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Effective from

May, 2012

Specification No. TI/SPC/OHE/ FASTNERS/0120

GOVERNMENT OF INDIA

MINISTRY OF RAILWAYS

RESEARCH DESIGNS AND STANDARDS ORGANISATION

MANAK NAGAR, LUCKNOW-226011

Specification for Steel, Stainless Steel Bolts, Nuts and Washers for

25 kV a.c. Traction Overhead Equipment

1. SCOPE

1.1 This specification covers the requirements of steel and stainless steel special head /

hexagon straight bolts and screws, flat countersunk nib bolts and screw, U-bolts, J-

bolts, hexagon nuts and lock nuts and plain and spring washers used on 25 kV a.c.

traction overhead equipment. The term fasteners shall include bolts, nuts, and

washer. The term nut shall include lock nuts. The term bolt shall include screws,

special head bolts/screws.

1.2 This specification supersedes RDSO Specification No. ETI/OHE/18(4/84) with

A&C Slip No. 1 to 5.

2. GOVERNING SPECIFICATIONS:

2.1 The fasteners shall generally conform to the respective Indian Standards unless

specified otherwise herein. The provisions of the governing specifications shall be

applied in the manner altered/amended or supplemented by this specification.

2.2 In preparation of this specification reference has been made to the following

specifications.

i) IS: 1363-2002 Black hexagon bolts nuts and lock nuts

(Dia 6 to 39) & black hexagon screws

(Dia 6 to 24 mm).

ii) IS: 1367 (Pt.2, 3, 5, 6, 7, 9,

10, 13, 18).

Technical supply conditions for threaded

Steel fasteners

iii) BS: 6105-1981 Corrosion resistant stainless steel

fasteners

iv) IS: 1570 (Pt. 5) – 1985 Schedule for wrought steels (Stainless &

heat resisting steels)

v) BS: 970: Pt.4 – 1970 Wrought steels (Stainless, heat

resisting and valve steels).

vi) IS: 2016- 1967 Plain washers

vii) IS: 3063 – 1994 Spring washer for bolts, nuts &

screws.

viii) BS: 2061 – 1953 Phosphor bronze spring washer for

General engineering purposes.

ix) IS: 549 – 1974 Split pines.

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x) IS: 9549 – 1980 Dimension for split pin holes, wire

holes and head slots for bolts.

xi) IS: 9519 – 2005 Dimensions for width across flats for

hexagon head bolts & nuts.

xii) IS: 8353 – 1977 Flat countersunk nib bolts.

xiii) IS: 730 – 1978 Hook bolts for corrugated sheet roofing.

xiv) IS: 1368 – 1987 Dimensions for ends of bolts and screws.

xv) IS: 4172 – 1987 Dimension for radii under the head of

bolts and screws.

xvi) IS: 5369 – 1975 General requirements for plain washers

and lock washers.

xvii) IS: 4206 – 1987 Dimensions for nominal lengths and

thread lengths for bolts screws and studs.

xviii) IS: 4213 – I, II, III, IV, V ISO metric screws threads.

xix) IS: 2334 – 2001 Gauging practice for ISO metric screw

threads.

xx) IS: 1369 – 1995 Dimensions for screw thread run out

sand undercuts.

xxi) IS: 2614 – 1969 Methods for sampling of fasteners

xxii) IS: 2629 – 1985 Recommended practice for hot dip

galvanizing of iron and steel.

xxiii) IS: 4211 – 1993 Thread pitch gauges for ISO metric

screws threads ( Pitch range 0.25 to 6.0

mm ).

xxiv) IS: 6745 – 1972 Methods for determination of mass of

zinc coating on zinc coated iron &

steel articles.

xxv) IS: 2633 – 1986 Method for testing uniformity of coating

on zinc coated articles.

xxvi) IS: 9141 – 1979 Code of practice for packing of fasteners

xxvii) IS: 3203 - 1982 Methods of testing local thickness of

electroplated coatings.

3. DEVIATION FROM SPECIFICATION:

3.1 Any deviation from this specification calculated to improve the performance,

efficiency and utility of fasteners proposed by the tenderer will be given due

consideration provided full particulars with justification thereof are furnished.

4. SERVICE CONDITIONS:

4.1 The fasteners are used in conjunction with various fittings/components of traction

overhead equipment including those carrying current.

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4.2 Weather conditions : The weather conditions under which the fasteners are used

vary widely. The limiting conditions which have to be withstood in service are

indicated below :

-- Max. temperature of air in shade - 45° C

-- Min. temperature of air in shade - 0° C

-- Max. temperature attainable by an - 65.5° C

object exposed to sun.

-- Max. relative humidity - 100%

-- Average annual rainfall - 1750 to 6250 mm

-- Average number of dust - 35 days. Max.

Storm days per annum

-- Number of thunder storm days - 35 days Max.

per annum.

-- No. of rainy days per annum - 120 days Max.

-- Maximum wind pressure - 200 Kg/Sq. meter.

- Altitude - Not exceeding 1000 m.

4.3 The fasteners are also subjected to chemical pollution from the effluent gases of

chemical plants, exhaust of steam/diesel locomotives and to saline atmosphere in

coastal areas.

5. MATERIAL

5.1 Ferrous fasteners : Steel bolts/screws/nuts shall conform to Grade-C specification in

IS: 1367 (Part 2) – 2002. Bolts/Screws shall comply with mechanical property

class 4.6 of IS: 1367 (part 3) – 2002. Nuts shall comply with the mechanical

shall comply with mechanical property class 4.6 of IS:1367(Part 3) -2002. Nuts

all comply with the mechanical property class 04, 4 or 5 (as applicable) of IS:1367

(Part 6) – 1994.

5.2 Stainless steel fasteners : The stainless steel bolts and nuts shall conform to property

Class 50 (austenitic group) of BS:6105-1981. The stainless steel of bolts, nuts and

washers shall conform to Grade A1 (austenitic group) of BS: 6105-1981 with 10%

Ni and 0.5-0.6% Mo or grade 316 S 16 of BS: 970: (Part 4)-1970. These grades are

equivalent to AISI grades 302 (with 10% Ni and 0.5-0.6% molybdenum) and 316

respectively.

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5.3 Plain washers: Plain washers shall conform to IS: 2016 – 1967. Galvanized steel

plain washers (Punched, type A) shall be used with galvanized steel bolts; and

bronze, stainless steel or copper washers (punched type A) with stainless steel

bolts.

5.4 Spring washers: The spring washers shall conform to IS: 3063 – 1994. Galvanized

steel spring washers with flat ends (type B) shall be used with galvanized steel

bolts. Phosphor bronze spring washers conforming to BS: 2061– 1953 shall be used

with stainless steel bolts.

6. GENERAL REQUIREMENTS :

6.1 Workmanship: The bolts and nuts shall be clearly finished, sound & free from

defects which may effect their serviceability, and shall be consistent with the grade

prescribed. The fasteners shall have full surfaces and edges in keeping with the

method of manufacturing used. These shall be free from burrs although barely

perceptible thin burrs which results for example, from slotting and trimming

operations, may be left out. The Black Grade bolts may have reasonable die – seem

on the shank; but in no case the shank diameter with such seams shall exceed the

maximum permissible diameter. Stainless steel fasteners shall have bright finish.

The washers shall be free from cracks, burrs, pits and other defects. The holes of

plain washers shall be reasonably concentric with the outer periphery. All sharp

edges shall be removed. Spring washers shall be supplied in natural finish. The

surfaces of washers shall be free from die marks and shall be finished smooth. The

ends shall be so severed as to prevent tangling.

6.2 Bolts end nuts shall be classified by their nominal diameter. The dimensions of

hexagons, chamfers, shank diameter and other dimensions for different nominal

sizes of bolts and nuts, whether ferrous or stainless steel shall be in accordance with

Table 1.

6.3 Unless otherwise shown in the purchaser‟s drawings, the nuts shall have single

chamfer, and lock nuts shall have double chamfer.

6.4 Bolts shall be drilled for split pins wherever shown in the purchaser‟s drawings.

Split pin holes shall be at right angles to the axis of bolts. The dimensions for split

pin holes for a particular size of split pin shall be according to IS: 549 – 1974.

6.4.1 The tolerance in the location of split pin holes shall be according to

IS: 9549 – 1980.

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7. DIMENSIONS:

7.1 The dimensions for hexagon bolts, screw and nuts shall be in accordance with

Table 1 read in conjunction with the relevant purchaser‟s drawings and IS:9519 –

2005 “Specification for modified dimensions of width across flats for hexagonal

bolts / screws and nuts normal series”.

7.2 The dimensions for special head bolts and screws, U–bolts, J-bolts shall be as

shown in the purchasers drawings.

7.3 Dimensions of flat countersunk nib bolts/screws shall conform to IS: 8353 – 1977

and those of J bolts shall conform to IS:730 – 1978.

7.4 Dimensions of ends of bolts and screws shall be as per IS: 1363 – 2002 and the

dimensions for radii under the head of bolts and screws shall be as per IS: 4172 –

1987. The cone point/ turncated cone point ends of bolts and screws shall be as

shown in purchaser‟s drawings.

7.5 Dimensions of plain and spring washers shall be as shown in IS:2016 -1967 and IS:

3063-1994 respectively. The permissible deviations from dimensions of plain

washers shall be in accordance with table 3 and 4 of IS: 5369 -1975.

7.6 The dimensional tolerances for galvanized steel and stainless steel bolts, screws

and nuts shall be as per Table 1.

8. LENGTHS AND THREADED LENGTHS:

8.1 The lengths and threaded lengths of bolts / screws shall be generally as per IS: 4206

– 1987. However, exact lengths and threaded lengths shall be as shown in

purchaser‟s drawings.

9. THREADS (INTERNAL AND EXTERNAL)

9.1 The threads shall be ISO metric. The internal and external thread profile shall be in

accordance with IS : 4213 (Part I) – 1976.

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9.2 The diameter and pitch and combination shall be according to IS: 4213(Part II)-

1976. The pitch shall be coarse.

9.3 The basic dimensions for profiles of ISO metric screw threads shall be as per IS:

4213 (Part III) – 1976.

9.4 The tolerance class for ISO metric screws threads shall be coarse as given in table 5

of IS:4213(Part IV)-1976.

9.5 The deviations from basic dimensions for nut and bolt threads of the tolerance class

specified in clause 9.4 shall be as tabulated in table – 1. The tolerance class shall be

7H for nuts and 8g for bolt threads. The limits of sizes for tolerance class 7H for

nut threads and 8g for bolt threads are given in table-1. These limits are applicable

to ferrous fasteners in black condition and to stainless steel fasteners in finished

condition.

9.6 The thread run outs and undercuts shall be as per IS: 1369-1995.

10. GALVANIZING OF FERROUS FASTNERS::

10.1 Dimensions:

10.1.1 Fasteners with internal Threads –Prior to galvanizing and subsequent tapping the

dimensions of fasteners with internal threads shall conform to the relevant

standards. Internal threads shall be tapped over-size after galvanizing and they shall

be oiled for corrosion protection.

10.1.1.1 The oversize tapping allowance shall be as given in Table below. These

allowances are applicable to major, pitch and minor diameters, the amended

diameters being subject to the same manufacturing tolerances of the appropriate

grade of threads stated in the relevant fastener standard.

TABLE: ALLOWANCES FOR INTERNAL THREADS TO

ACCOMMODATE GALVANIZED EXTERNAL

THREADS.

Nominal Size Internal Diametral Allowances

Threads. mm

Below M16 +0.40

M16 to M22 +0.50

Over M22 and

up to and including M36 +0.65

10.1.2 Fasteners with External Threads – Prior to galvanizing, the dimensions of

fasteners with external threads shall conform to the relevant standards including

thread sizes.

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10.1.2.1 The thickness of galvanized coating on external threads shall be so controlled in

the galvanizing process that galvanized fasteners with external threads can be

assembled by hand with internally threaded fasteners complying with 10.1.1.

10.1.2.2 Galvanized external threads shall not be re-cut.

10.1.3 Coating Requirements:

10.1.3.1 Mass of Coating - The mass of coating per square meter of the surface shall

comply with the minimum average and minimum individual sample coating

given in Table below. The mass of coating shall be determined by one the

following methods:

a) The stripping test described in Append-ix B; or

b) Magnetic or electronic thickness measuring devices as covered in IS:

3203-1965 „Method of testing local thickness of electroplated coatings‟.

The mass of coating in g/m2

is found by multiplying the thickness in

Micrometers by 7.0.

10.1.3.2 In case of dispute, the stripping test shall be the referee test.

TABLE: MASS AND EQUZAVALANT THICKNESS OF COATING

Minimum Average Minimum Individual

Mass Thickness Mass Thickness

g/m2 µm g/m

2 µm

375 54 300 43

10.1.4 Uniformity of Coating – The uniformity of zinc coating shall be such that the

coating shall withstand the copper sulphate test as given in IS : 2633- 1986.

‟Methods of testing uniformity of coating on zinc coated articles (first revisions )

„without showing any adherent red deposit of metallic copper upon the base metal

with the following exceptions.

a) A fine line of copper on the crest of the screw threads or on sharp edges of

bolt/nut or at or adjacent to any cut of abrasion present in the original

fastener shall not be considered a defect to cause rejection, and

b) Any deposit of metallic copper with threads of fasteners which have been re-

thread rolled after galvanizing, is allowable.

10.1.5 Adhesion of Coating - The coating shall withstand the knife test as covered in IS:

2629-1985.

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10.2 All ferrous fasteners including washers shall be hot dip galvanized for electro-

galvanised to achieve a uniform adherent coating of zinc. The minimum

thickness of zinc coating shall be of 400 g/m2 (55 microns)”.

11. TESTS

11.1 The manufacturers shall carry out the specified tests, during production on the

samples, taken at regular intervals, separately for the different sizes, grade &

material, which are being manufactured under similar processes of productions to

ensure conformity to relevant specifications as also to maintain proper control over

the process of manufacture. The manufacturer shall at the time of inspection,

produce a certificate showing the records of various inspections / tests which have

been exercised during manufacture.

11.2 When the purchaser requires additional tests, related to his order but not specified

hereunder, such tests shall be subject of agreement between the purchaser and the

manufacturer.

11.3 All the tests on the fasteners shall be carried out at manufacturers works. The

manufacturer shall arrange, without making claim or charge, all the necessary

machinery, apparatus, labour, assistance etc. required to get the prescribed tests

conducted in the presence of purchaser‟s representative.

11.4 Type tests : -

i) Visual examination ( 12.1)

ii) Measurement of dimensions (12.2)

iii) Gauging of threads ( 12.3)

iv) Chemical composition (12.4)

v) Mechanical tests (12.5)

a) Tensile test (12.5.1)

b) Elongation after fracture (12.5.2)

c) Hardness test (12.6)

d) Proof load test (12.7)

(for ferrous bolts and nuts

and stainless steel nuts).

e) 0.2% permanent strain test (12.8)

(For S.S. bolts only)

f) Head soundness test ( 12.9)

g) Crushing test on nuts (12.10)

(SS nuts only)

h) Bend test on straight bolts (12.11)

(SS bolts only).

i) Torsion test on bolts & nuts (12.12)

(for SS bolts & nuts only)

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vi) Galvanizing test on ferrous fasteners (12.13)

vii) Inter-crystalline corrosion bend test (12.14)

for SS fasteners, or Micro examination of

SS fasteners (12.15)

viii) Permanent set test on spring washers (12.16)

ix) Twist test on spring washers (12.17)

11.5 Routine tests

Visual examination (12.1)

11.6 Acceptance tests

i) Visual examination ( 12.1)

ii) Measurement of dimensions (12.2)

iii) Gauging of threads (12.3)

iv) Chemical composition (12.4)

( only for stainless steel fasteners)

v) Mechanical tests (12.5)

a) Tensile test (12.5.1)

b) Percentage elongation after fracture (12.5.2)

c) Hardness test (12.6)

d) Proof load test (12.7)

(for ferrous bolts & nuts and for stainless steel nuts).

e) Stress at 0.2% permanent strain test (12.8)

f) Head soundness test for bolts (12.9)

g) Crushing test on nuts (12.10)

(SS nuts only)

h) Bend test on straight bolts (12.11)

( SS bolt only)

i) Torsion test on bolts & nuts (12.12)

(for SS bolts & nuts only)

vi) Galvanizing test on ferrous fasteners (12.13)

vii) Inter-crystalline corrosion bend test on (12.14)

stainless steel fastners.

Or

Micro examination of stainless steel (12.15)

Fasteners.

viii) Permanent set test on spring washers (12.16)

ix) Twist test on spring washers(12.17)

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11.6.1 Sampling procedure :

11.6.1.1 Lot : All the fasteners in a consignment belonging to the same size, grade ,

material and manufactured under similar process of production and submitted for

inspection at one instance shall constitute a lot.

11.6.2 Scale of sampling :

11.6.2.1 Samples shall be selected at random and examined for each lot separately for

ascertaining their conformity to the requirements of this specification. Only one

set of samples as indicated in 11.6.2.2 shall be drawn from a lot for all the

characteristics.

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TABLE 2

SCALE OF SAMPLING AND CRITERIA FOR CONFO RMITY FOR INSPECTION

( Clause 11.6.1, 11.6.2, 11.6.3 )

Note:- Classification of major and minor defect is given in Appendix A of IS: 2614 – 1969. [ LEGEND + AQL= Acceptable quality Level ]

Lot

size

VISUAL CHARACTERISTICS DUDS DIMENSIONAL CHARACTERISTICS STAINLESS STEEL

FASTERNERS

Sample Sample

size

Cumulative

size

A

C

Re Ac Re Sample Sam

ple

size

Cumul

ative

size

BLACK FASTNERS

Ac Re |

Ac Re

2.5 |

4.0

Major defect

Ac | Re

1.5

Major

defect

Ac |

Re

2.5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Upto

100

First

Second

20

20

20

40

1

4

4

5

0

1

2

2

First

Second

8

8

8

16

0

1

2

2

0

1

2

2

0

1

2

2

0

1

2

2

101”3

00

First

Second

32

32

32

64

2

6

5

7

0

1

2

2

First

Second

13

13

13

26

0

1

2

2

0

3

3

4

0

1

2

2

0

1

2

2

301”5

00

First

Second

50

50

50

100

3

8

7

9

0

1

2

2

First

Second

20

20

20

40

0

3

3

4

1

4

4

5

0

1

2

2

0

3

3

4

501”1

000

First

Second

80

80

80

160

5

12

9

13

0

3

3

4

First

Second

32

32

32

64

1

4

4

5

2

6

5

7

0

3

3

4

1

4

4

5

1001”

3000

First

Second

125

125

125

250

7

18

11

19

1

4

4

5

First

Second

50

50

50

100

2

6

5

7

3

8

7

9

1

4

4

5

2

6

5

7

3001”

10000

First

Second

200

200

200

400

11

26

16

27

2

6

5

7

First

Second

80

80

80

160

3

8

7

9

5

12

9

13

2

6

5

7

3

8

7

9

10001

”3500

0

First

Second

315

315

315

630

11

26

16

27

3

8

7

9

First

Second

125

125

125

250

5

12

9

13

7

18

11

19

3

8

7

9

5

12

9

13

Over

35000

First

Second

500

500

500

1000

11

26

16

27

5

12

9

13

First

Second

200

200

200

400

7

18

11

19

11

26

16

27

5

12

9

13

7

18

11

19

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11.6.2.2 Samples shall be drawn from each lot in accordance with Cols. 1, 2,3 of table 2

for visual and dimensional verifications and for inspection of physical and other

properties.

11.6.3 Criteria for conformity

11.6.3.1 Visual characteristics : All the fasteners drawn in accordance with clause 11.6.2.2

shall be first examined for visual characteristics like type, finish, workmanship,

duds, visual surface discontinuities and identification mark. To ascertain the

conformity of the lot to the requirements of all visual characteristics, except duds,

the procedure given in 11.6.3.1.1 shall be followed. For duds, procedure given in

11.6.3.1.2 shall be followed.

11.6.3.1.1 Visual characteristics ( other then duds) : If in the first sample the number of

defective fasteners with respect to all visual characteristics, except duds, is less

than or equal to the corresponding acceptance number ( Ac) given in Col.5 of

table 2 the lot shall be declared as conforming to the requirements for these

characteristics. If the number of defectives is greater then or equal to the

corresponding rejection number (Re) given in Col.6 of table 2 the lot shall be

deemed as not meeting the requirements for these characteristics. If the number of

defectives is greater than the acceptance number but less than the rejection

number a second sample of the same x number of fasteners selected as the first

sample shall be taken to determine the conformity or otherwise of the lot. The

number of defectives found in the first and second sample shall be combined and

if the combined number of defectives is less than or equal to the corresponding

acceptance number the lot shall be declared as conforming to the requirements;

otherwise not.

11.6.3.1.2 Duds : If the number of defective fasteners in respect of duds is less than or equal

to the corresponding acceptance number given in col.7 of table 2, the lot shall be

declared as conforming to the requirements for duds. If the number of defective

fasteners is greater than or equal to the rejection number given in col.8 of table 2,

the lot shall be declared as not conforming to the requirements for duds. If the

number of defective fasteners is greater than the acceptance number but less than

the rejection number, a second sample of the same number of fasteners selected as

the first sample shall be taken to determine the conformity or otherwise of the lot.

The number of defective fasteners found in the first and second samples shall be

combined and if the combined number of defective fasteners is less than or equal

to the corresponding acceptance number, the lot shall be declared as conforming

to the requirements for duds, otherwise not.

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11.6.3.2 Dimensional characteristics : The lot which has been found satisfactory in respect

of visual characteristics ( See 11.6.3.1 ) shall be tested for dimensional

characteristics like diameter, length etc. except pitch, basic dimensions of threads

which will be tested as per clause 12.3 after stripping / case of ferrous fasteners.

The fasteners for this purpose shall be taken at random in accordance with col.9

and 10 of table 2, from those already drawn for inspection of visual characteristics

( see 11.6.3.1) and tested for dimensional characteristics. If the number of

fasteners failing to satisfy the requirements for these characteristics is less than or

equal to the corresponding acceptance number given in col. 12,14,16 or 18 of

table 2, the lot shall be declared as to have not the requirements of the

specification in respect of these characteristics. If the number of defectives is

greater than or equal to the corresponding rejection numbers given in col.

13,15,17 or 19 of table 2 the lot shall be deemed as not confirming to these

characteristics. In case the number of defective lies in between the acceptance and

rejection number, a second sample of the same size shall be taken and inspected

for dimensional characteristics and inference drawn accordingly.

11.6.3.3 Physical chemical & galvanising requirements :

11.6.3.3.1 From the samples taken in accordance with 11.6.2.2 end which have been

subjected to the visual and dimensional tests, samples in multiples of 5 or 6, as the

case may be shall be drawn at random for mechanical, chemical and galvanizing

tests in case of bolts and nuts. In case of spring washers, samples in multiples of 4

shall be selected for twist test and permanent set test.

11.6.3.3.2 Galvanized fasteners :

i) BOLTS : - The samples selected in accordance with clause 11.6.3.3.1 shall

be divided in 6 equal parts. Each part shall be subjected to one of the

following tests:

a) Tensile / elongation test ( Cl.12.5.1 and 12.5.2 )

b) Proof load test (Cl.12.7)

c) Head soundness test ( Cl. 12.9)

d) Hardness test ( Cl.12.6)

e) Galvanizing test ( Cl.12.13)

f) Gauging of threads ( Cl. 12.3)

and visual examination after stripping ( 12.1)

ii) NUTS : - The samples selected in accordance with clause 11.6.3.3.1 shall be

divided into 4 equal parts. Each part shall be subjected to one of the

following tests.

a) Proof load test ( 12.7)

b) Hardness test (12.6)

c) Gauging of threads (12.3)

d) Galvanizing test and visual examination.

after stripping ( 12.13 & 12.1 )

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11.6.3.3.3 Stainless steel fasteners :

(i) BOLTS : - The samples selected in accordance with clause 11.6.3.3.1 shall be

divided in 6 equal parts. Each part shall be subjected to the following tests:

a) Tensile strength / Extension ( 12.5.1 & 12.5.2)

b) Stress at 0.2% permanent strain ( 12.8)

c) Head soundness test (12.9)

d) Bend test (12.11)

e) Gauging of threads end Torsion test ( 12.3 & 12.12)

f) Micro examination, hardness & Chem.

Composition ( 12.15, 12.6 & 12.4 )

ii) NUTS : - The samples selected in accordance with clause 11.6.3.3.1 shall be

divided into 4 equal parts. Each part shall be subjected to following tests.

a) Proof load test ( 12.7)

b) Gauging of threads and Crushing test ( 12.3 and 12.10)

c) Micro examination ( 12.15 )

d) Chemical composition (12.4)

e) Hardness test (12.6)

11.6.3.3.4 Should more than one sample fail in any test(s), the lot shall be rejected. If only one

sample fails in any test, twice the number of samples shall be drawn and the test,

twice the number of samples shall be repeated. The lot shall be accepted if there is

no failure in the re-test.

12. METHOD OF TESTS:

12.1 Visual Examination : All the bolts & nuts shall be visually examined for finish,

workmanship, chamfers and identification mark and for visual surface

discontinuities referred in IS: 1367 (Part 9) – 1993 and IS: 1367(Part.10) – 2002.

Stainless steel fasteners shall be examined for bright finish also. The bolts shall be

examined for straightness of shank and for any eccentricity of shank with respect to

head. Nuts & washers shall be examined for eccentricity of the holes, crack, burrs,

pits and other defects. Zinc coating on ferrous fasteners shall be examined for

defects defined in Appendix A of IS: 2629 – 1985.

12.2 Measurement of dimensions : The dimensions of fasteners including lengths and

threaded lengths of bolts shall be measured with the help of suitable gauges/devices

and shall be within the limits specified in clause 7 & 8 of this specification or these

specified in purchaser‟s drawings.

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12.3 Gauging of threads: These tests shall be done in black condition of galvanized

fasteners after stripping. The thread pitch for particular diameter combination ( See

Table 1 of IS:4213 (Part –II - 1976) and table 1) shall be measured with the help of

thread pitch gauges conforming to IS:4211-1993. The thread profile shall be checked

with the help of gauges in accordance with IS: 2334-2001. The limits of sizes of nut

and bolt threads for tolerance class7H and 8g respectively are specified in Table -1.

12.4 Chemical composition

12.4.1 Ferrous fasteners: Chemical analysis of the galvanized steel bolts shall be carried out

in accordance with IS: 228 1987 and parts and shall conform to Clause 4 of IS :

1367(Part 3) – 2002 i.e. Carbon shall not exceed 0.55%, sulphure 0.06% and

phosphorus 0.05% for bolts. The chemical composition for ferrous nuts shall be as

follows:

Property Class C Mn P S

%Max. %Min. %Max. %Min.

4,5 0.50 - 0.110 0.150

04 0.53 0.25 0.060 0.150

12.4.2 Stainless steel fasteners shall be analyzed in accordance with IS: 228-1987 and parts.

The chemical composition shall conform to Grades Mentioned clause 5.2.

12.5 Mechanical Tests

12.5.1 Tensile test for bolts:

12.5.1.1 G.S. Bolts: The tensile test shall be carried out on all sizes of bolts in finished

condition where a. free threaded length equal to one diameter of bolt shall also be

subjected to tensile load. The fracture shall occur in the shank or thread of bolt and

not at the junction of the head and the shank. The calculation of the tensile strength is

based on the stress area. The tensile strength shall not be less than 400 N/mm2.

12.5.1.2 Stainless steel bolts and studs: The tensile test shall be carried out on all sizes of bolts

and studs in finished condition where a free threaded length equal to one diameter of

bolt shall also be subjected to tensile load. The fracture shall occur in the shank or

thread of bolt and not at the junction of the head and the shank. The calculation of the

tensile strength is based on the stress area. The tensile strength shall not be less than

500 N/mm2.

12.5.13 Test rig: For the purpose of tensile test the rig shall be designed accordingly. The

speed of testing shall not exceed 25 mm/min. The grips of testing machine should be

self aligning to avoid side thrust on the specimen".

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12.5.2 Determination of percentage elongation after fracture:

12.5.2.1 G.S. bolts: The elongation test shall be carried out on full size bolts in finished

condition where it is possible to mark the gauge length equal to 5.65 √So on the shank.

Where it is not possible to mark the gauge length on the shank, machined test pieces

shall be used for the purpose of determination of percentage elongation after fracture

as per clause 8.1 IS:1367 (Part 3):2002. The load shall be applied in the manner as in

12.5.1.3. The elongation after fracture in both the cases shall not be less than 22%. The

applicability of the elongation test on the full size bolts in finished condition and on

machined test pieces (refer Drg. No. ETI/C/0073 Mod. A) Shall be as under:-

Nominal thread /

shank diameter

(mm)

Dimensions for bolts as per Drg. No. ETI/C/0073 Mod. A

Machined test pieces In finished condition.

12 60/30 and below 120/36 and above.

14 All sizes


18 All sizes


24 All sizes

12.5.2.2 Stainless steel bolts and studs: The extension after fracture of stainless steel bolts and

studs shall be measured during the tensile test (see sub- clause 12.5.1.2). The extension

shall not be less than 0.6 d (where d is nominal diameter of bolt).

12.6 Hardness Test :

12.6.1 Hardness test for galvanised steel fasteners shall be carried out after removal of zinc

coating. On steel bolts, the test shall be carried out in accordance with Clause 8.4 of

IS:1367(Part 3)-2002 and on steel nuts in accordance with Clause 8.2 of

IS:1367(Part.6)-1994. On stainless steel bolts and nuts this test shall be carried out in

accordance with Clause 6.7 of BS: 6105-1981. The values of hardness shall be within

the ranges given in Table 3 below. ”

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Table 3

Fastener

Property

class

Nominal size Hardness

Minimum Maximum

Steel Bolts 4.6 All 120 HV 220 HV

Steel Nuts 04 All 188 HV 302 HV

4 Over M16 to M39 117 HV 302 HV

5 M10 – M 16 130 HV 302 HV

Over M16 to M39 146 HV 302 HV

Stainless steel

bolts & nuts

- All - 183 HB

12.7 Proof load test on bolts and nuts :

12.7.1 Proof load test on bolts and nuts shall be carried out in accordance with Clause 8.5 of

IS:1367 (Part 3) - 2002 and Clause 8.1 of IS:1367 (Part.6)-1994 respectively. The steel

bolts shall be capable of being fully loaded upto the proof load, as prescribed in Table 4.

Steel and stainless steel nuts shall be capable of being fully loaded upto proof loads

indicated in Table 5.”

Table 4 - PROOF LOADS FOR STEEL BOLTS ISO METRIC COARSE TIREAD

Nominal Pitch Nominal Property class

Thread of the Stress

--------------------------------------------------------------------------------------

Diameter Threads Area 4.6

mm mm mm2 Proof load N

6 1 20.1 4520

7 1 28.9 6500

8 1.25 36.6 8240

10 1.5 58.0 13000

12 1.75 84.3 19000

14 2 115 25900

16 2 157 35300

18 2.5 192 43200

20 2.5 245 55100

22 2.5 303 68200

24 3 353 79400

27 3 459 103000

30 3.5 561 126000

33 3.5 694 156000

36 4 817 184000

39 4 976 220000

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TABLE 5 – PROOF LOAD VALUES FOR NUTS – ISO METRIC COARSE TIREADS

Nominal Pitch of the Nominal Proof load N_____________

Size thread mm stress area Steel Nuts Stainless steel

of Mandrel nuts,(proof

stress500

N/mm2)

mm2 Property Property Property

Class04 Class 4 Class5

M6 1 20.1 7640 ---- 11700 10000

M7 1 28.9 11000 ---- 16800 14500

M8 1.25 36.6 13900 ---- 21600 18300

M10 1.5 58 22000 ---- 34200 29000

M12 1.75 84.3 32000 ---- 51400 42200

M14 2 115 43700 ---- 70200 57500

M16 2 157 59700 ---- 95800 78500

M18 2.5 192 73000 97900 121000 96000

M20 2.5 245 93100 125000 154400 122500

M22 2.5 303 113100 154500 190900 152000

M24 3 353 134100 180000 222400 476500

M27 3 459 174400 234100 289200 229500

M30 3.5 561 213200 286100 353400 280500

M33 3.5 694 263700 353900 437200 347000

M36 4 817 310500 416700 514700 408500

M39 4 976 370900 497800 614900 488000

12.8 Stress at 0.2% permanent strain test:(for stainless steel bolt only)

12.8.1 This test shall be conducted in accordance with clause 6.3 of BS:6105 –1981. The

stress at 0.2% permanent strain shall not be less then 210 N/mm2.

12.9 Head soundness test for bolts:

12.9.1 This test is not applicable to U bolts, J bolts and flat countersunk nib bolts..

12.9.2 This test shall be carried out as illustrated in figure 2 (enclosed) and in Fig. 4 of

IS:1367(Part-3)-2002.

12.9.3 The bolt shall be inserted in a special steel die of the dimensions given in Table II of

IS:1367(Part-3)-2002. The hole in the die shall be at an angle of 600 to its upper

surface.

12.9.4 When struck several blows with a hammer the head of bolt or screw should be bent to

an angle (90-60)0 without showing any sign of cracking at the fillet between shank and

head.

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12.9.5 Where screws are threaded upto the head the test will be regarded as established even if

a crack should appear in the first thread, provided that head does not snap off.

12.10 Crushing test on nuts : ( Stainless steel only)

12.10.1 The nut under test shall be placed edgewise on an anvil and crushed by hammering till

its threads come in contact with a mandrel, the diameter of which shall be 0.9 D1 where

D1 is the minor diameter of nut described in figure 1 of IS:4213(Part.I):1976. After

crushing, the nut shall not exhibit any fracture or crack at any point. The nut may then

be broken for further chemical analysis and inspection of structure.

12.11 Bond test on straight bolts : ( Stainless steel only)

12.11.1 This test is applicable only to straight bolts.

12.11.2 The threaded part of the bolt shall be so held in the jaws of a vice that the threaded part

projects for a distance equal to at least half the nominal diameter. The projecting part

shall then be bent by hammering so that the axis of free portion is at an angle of 165

degree to the axis of the portion held in the vice. On examination, the bend shall not

exhibit any crack (see fig.3).

12.12 Torsion test on bolts and nuts ( For stainless steel bolts & nuts only )

12.12.1 A torsion test shall be conducted on stainless steel bolts and nuts. The test shall be

conducted as described in 12.12.2 in case of straight bolts and as described in 12.12.3 in

case of U bolts. The ultimate torsional strength shall be not less than that specified in

table 6.

TABLE – 6

ULTIMATE TORSIONAL MOMENT FOR

STAINLESS STEEL BOLTS AND NUTS

Diameter of Ultimate torsional strength (Min.)

bolt . (kg-m) .

10 6.5

12 12

14 16

12.12.2 The head of the bolt shall be gripped in a vice and a steel plate slipped over the thread,

the diameter of the hole drilled in this steel plate being 11 mm in case of 10mm diameter

bolts, 14 mm in case of 12 mm diameter bolts and 16 mm in the case of 14 mm

diameter bolts. A flat steel washer is then placed between the steel plate and the nut (but

none between plate and head of bolt). The total thickness of the steel plate and the

washer shall be so chosen that the position of nut on the threaded portion of bolt is the

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same as when the bolt is in actual use. The test shall be carried out without lubrication of

the parts in contact with each other. The torque shall be applied by means of torque

spanner, the design of which is subject to the approval of the purchaser. The torque shall

be increased in steps until the bolt fractures. After each increment of torque, the nut shall

be unscrewed and the threads on both bolt and nut examined.

12.12.3 The torsion test on U bolts shall be conducted in a manner similar to that described in

12.12.2, but the U bolt shall be prevented from deforming in the course of the test by

seating it on a mandrel, the radius of curvature of which is equal to that of the inner edge

of the U bolt. A steel plate with two drilled holes shall be slipped over the two limbs of

the U bolt, the diameter of the holes in the steel plate bearing the same relationship to

the diameter of the bolt as in the case of straight bolts. The steep plate may be integral

with the mandrel. A flat steel washer shall then be placed between the steel plate and the

nut on each limb(Fig 4). The torsion test shall then be carried out as described in 12.2.2

after gripping the mandrel in a vice. It is sufficient if the test is conducted on one limb of

the U-bolt.

12.12.4 The test shall result in fracture of the bolt, but not of the nut. The values of torque at

fracture shall be not less then that indicated in Table-3. further, on unscrewing the nut at

any value of torque below the value specified in table 3, the threads on bolt and nut shall

be found to be undamaged and it shall be possible to work the nut along the entire

threaded length of the bolt.

12.13 Galvanizing test :-The zinc coating on galvanized fasteners shall be tested for adherence,

uniformity and mass. The mass of zinc coating shall be measured on the unthreaded

portion by stripping method (IS:6745 -1972) or by previously calibrated elcometer (

magnetic method). The uniformity shall be checked by Preece test( IS:2633-1986) on

the threaded portion of bolts. It shall withstand at least five one minute successive dips.

Adherence shall be checked on the shank or head by any one of the methods prescribed

in clause 6.4 of IS 2629-1985.

12.14 Inter-crytallic corrosion bend test ( For stainless steel only )

12.14.1 The bend test pieces shall not be larger than 12.5 mm (1/2 inch) diameter. The test piece

shall be sensitized by heating to a temperature of 6500C for the period stated in the

relevant material specification, followed by cooling in air. All test pieces shall be

immersed for 72 hours in boiling solution having the following composition:

111 g copper sulphate ( CuSo4.5 H2O), 98 g

Sulphuric acid ( relative density (d) = 1.84)

and made upto 1 litre with distilled water.

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Precautions shall be taken during the boiling to prevent concentration of the solution due

to evaporation.

After this preparation each test piece shall be bent through 90° round a radius equal to

three times the diameter and thickness of the test piece, and shall withstand this

treatment without cracking on the outer, convex surface.

12.15 Micro examination of stainless steel fasteners:

(Test for freedom from carbide precipitation):

12.15.1 Micro examination on transverse section of stainless steel bolts and nuts shall be carried

out to ascertain freedom from carbide precipitation at grain boundaries. In case any

sample shows evidence of carbide precipitation, the lot represented by the same may be

reheat treated, and resubmitted as a new lot at the discretion of the purchaser.

Otherwise the lot shall be rejected.

12.16 Permanent sat test on spring washers:

12.16.1 The spring washers under test shall be compressed flat for 3 Min. duration and released

between two plates having a hardness of 60 HRC, Min on release if the pressure, the

free height (h2 = 2S indicated in IS:3063 1994) of the washer shall not be less then that

given in table 2A &2B of IS:3063-1994. This compression and removal of pressure

shall then be repeated 20 times in quick succession after which the free height shall not

have further reduced.

12.17 Twist test on spring washers :

12.17.1 A portion of the washer shall be gripped in vice jaws and then equal portion shall be

gripped in wrench jaws as shown in Fig. 1 of IS:3063-1994..Edges of the wrench jaws

shall be sharp and parallel to vice jaws. The wrench shall than be rotated in a direction

that increases the free height of the spring washer till the washer is twisted through on

angle of 900. The washer shall show no sign of fracture.

13. MARKING AND MODE OF DELIVERY

13.1 The bolts shall be delivered assembled with their nuts and lock nuts and washers

(wherever required). The nuts and lock nuts shall be fully screwed on by hand.

13.2 Bolts, screws and nuts shall be provided with identification marking as laid down in IS:

1367 (Part.18)-1996.. The marking of the manufacturers trade mark of name is

mandatory for all products covered by the obligatory marking requirements for property

classes.

13.3 The fasteners shall be packed as described in IS:9141-1979.

13.4 Each package shall contain only one grade and dimension of fasteners.

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13.5 The packages shall be marked clearly and legibly with the following information.

a) The product designation;

b) A pictorial representation of the product, where possible;

c) Total number of pieces in the package;

d) Net and gross mass of package;

e) Name or identification symbol of the manufacturer;

f) Purchase order No. and consignee.

g) Date of inspection and inspecting authority.

h) Any other information as required by purchaser.

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