Induction Hardening Company

We provide Annealing service, which is carried out during the designing process of tools, dies, crank shafts, gears, bushings, housings, medium sized nut, bolt, gears and pivots. It is done in a controlled atmosphere by using methanol.

Annealing is a method that is executed to recover cold work and relax stresses within a metal. When an annealed part is allowed to cool in the furnace, it is called a "full anneal" heat treatment.

Full annealing is the process of slowly raising the temperature about 50 ºC (90 ºF) above the Austenitic temperature line A 3 or line A CM in the case of Hypoeutectoid steels (steels with < 0.77% Carbon) and 50 ºC (90 ºF) into the Austenite-Cementite region in the case of Hypereutectoid steels (steels with > 0.77% Carbon).

It is held at this temperature for sufficient time for all the material to transform into Austenite or Austenite-Cementite as the case may be. It is then slowly cooled at the rate of about 20 ºC/hr (36 ºF/hr) in a furnace to about 50 ºC (90 ºF) into the Ferrite-Cementite range. At this point, it can be cooled in room temperature air with natural convection.

The grain structure has coarse Pearlite with ferrite or Cementite (depending on whether hypo or hyper eutectoid). The steel becomes soft and ductile.

We are a reputed organization, engaged in providing Hardening Services. The hardening process is mainly carried out for designing small components like screw drivers, small nut bolt, sirclips, small bushes, pins and rivets. In this process, we make use of advanced machines like hardening Two Mesh Belt Furnaces (Oil Quench, Water Quench) and Shaker Hearth Furnace.

Hardness is a process of carbon content of the steel, in which the hardening of steel requires a change in structure from the body-centered cubic structure found at room temperature to the face-centered cubic structure found in the Austenitic region.

The steel is heated to Austenitic region. When suddenly quenched, the Martensite is formed which is a very strong and brittle structure.

When slowly quenched it would form Austenite and Pearlite which is a partly hard and partly soft structure. When the cooling rate is extremely slow then it would be mostly Pearlite that is extremely soft.
 
'Hardenability' is achieving full hardness in material. The alloys, which have same amount of carbon content, achieve the similar amount of maximum hardness. Hence, the depth of full harness will vary with the different alloys.

We offer normalizing heat treatment service to different industries such as Mechanical, Civil Construction and Automobile. Normalizing heat treatment is mainly applied to achieve higher hardness and strength. In this process, the temperature is raised over 60 º C (108 ºF), above line A 3 or line A CM fully into the Austenite range.  Under this temperature, the structure is converted into Austenite and removed from the furnace then it is cooled under natural convection at controlled room temperature. This results in a grain structure of fine Pearlite with excess of Ferrite or Cementite. The degree of softness of a material in this process is mainly depends upon the cooling condition.

Normalizing process is a cost effective in nature as compare to full annealing process as it does not add the cost of controlled furnace cooling.

Annealing process is quite a different to normalizing as in this process; the annealed parts are uniformly softened by exposing them into controlled furnace cooling ambiance. In the normalizing process, the cooling is non-uniform as a result non-uniform material is formed.

We offer heat treatment Tempering Services that is specifically used in the fabrication of hand tools, nuts and bolts. In this process, we use Mesh Belt Tempering Furnaces and Pit Type Tempering Furnaces. This process is used to maintain the uniformity, continuous heating and socking of the components.

Tempering is a process, which is subsequent to quench hardening. The quench-hardened parts are brittle and the brittleness occurs due to predominance of Martensite and removed by tempering. The desired condition of hardness, ductility, toughness, strength and structural stability can be achieved by tempering.

The prevalent Martensite is an unstable structure when heated, the Carbon atoms diffuse from Martensite to form a carbide precipitate and the concurrent formation of Ferrite and Cementite, which is the stable form.

Procedure of Tempering:

• Tempering is done immediately after quench hardening. When the steel cools to about 40 ºC (104 ºF) after quenching, it is ready to be tempered.
• The part is reheated to a temperature of 150 to 400 ºC (302 to 752 ºF).
• In this region a softer and tougher structure Troostite is formed.
• Alternatively, the steel can be heated to a temperature of 400 to 700 ºC (752 to 1292 ºF) that results in a softer structure known as Sorbite. This has less strength than Troostite but more ductility and toughness.

The heating for tempering is best done by immersing the parts in oil, for tempering upto 350 ºC (662 ºF) and then heating the oil with the parts to the appropriate temperature.

Heating in a bath also ensures that the entire part has the same temperature and will undergo the same tempering. For temperatures above 350 ºC (662 ºF) it is best to use a bath of nitrate salts. The salt baths can be heated upto 625 ºC (1157 ºF). Regardless of the bath, gradual heating is important to avoid cracking the steel. After reaching the desired temperature, the parts are held at that temperature for about 2 hours, then removed from the bath and cooled in still air.