the gauge length.2.333 Proportional Limit - See2.252.2.334 Quenching - Rapid cooling.2.335 Quenching Cracks - Cracks resulting from thermal stresses inducedon rapid cooling or quenching.2.336 Radial Test - See2.425.2.337 Rams Horn Test - A test for determining the suitability of wroughtiron or steel for forging, and is carried out by punching a hole near the endof test bar heated to forging temperature, drifting the hole, splitting longi-tudinally to the adjacent end of the bar and finally doubling the partedportions backwards.2.336 Range of Proportionality-The part of stress strain curve overwhich the strain is proportional to the stress.2.339 Recalescence - Evolution of heat during cooling through the trans-formation range of the steel or iron, associated with gamma to alpha trans-formation on cooling and is revealed by brightening ( reglowing ) of metalsurface.2.346 Recalescence Point -The temperature at which recalescenceoccurs ( see also 2.97 .2.341 ,RecrystaRization - The change from one crystal structure toanother occurring on heating or cooling through a critical temperature.The formation of new, strain free grain structure from that of cold workedmetal on heating, is also called recrystallization.2.342 Recrystallization Temperatbre - The temperature at whichrecrystallization commences.2.343 Red Hardness - The relatively high hardness retained by certainspecial steels ( for example, high speed tool steels ) even when heated up toa bw red he+.

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I&l #Ui(PartI)-19162.344 Redaction of Area - Percentage reduction in area of a tensile testpiece after fracture. The difference between original area of the cross sec-tion and the smallest area at the point of rupture of the tensile test piece,when expressed as percentage of the original area, gives this value.2.345 Refiping - The removal, by slag or other reactions, of undesirableelements and of metallic oxides and gases from molten steel..2.346 m - A heat-resistant material usually non-metallic, used fbrfm King to withstand high temperatures.

w - Arrangement ( chambers filled with a checkwork of_y&cs j& receiving and then utilizing heat from hot spent gasa *2.34% Reshhd krrru; - &rc~w~&sti+ within a metal in absene~ of OFin addition to, the street canscd by external load. These stresses cc&d bepresent due to mechanical defe UkernsaI expansion/contr@iionelectro- or magneto-striction or due to &IL~~cc-RRopertyoFarm~~,actuntE~~oiep~~~~and after the removal of the strew that baz prcuhsced elastic strain. ThisismeasnredasenergyperunitvoItrmercIea&uponnnlo&ng.2.3S Reverse T&Test-A testfor. wireserrried out bytwistingthe test piece a specified number of imesn one direction and then in theopposite direction.2.351 Rivet Test-A test for rivets. It consists of two parts, namely:(a) for shank, and (b) for the head. In (a) the shank is bent cold andhammered till the two parts of the shank are in contact with each other,without showing any sign of fracture on the outside of the bend. In (b)the head is flattened hot until its diameter is 24 times the diameter of theshank, without showing any crack.2.352 RockweR Hardness Test-A hardness test for measuring the in-dentation hardness using an indentor in the form of a diamond cone, or ahardened steel ball. The hardness value being read directly on the dialof measuring instrument ( see IS : 1586-1968* ).2.353 Ruling Section - Limiting cross section of a bar which would obtainuniform mechanical properties on heat treatment.meter of a round bar. It is expressed as a dia-The rectangular or other sections are expressed asequivalent round sections by applying conversion factors.2.354 Scab - Irregular shaped patches of metal on ingot surface arisingfrom cavities in mould walls or caused by loosely adhering layers of metal.Methodsfor Rockwell ardness est ( B and C reala ) for eel (jirs#noirirn.

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Is:.l95s(PartI)-19762.355 && - Oxide fossned on the surface of steel or iron after heatingunder ax&k&g conditions.EzJW Hardnesu Tea (Shore ScIe roscope Hardness-A test m which hardness is measured by noting height of reboundof a &e.ly falling diamond pointed tup or hammer ( placed inside a graduat-ed glass tube ), corn a 6xed height on the smooth surface of the specimen tobetested.2.357 &&rve ( TTT Diqram ) - An isothermal tran&onnation curveshowing the time taken by austenite to transform isothermally at varioustemperatures between A3 and commencement oftransformation ( Ms ). Itis sometimes called 23 cprv-e becau31~ he curue hi a shape like-letter- S 6-xsomesteeksuchaspkmcarbonsteek ltkahca&d~mtme,asmaaycurveshavtasbapchkektterC I;r:ixealIedTTTdiag~&becanscitrepresents tixWtempera_ rektkmhip fH#Eg.. M).2.35S&asn-LongshaUowgrooveorsGa&mf&rm&dttringroWngbythe elongation of ox%zed surface 01 subsa&bce UYW he&es. Seams mayalso be caused by rippkd surf&es or by recurrent teeming laps-2.% l Sa~~daq~---Apbenomenasr -tbattakespkceincertaintypesofhardenedsteek(farexampk,highspeedsteel),;md resultsibgreater hardness on temper& atsomehighertemperature~thanwouidbeobtained by tempering the same steel at lower temperature-2=366 Sqgqation- A non-uniform distribution of some constituentsand/or impurities, in a cast product characterized by the mode of sohdi-fication of alloys. Segregation usually persists through subsequent hot andcold-working. Generally, the concentration of low melting point consti-tuents tend to be higher in the centre than the surface. Sometimes, thereverse of this phenomenon takes place and is known as ixmme segregation.2.361 SeWXardening Steel - SCG.6.2.362 Shear Crack -A diagonal tmnsgmnular crack caused by shearStlTSS.2.363 Sheas+nS Test - A form of shear test to determine the stress requiredt cut or shear the material across its section.2.364 Shear Test -A test to aetermine the resistance to sliding of oneportion over the other when a material is twisted.2.363 Shrinkqe Cavity - See 2.317.2.366 Sigma Phase - Hard and brittle non-magnetic inter-metallic phasewith a tetragonal crystal structure found in many binary and ternary alloysof transition elements, for example, in chromium steels.

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600

1

t AUSTENITE (STABLE 1

4 I I I It1 10 10 l0 10 lo5 lo6

TIME IN SECONDS14A TTT Curve for Plain Carbon Steel

800700

OU 600+w 500as 4008g 300p 200

1000

F - FERRITEf -CARDIDE

i TRANSFORMATION END550 TRANSFORMATIONTRANSFORMATION STARTS1 10 lo* IO3 lo4 lo

TIME IN SECONDS148 TTT Curve for 3.4 Percent Ni Steel

FIG. 14 TTT CURVE

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IS:1956(PartI)-19762.367 Silky Frttturt - Fracture showing very fine grains and smooth greyappearance, characteristic of tough and strong metals.2.368 SIip- Sliding of a part of a crystal over the other along certainplanes, known as slip planes. It is by such sliding movements that deforma-tion occurs as a result of stress.2.369 Slip Bands - Parallel lines acrossindividual crystal observed undermicroscope, in a cold-worked metal.2.370 Slg Test -See 2.429.2.371 Snarl Test -A workshop test applied to wire which is looped,pulled taut, unlooped, pulled taut again, the operation being repeateduntil fracture occurs.2.372 S/N Curve ( Stress Nssmber Curve ) -The curve derived fromthe number of cycles of stress to produce failure when plotted against therange of stress from a series of fatigue tests.2.373 Snow Flakes - See 2.198.1.2.374 SorLiy - Holding the material in a furnace after the outside hasreached the desired temperature until uniformity of that temperature hasbeen reached throughout its mass and any desired metallurgical changeshave been completed.2375 So&enin6- Reducing the hardness by heat treatment? usuallytempering, but at times, annealing, primarily to facilitate machmmg.2376 &&Micah Range The range of temperature over which f&z-ing takes place.2377 Solid Sol&i&y - Extent to which one constituent is soluble inanother, in the solid state, to form a solid solution.2.378 Mid SoUfon - Two or more constituents forming in the solid state,a single homogeneous phase.2379 Solidus -The lines of surfaces ( depending on whether two or moreconstituents are involved ) in thermal equilibrium diagrams indicating thetemperatures of complete solidification or commencement of melting.2.386 strbitt -The microstructure resulting from the tempering ofmartensite at about 450C. It is also used to denote fine pearlite which isnot resolved at low magnification.2.381 spalung ( FlakisRg) - su 2.156.2.382 SptrkTttt- A visual test for an approximate estimation of carbonand content of different alloying elements in steel by observing sparks pro.duced by holding a sample against grinding wheel.

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~:1956(PartI)-19762383 special Steel- Steel in the production of which special care hasto be taken so as to attain the desired cleanliness, surface quality and themechanical properties.2L%4 spectroacopy- The test used to 6nd the composition of metals anddoy~ by finding the intensities of standard spectral lines in an instrumentcalibrated with spectroscopic standard materials.2s Spheroiditc ( Spheroidized Cement&) - An aggregate of ironand alloy carbides of essentially spherical shape dispersed throughout amatrix of ferrite obtained by prolonged heating just below ACI, or othermethods of spheriodize annealing.2.3S6 Sphezoidizing- A process of heat treatment to produce globularform of carbide in steel and consists in prolonged heating of steel to a suitabletemperature, within or near the transformation range. This treatmentimproves machinability and facilitates finishing by cold work. It is alsouseful where such structure is desirable for further heat treatment in process-ing certain materials.2.3S7 Spiegeleisen - A ferro-alloy containing carbon between 4 to 6.5per-cent and manganese between 15 to 30 percent ( see IS : llll-1964* ).2LJSS stabilixing- Treatment given to certain materials for such pur-poses as : (a) improved life under service condition, (b) better workability,(c) decreasing age-hardening characteristics at room temperature, and(d) obtaining dimensional stability. This term is also used for inhibitionof weld metal decay in certain varieties of austenitic nickel chrome stainlesssteels by the addition of certain elements, for example, titanium, and niobium( columbium ) .2.3S I Stainless Steel - An alloy steel containing about 12 percent or overof chromium with or without nickel together with other elements, and ischaracterized by its high resistance to corrosive media.2.3 M Steads Brittleness - Brittleness arising from very large grainscaused by incorrect heat treatment of material previously subjected tocritical cold deformation.2.391 Stoviug - See 2.24.2.392 Strain - Deformation caused by stress and expressed as the changeper unit oforiginal dimensions in the test bar under tension or compression.Under shear, the strain is measured by the angular displacement.2.393 Strpin Age Embrittlement - Embrittlement caused by strainag&g and otmm particularly in low carbon steels.

pazikation for spicgcl n (mid).44

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IS:1956(PartI)-19762.394 Strain Age Hardening- Increase in hardness which occurs asa result of strain ageing.2.395 Strrrfn Hardening ( Work Hardening ) - Increase in hardnesscaused by cold-working.2.399 Strasuss Test- A test used to assess the corrosion resistance ofstainless steels.2.397 stress - Load per unit area.2.39S Stress - -Factors, such as abrupt changes ofsection, sharpcorners, sharp fillets, surface crack, etc, which cause concentration of stressat these places.2.399 Stress Relievhg ( Stabilizing ) - Heating to and, if necessary,holding at a sufficiently high temperature below the trans.Gormation range,followed by slow cooling to remove internal stress only. Also calledstabilizing treatment ( see also 2.39S ).2.499 Stre~~Strain Curve -A curve showing the relationship betweenstress and strain ( similar to load-extension curve ).2.491 Swetchtr Strains (Luder Lines) - The roughening and some-what furrowed appearance on the surf&e of low carbon sheets or strips as aresult of uneven spreading in the initial stages of cold-deformation af%erannealing, normalizing or after hot-rolling, though being not so marked inthe last two cases.2.492 Staving - sdd 2.24.2.493 Sub-zero Treatment - Treatment given to certain hardened steelsby cooling to temperatures below zero ( 0C ) to transform any retainedaustenite to martensite.2.494 Sulphur Print Test- A macrographic method of examination,for the distribution of sulphide impurities in steel, in which a sheet of bromidepaper after being soaked in dilute sulphuric acid is placed upon the plainpolished steel surface. The sulphides in steel react with the acid liberatingsulphuretted hydrogen which in turn reacts with the silver salt in the paper,leaving a dark stain, thus indicating the distribution of sulphur and alsoshowing flow lines in forging.2.495 Supe~~ossic Test- Set2.42%.2.466 Tangent3 Test - See2.425.2.497 Temperature/Impact Curve The curve plotted with notchimpact values against corresponding testing temperatures ( see Fig. 15 ).2.499 Temper Brittleness - Notch brittleness to which some alloy steelsare susceptible as a result of tempering within certain temperature range

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Is:1956(P8rtI)-1976220-

200 -

J00TEMPERATURE OF TEST C

FIG. 15 A TYPICAL TBMPERATURE IMPACT CURVEthat is, 350-6OOC, or on slow co&g through this range of temperature aftertempering at hiih temperature.2.409 Temper Carboa- Graphitic carbon resulting from dcsompositionof carbides in ferrous materials.2.410 Temper Colour - Colour developed on the bright steel surface dueto oxide film formation when steels are tempered betwee. 200 to 350C.E&h tempering temperature produces a distinctive colour and hence thelatter is indicative of temperature reached. Time factor also afFixt.s thecolour, so also the steel composition. But with care low alloy and plaincarbon steels give good indication of tempering temperature by the colourdeveloped.

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l9:1956(PmI)-19762.Ul Tanpahg -Heating to elevated temperature but below trans-formation zone, of hardened steels and holding for specified time attemperatures followed by cooling at desired rate to develop desiredmechanicalproper&sin thesesteels.2.412 TemdIe Uremgth-The maximum*load reached in a tensile testdivided by the original cross+ctional area of the gauge length portion ofthetestpiece. Alsotermedas maximum stress or ultimate tensile stress(suFig.3).2.4I9 TamBe Tent-A test in which a standard test piece, gripped atboth ends, s subjected to &&on by load, which is pxgressively increasedtill&actnrctakespbat T&stestisconductedoaglvethefbllowingin-fixln&m(suIs:152I-1974*and IS:l69WS~):

Iimit ofpro~,Yield point,ProofstresUltbnate tensilestress,Percentageelo ng&n, andPercentage eductionofarea.

2.414 Test Piece (TestSpecimem)-Thesampleprepardinaccd-ance with standard dimensions for the purpose of testing, for exam&,tensile test piece ( scpFq. 16 ).2.415 Test 9mqk - Aportionofmaterialsdected knn any bulkconsignment n accordance with the method of sampling at the purptxeofcarryingthe desiredtest.2.416 Thrrrt ~-Stresses developed in a ma&al duringheatingorcoolingasaresultoftanpGnturegradknts.2.417 Tbomns Ruus - & 2.26 and 2.29.2.419Tinah~(htarrrpted a)-Interrupting thequench after a predetermined ime followedby air cooling. Generallythistreatment s empIoyed or reducingdistortionnd toself emperhe har8;medsurfgcewith a view to improving he toughness.2.419 Tokmace Limit - Permissible eviation rom stipulatec* e.~.2.429 Tmsion- Straininga materialby twisting.2.421 Torsiom Test - A test carriedout by twisting a testpiece about itsa~& until fractureoccurs. When the test piece is machined off f&n a bar,

%fcthod or auilc estingrsteel wire (J irJ l vccifier ).tMcthod for tensile testing of steel products (jid remhh).

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I6rl956(PartI)-1976

GAUGE l.EIIjTH GROUND

i iTpp~y

TOT# LENGTHFLAT

FIG. 16 TENSILETEST Pracrsthe practice s to state themaximum stress n shearand the angle of rotation.In tests for wires, the acting length in relation to the diameter and thenumberof wistso be withstood, are specified.2.422 T-e Fraetsut - Fractureacrossthe grains.2.429 Traamfkmadosa Ilrryc (C&icaIRange)-Therange of tem-.perature ver which transfbrmation, hat is, change of phase takes place inthe solid state during heating or cooling.2.424 Trnsui&nTem~ture(BsWeTransWasTeaqe=~e)-When the notched-bar mpact test s carriedout on f&tic steelover a rangeof temperatures,ncludingsub-zero ~mperatures, the fracturechanges ivmductile ( fibrous) to brittle ( crystalhne with progrekve decreasen testingtemperature. The temperatureat which50 percentductile and 50 percentbrittle fracture s obtained, s usually ermed as the transitiontemperatureand is 50 percent of the shelf impact value at the higher temperatures(se8 aLSo2.497).2.429 TB Te&(RadM Test,Tnqes&I T-)--A test forsteel blooms, forgings, sheets,etc, in which thl& IongitudinaI xis of the testpieceisatrightangkstothedirectionofro gorworking. .Intbecaseofforgings,a Wamvemetestmaybespeci6edinacircumferentia,tangential

.

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IS:1956(PartI)-1976or radial direction. In the case of cast iron, it refers to a test used fordetermining the modulus of rupture of a centrally loaded beam test piecesupported at the ends.2.426 True Tam& Stress- Tlie stress load divided by the minimumcross-sectional area of the test piece at the time of racture ) at the time ofCacture.2.427 TlT Cwve - Time-temperature-t curve ( see 2357 ).2.228 B Test ( Sapemodc Temt - A non-destructive test fordetecting internal defects, such as cm+, cavities and unsoundness due todiscontinuities, by the application of high frequency sound waves. Thedetecting instrument transmits such waves through the prepared surthce ofthe material under test and these waves are reflected back by internal flaws.2.429 Upending Test (Jump Test, Knock Down Test, SKIS Test ) -A test to detect surf&e defects on bars, billets, etc, intended for hot- orcold-foging. The test is carried out by hammering or forging the ends ofthe test piece ( hot or cold, as the case may be ) till reduced by a specifiedamount,2.499uphill astiqg - see2.42.2.431Vickers Hardmems est - SGC .119.2.492V-Notch - A notch, in the form of V, made in test pieces for impacttest, the standard notch angle, in the commonly used Izod impact test piece,is 45 with root radius ofO.25 mm.2.433 Wenr Test- A test for determining resistance of a sample to abra-sion under given conditions, such as loading, lubrication, speed, etc.2.434 Weathering Staols -Steels with improved resistance to atmos-pheric corrosion obtained by small additions of copper, phosphorous, chro-mium, etc. Such steels have got characteristic properties and developa thin stable oxide fihn on weathering.2.435 weld Decay- IntercrysUine corrosion which develops in certainaustenitic chromium-nickel steels, which have been heated and/or slowlycooled through the temperature range of 500 to 900C and subjected tochemical attack by certain corrosive agent. It is so called because in awelded structure the zones adjacent to the weld which have been in thistemperature range are liable to fail in this madner.2.436 Weld Daay Teat- A test for determining whether a steel is sus-ceptible to weld decay.2.4~ White ~%st Iran - Cast iron in which all the carbon is in the corn:

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bined state and the fracture is white in appearance ( scd dso 2-a ).

I6:1956(F'art1)-19762.496 hbhemt Mauable cast Iron Acastironmade bypro-loqed annealing of white cast iron, in an oxidizing atmosphere, n whichdecarburization and graphitization take place to eliminate cementite.The carbon that remains sintheformoftempercarbonnodules(~IS:2107~1 362*).2.439WUsmansmarPmemorStrmc~m-AA microstructureindkativeofhighcplltingtemperatureoroverheatinginsolid stateandresults from simultaneousprecipitationof ferrite along difkent planes inthe crystals.2448 wuk 3&&&g-SM2.395.2_m w~a8+-dltestusedfkwin. bkmod+-ipingawire,dr~dspxi6ai~~,diuneta,~~iD6thepacr6rr~~dti?ncs.

INR-AV+CBW&iron~imdddsba_T&~c& * w cz.ggz:thattbetfsqmwc~iits~ktnolartormdaitilaidanditsanl~isntYummcthanpatyarmanypmcesses,~em>249X48y w*-ThetatismedtpevahmequantitativelyWiomphrrqresidUd~, stmctmmofcmmpmmdandtheiridentifica-tion, etc.2.444 Yhldhess-Thcstrcssqtwhichamarked inaclseinstrainoccurswithout an incrcasc in stress duringtensile&E&S.Low carbon steelsusuallyexhibit this phesmmen~2.M Youmg% lMWmms-&m.

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BUREAU OF INDIAN STANDARDSHeadquarters;Manak Bhavan, 9 Bahadur Shah Zafar Marg, NEW DELHI 110002Talephones : 331 01 31, 331 13 75 Telegrams : Manakranrtha( Common to all officer )RcQlonal Oflces TelephonesCentral : Manak Bhrvan, 9 Eahadur Shah Zafar Mrrg, [ 331 01 31NEW DELHI-1 10002 331137s*Eastern : 1 /14 C.I.T. Scheme VI I M V. I. P. Road,Maniktola, CALCUTTA 700054Northarn : SC0 445-446, Sector 35-C,CHANDIGARH 160036Southern : C. I. T. Campus, MADRAS 600113

tWostern : Manakrlaya, E9 MIDC, Marol, Andheri (East),BOMBAY 400093Branch OflcesPushpak Nurmohamed Shaikh Marg, Khanpur,AHMEDABAD 380001SPeenya Industrial Area, 1st Stage, Bangalore Tumkur RoadBAN G.ALORE 560058Gangotri Complex, 5th Floor, Bhadbhada Road, 1. 1. Nagrr,BHOPAL 462003Plot No. 82/83, Lowir Road, BHUBANESHWAR 75100263/5, Ward No. 29, R. G. Barua Road, 5th Byslrne,GUWAHATI 7810036-656C L. N. Gupta Marg ( Nampally Station Rord),HYDERABAD 500001R14 Yudhloter Marg, C Scheme, JAIPUR 302006117/418 B Sarvodaya Nagar, KANPUR 208006Patliputra Industrial Estate, PATNA 800013T.C. No. 14/1421, University P.O., Palayam

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*Sales Office in Calcutta I8 at 5 Chowrlnghee Approach, P.O. PrlncepStrret, Calcutta 700072tSalrr Offlco In Bombay Is at Novrlty Chamber., Grant Road,Bombay 400007SSalrr OPnce In Bangalore IO at Unity Bulldlng, NararimharaJa BquarrBangalore 660002

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6329295

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