Heat Treatment Salts

Till today, in the field of Heat Treatment lot of changed have taken place but the indian industrial sector has not been aware of these changes and as such they have been continuimg the same technology that was being used 10 to 15 years ago.

So, Dhatukarm took it seriously and therefore decided to make available the latest heat treatment technology which is quite informative, economical and best result oriented. 

Salt Bath Heat-Treatment

Molten salts are usually used as a medium in carburising,Hardeing,Annealing,Pre-heating,Tempering,Martempering,Austempering ect. Molten salt bath of various composition are available to cover the temperature range of  150oC -1350oC.

We offer heat treatment salt to our esteemed clients. These heat treatment salt are available in various forms to meet the requirement of heat treatment applications of varied industries like automotive, fasteners and medical equipment. Our range is known for precise pH value, accurate composition and effectiveness.

Our products cover the entire range of chemicals used in the salt bath heat treatment process.

  •   The Molten Salt Bath method offers many advantages over alternative processes of heat treatment.
  •   Parts treated in salt baths have a clear bright scale–free finish.
  •   Decarburization can be completely eliminated in salt baths.
  •   The circulation of molten salt provides uniform temperature throughout the charge giving accurate temperature control and uniform results.
  •   The rapid rate of heat transfer by salt enables a high output to be obtained from a relatively low investment and costs.


Chemicals Specification
Tempering Salt  • H.Q.-150
 • H.Q.-220
 • H.Q.-540
Neutral Salt     • H.Q.-660  • H.Q.-970  
Carburising Salt    • Case-carb (used with sodium cyanide)
Economizer  • Graphite Flakes

Cyaniding Salt

LCN-870 :- Salt is used for liquid carburizing. It produces a file hard wear resistance surface on ferrous parts. When steel is heated above Ac1, the surface of the steel absorbs both carbon and nitrogen from the molten bath. Salt gives cases less in carbon and more in nitrogen than in case of liquid carburizing. Operating Temperature - 760oC – 870oC. Aging Time - 4 to 8 Hours at 700oC (During Aging No Economizer is used.)

Case Carburizing Salt

SURFACE CARB-H : It is a cyanide salt with activators. It is extensively used for automobile components of mild and alloy steel gears of tractors, lathes and textile Machinery components. This bath is usually prepared by adding 2 parts of TF-11A and 1 part of Surface Carb-H. by weight.Only SURFACE CARB-H is added to maintain the bath at a working strength.

Operating Temperature - 845.oC – 925oC

SURFACE CARB-S : This bath is made exactly as Surface Carb-H bath i.e by adding 2 parts of TF-11A and 1 part of Surface Carb-H. by weight.The cyanide content of the melt is maintained at 12% NaCN. Only SURFACE CARB-S is needed to regenerate the bath.
Alloy case hardening steel parts treatment work is directly quenched in Tempering salt (H.Q.–150) after carburizing.
Operating Temperature - 900oC – 950oC

H.Q Carb Activator or TF-11A : It is used to increase the bath level when the bath level is too low and only addition of Surface-Carb H and Surface Carb-S increases the cyanide percentage to much higher strength which is not desirable. It is also used for carburizing with pure cyanide.
TF-11A is also used for less time and more case depth.



Economizer is used to form a surface layer on the surface of baths. It form a top layer which reduces thermal losses due to radiation. It also reduces fuel consumption and increased pot life.

Three types of Economizer are available:

1. H.Q. Economizer Flake
2. H.Q. Economizer Powder
3. H.Q. Ash-Free Economizer Powder.


1. H.Q. – 660 :  H.Q.–660 is used with H.Q Regenerator powder in mild steel or heat resisting alloy pots in electrode type furnace fitted with heat resistant electrodes and ceramic linings. It is also used for hardening various tool steels and preferably carburized steel and for preheating high speed steels and hot work die steels before treatment in Neutral Salt-970.

  Working Range:-660oC – 900oC
(can be raised to 1000oC if covered with Economizer)
  2. H.Q. – 720 : H.Q. – 720 with regenerator salts are used for treatment of carbon and alloy steel or off carburized parts which have been selectively machined to remove the case from certain parts before hardening, H.Q.–720 in readily water soluble salt. The Neutral salt–720 is also used for austenitizing work prior to hardening by quenching into tempering salt–150 for (martempering or austempering) or in Quenching Oil.

Working Range:- 720oC – 900oC
( can be raised to 10000C if covered with Economizer)


1. H.Q. – 970 : H.Q.–970 is used for hardening of high speed steels by heating to the austenitizing temperature of the steel and hot working steels to the appropriate hardening temperature. Neutral salt work as Austenitizing salt for tool steels in Heat–treatment of steels.

After treatment in H.Q 970, the tools are quenched in H.Q. 540, H.Q. 495 or oil.Subsequently the tools are tempered using H.Q. 540 or H.Q. 495.

  Working Range :- 980oC -1350oC

 2. H.Q. – 971 : H.Q.–971 has been specially compounded for Heat-Treatment of Cobalt High speed steel which is prone to decarburisation. It is also used for hardening of high speed steels and hot working steels with minimum amount of decarburisation.

Working Range :- 980oC -1350oC


1. H.Q.–830 – Neutral Salt 830 is used for Hardening Chromium rust resistance steel which include steels used for cutlery. Neutral salt 830 is used for hardening tool steels containing 2% carbon, 12% chromium and many others Hot working steels.

  Working range :– 830oC – 1100oC
  5. H.Q.–1100 – Neutral salt 1100 is a decarburizing free salt especially when tools after hardening are not required to be ground on each side of the cutting edges of steel tools.

  Working Range:- 1000oC – 1300oC


1. H.Q.–540 : Tempering salt is chloride based quenching salt for quenching of tools in high speed steel, or Austenitized steel from neutral salt–970 bath in order to reduce the danger of cracking and distortion.

Working Range:- 540oC –700oC

 2. H.Q.–495 : Tempering Salt is chloride based Quenching Salt for quenching of High speed steels and H.Q. 495 is also used for hardening/Tempering in temperature range of 4950C - 7000C.

  QSR (Quenching Salt Reducer) : This is a specially formulated reducing or degassing salt used for lowering the temperature of quenching salt / tempering salt which are have raised due to quenching bath. This upsets the eutectic composition and increases melting point thereby causing freezing of the top layer of the molten salt.

  This imbalance can be corrected by periodic addition of Quenching Salt Reducer, to restore quench bath fluidity.


H.Q–650 :- H.Q.–650 is used for annealing low, medium and high carbon steel. It is used in metal pots in electrode type furnace.

  H.Q.–650 is used for gray Iron. Annealing of gray iron consists of heating it to a temperature up to 720oC / high enough to soften it, thus improving its machinability. As the temperature increases above 590oC. The rate at which iron-carbide decomposes to Ferrite–Graphite increases markedly, reaching a maximum at lower transformation temperature (760oC for unalloyed or low alloy iron)

  Working range: – 680oC – 760oC

Ferritizing anneal - 704oC – 760oC for 1 hour

Medium ("full") - 787oC - 898oC for 1 hour

Grahitizing anneal - 898oC – 954oC 15m –1 hour


1. H.Q.-150 :- H.Q.–150 is widely used for tempering and give uniform resluts at low cost.The salt is used as a quenching bath in martempering and as a quenching cum transformation bath in austempering of steel. H.Q.-150 are used for en 61, dies, tabs, punches, collets etc.

  Working range :- 150oc – 550oc.

2. H.Q.–220 – It is a tempering salt for alloy steels and high carbon steels. It is also used for austempering and martempering of steel. It is also used for producing temper colour and mottled finished.With caustic soda solution it produces an intense jet black colour on steel.It is used on pliers, chisel, screw-driver, stamps, spanner, hammer, milling cutters, knives, tongs etc.

  Working range :- 220oc – 550oc.

Product Used for Temperature range application
H.Q.-150 5210/en, dies, taps, puncher, collects. 150oc-550o; tempering salt suitable for martempering & austempering
H.Q.-220 pliers, chisel, screwdrivers, stamp, spanners, hammer, milling cutters, knives, tongs etc. 230oc-550o tempering salt for alloy steels and high carbon steels. martempering & austempering of steel.
H.Q.-540 empering salt for decarb free hardening of high speed steels 540oc-700o tempering & quenching for H.S. Steels, cutting tools after heating in. H.Q-970.
H.Q.-495 tempering salt for tool steels. 495oC-700o tempering & quenching for high speed cutting tools.


1. H.Q.–155 : H.Q.-155 is used in large chemical and petroleum industries as a heating or cooling medium in the molten state. It enables uniform temperature te be maintained throughout the equipment. It is used for heating moulds for producing mouldings of thermo-setting or for curing rubber.

Working Range:- 155oC –540oC


1. H.Q.–330 : H.Q.-155 is suitable for solution treatment of aluminium alloys at 480-535oC before quenching into water or for annealing the same alloys at 380-400oC after cold working and before further deformation.After the solution treatment, the parts are quenched in water and then hardened by heating in H.Q. 150 at 160-200oC.

Working Range:- 330oC –535oC