liquid nitriding

Liquid Nitriding

Our process is non-pollutive, sulphar accelerated at low temperature (570 + 100 C ).

It is an ideal process to improve the resistance of ferrous materials to wear, seizure, corrosion & fatigue. For a specified period of time of soaking of components in bath, produces a compound zone of 10-25 microns & nitrogen difusion layer of 0.2-0.6mm. It advantageously replaces shallow depth case hardening & carburising.

Applications

Camshafts, Bushes, Roker Shafts, Tappets, Shafts, Oil/Fuel & Water Feed Pumps, Gears, Spindles, Bearings, Cylinder Liners, Sprokets, Guides, Cages, Valves, Rocker Arms, Slides, Crankshafts, Valve Guides, Shafts,Flanges, Pins, Tools, Dies, Sheet Metal Parts, Machine Parts, Stainless Steel Components, Cast Iron Items, Transmission Parts and ANY FERROUS MATERIAL

Furnace Size

600 mm dia X 1200 mm Depth.

Oxidising

The oxidising process has been developed to further improve corrosion resistance of ferrous material previously liquid nitrited. The process is carried out at 425 + 250 C, provides a pleasing black colour. This process can replace hard chrome in number of applications. This process eliminates problems like peel off, hydrogen embrittlement & non uniform plating thickness.

Salt bath nitriding is a thermo chemical process in which nitrogen and carbon are diffused simultaneously into the surface of the material.

The high concentration of nitrogen chemically combines with iron and other nitride forming elements to produce an outer layer of epsilon iron nitride, which is thin, hard and ductile. This layer is also known as the compound zone, which has increased surface hardness to enhance anti-galling characteristics, and lowers the coefficient of friction. This compound zone also functions as a solid film lubricant by providing a non-metallic interface between mating surfaces. Nitrogen of lower concentration continues to diffuse below the compound zone and forms a solid solution with the base metal iron. This zone is referred to as the diffusion zone and is noted for its improvement in fatigue strength.

SALT BATH NITRIDING

INTRODUCTION

Liquid Nitriding process involves enrichment of the Steel surface basically with Nitrogen and very small amount of carbon at a specified temperature range, by diffusion from cyanide-free molten salt bath.

This thermo-chemical transformation of the Steel surface enhances wear resistance, fatigue strength and anti-galling properties with least distortion and improves corrosion resistance.

It works very effectively for surface property enhancements on titanium, aluminum and chromium bearing steels as well as low alloy steels and stainless steels .

ENHANCEMENT OF PROPERTIES

Liquid nitriding increases wear resistance properties from 200% to 1000% , depending upon composition of base metal and fatigue strength by 20% to 100%.

PROCESS AND TECHNICAL DETAILS

Salt bath nitriding is performed at 5600 - 5700 C following necessary heat-treatment for core properties and finish machining. It ensures dimensional stability of processed parts and core properties which remain unchanged, provided heat treatment temperatures were higher than the liquid nitriding temperature, i.e. 5600 - 5700 C.

In liquid nitriding bath, which contains nitrogenous salts, nitrogen is released in a controlled and uniform manner at the interface of the work piece. Nitrogen by diffusion chemically combines with nitride –forming elements like iron, aluminium, chromium and forms a tough ductile compound layer with high mechanical and chemical properties like hardness, wear resistance, anti-galling and resistance to corrosion.

Just adjacent and below the compound layer, another layer diffusion zone is formed. Diffusion zone consists of a solid solution of nitrogen in the base material. The diffusion zone contributes to substantial enhancement of fatigue strength. There is a simultaneous diffusion of carbon in a small amount which contributes to property enhancement combining with the base metal.

ADVANTAGES :

i) Liquid nitriding process is highly active, more efficient and time – saving compared to gas nitriding.

ii) After liquid salt bath nitriding the parts can be quenched in water, oil or cooled in air.

iii) The salt mixture is almost cyanide-free. So the waste / carry over require minimum treatment for toxic effect.

iv) The nitrided parts can be given a bright lustrous black finish by a supplementary operation.

v) The thermo-chemical transformation involves negligible dimension change / distortion

APPLICATION :

Liquid nitriding has unique advantages – improvement of surface properties like wear resistance, anti-galling and chemical property as corrosion- resistance. Process time & energy cost being low, the process is cost saving.

Considering these, the process has wide application in automobile and other industries. The process is widely used for surface hardening of gears, cam shaft, spindles , slides and guides engine valves, bushes , flanges , aluminium Extrusion dies, hydraulic components, high speed steel tools, mining machineries, husking machines , pump bodies and many others.

NITRIDING SALT CYANIDE FREE

HARDENING & QUENCHING & TEMPERING SALT

MASKING COMPOUND

NITRIDING SALT CYANIDE FREE

Sl. PRODUCT NAME TEMPERATURECHARACTERISTICS

1. Hard Temp CN4 560 0 – 570 0 C. A specially designed base salt for nitriding of carbon steels,

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(Code No: 33 – 407) high speed steels and other type of alloy steels. Hard Temp CN2 salt is required to regenerate the bath.

2. Hard Temp CN2 (Code No: 33 – 406)

- A regenerator salt used in Hard Temp CN4 bath.

3. Additive 408(Code No: 33 – 408)

- An additive used in nitriding baths.

4. Salt Black N 386(Code No: 33 – 386)

400 0 – 420 0 C. A chemical blackening process used after nitriding of ferrous metals and alloy steel components. It produces a pleasing black finish over thenitrided surfaces.

NITRIDING SALT

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Hardening Salt , Neutral and Quenching Salts, Tempering and Heat Transfer Salts

Hardening Salt


1. Hard Temp H 402(Code No: 33 – 402)

760 0 to 950 0 C A carburising salt containing sodium cyanide and suitable activating agent. The carburising salt is capable of carburising mild steel and alloy case hardening steel upto depth of 2.5 mm.

2. Hard Temp HS 403 (Code No: 33 – 403)

760 0 to 950 0 C An excellent carburising salt containing sodium cyanide and activating agents capable of producing sufficient case depth required for mild steel and alloy case hardening steels.

3. Hard Temp F 750 (Code No: 33 – 404)

750 0 to 850 0 C A low cyanide containing salt specially developed for hardening high carbon steel files and medium or low carbon steel rasps. Slight decarburisation on the surfaces of the files can be removed by hardening in Hard Temp F 750.

Neutral and Quenching Salts


1. Hard Temp 660 (Code No: 33 – 416)

660 0 to 900 0C (upto 1000 0C if covered

A neutral salt normally used with Hard Temp A 453 regenerator for hardening tool steel and selectively

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with Hard Temp E 452)

carburised steel. Also used for preparing initial melts of carburising salts Hard Temp H 402. The salt can be used for preheating hot die steels and high speed steels prior tohardening.

2. Hard Temp 720 (Code No: 33 – 417)

720 0 to 900 0 C (upto950 0C if covered with

Hard Temp E 452)

A water-soluble neutral hardening salt normally used with Hard Temp A 453 regenerator for hardening various tool steels and selectively carburised steels. Sometimes it is also used with 1 – 10% sodium cyanide as a scale free heat treatment medium.

3. Hard Temp 830 (Code No: 33 – 418)

830 0 to 1100 0 C The salt is used with Hard Temp A 453 regenerator for hardening chromium rust resisting steels B. S. En 36 A-D and B.S. En 57.

4. Hard Temp 970 (Code No: 33 – 419)

970 0 to 1350 0 C Used for heating high-speed steels and hot work steels to the appropriate hardening temperature without scaling or decarburisation.

5. Hard Temp 495 (Code No: 33 – 420)

495 0 to 700 0 C Used for quenching and secondary hardening of high-speed steels preferably where the temperature required is 500 0 to 540 0 C.

6. Hard Temp 540 (Code No: 33 – 421)

540 0 to 700 0 C Specially developed for quenching high speed steels and hot work tool steels after heating in Hard Temp 970. It is also used for secondary hardening of high-speed tool steels and for tempering.

7. Hard Temp F 666(Code No: 33 – 423)

- A neutral salt for use with Hard Temp F 750.

8. Hard Temp 667 (Code No: 33 – 424)

- A specially designed salt used with carburising salt Hard Temp HS403 during initial bath make-up or subsequent replenishments, if required.

Tempering and Heat Transfer Salts


1. Hard Temp 150 (Code No: 33 – 436)

160 0 to 550 0 C Used for tempering after hardening. The salt may also be used as a quenching cum transformation bath when austempering jobs heated in muffle furnaces or salt baths.

2. Hard Temp 220(Code No: 33 – 437)

230 0 to 550 0 C Used for tempering after hardening. The salt may also be used as a quenching cum transformation bath when austempering jobs heated in muffle furnaces or salt baths.

3. Hard Temp 155 (Code No: 33 – 438)

155 0 to 540 0 C A heat transfer salt for use in large chemical or oil cracking installation as a heating or cooling medium.


- A special heat treatment salt used for specific purpose.


160 0 to 550 0 C A special tempering salt used after hardening.

Miscellaneous Chemicals for Heat Treatment

Sl. PRODUCT NAMECHARACTERISTICS

1. Hard Temp R 451 (Code No: 33 – 451)

A rectifier to be used along with neutral salts to keep the baths in non-decarburising condition.

2. Hard Temp E 452 (Code No: 33 – 452)

Used to form a surface layer on carburising and certain neutral salt baths to prevent fumes, conserve bath strength, minimize fuel consumption and increase pot life.

3. Hard Temp A 453(Code No: 33 – 453)

A regenerator for use in neutral salt baths to keep the baths in non-decurburising condition.


A very stable masking compound to be applied over components in various heat treatment processes.


A very efficient chemical used for detoxification treatment of cyanide and cyanate.

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MASKING COMPOUND

INTRODUCTION

It is an anti-carburising compound used while masking selected areas of component where carbon penetration is not desired. It works very effectively for the surfaces of the components where masking compound is applied during process of carburising

METHOD OF APPLICATION

Masking compound which can be easily applied on the chosen areas by brushing, dipping or by spraying. Normally a uniform layer obtainable by single coat application. Two coats of this compound is recommended where case depth

for carburising is more. TYPES OF MASKING COMPOUND

A) Non Aqueous Masking Compound.

This is a quick drying masking compound which is very stable and also effective in preventing carbon penetration on selected surfaces.

B) Water Based Masking Compound

This is a stable and eco-friendly masking compound easily applicable for prevention of carbon penetration as required

ADVANTAGES


1) Simple in application by brushing, dipping or spraying.

2) Quick drying in a well ventilated area.

3) Stable and eco-friendly in use.

4) No risk of cracking on uniform coating during process of heat treatment

5) Very much cost effective.

Our Equivalent Products :

Sl. PRODUCT NAMECHARACTERISTICS

1. Maskchem – 369(Code No: 22 – 369)

It is a non-aqueous anti-carburising compound used for masking of selective areas of components during heat treatment process. It is only used for LPG process.

2. Maskchem – 371(Code No: 22 – 371)

It is a non-aqueous anti-carburising compound used for masking of selective areas of componentsduring heat treatment process. It is used both for LPG and Alcohol.

3. Maskchem – 377(Code No: 22 – 377)

A thinner used for Maskchem – 369 and Maskchem – 371 both.

4. Maskchem – 376(Code No: 22 – 376)

It is a water based anti-carburising compound used for masking of selective areas of components during carburising process.

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