One of the methods of heat treatment is hardening. With this operation, the stiffness and abrasion strength of the material increases. Chipping tools and tools that need to withstand abrasion loads are hardened by this method.
Standard performance of hardening heat treatment work
Using a heat treatment furnace and other equipment, complete hardening operations are performed according to the relevant standards and instructions.
What is heat treatment and how is it done?
In general, heating and cooling metals in the solid-state to achieve the desired mechanical properties is called heat treatment. Heat treatment is used in all industries of automotive, machine building, aerospace, foundry, molding, welding, powder metallurgy, and defense and military industries.
Heat treatment objectives:
In general, the intended purposes of heat treatment can be divided into three categories:
1- Increasing hardness and strength
2- Softening and ductility
3- Reversing and smoothing the structure of parts (elimination of changes made in construction or working conditions such as welding, rolling, machining, etc.)
The principles of this method are similar to flame hardening, in that only the surface of the piece is austenitized and then rapidly cooled.
In this method, the surface is heated by a conductor coil from which alternating current with high frequency (in the range of 2 to 50 kHz ) Passes are done.
The hardened thickness depends on the flow frequency. The higher the current frequency, the lower the current penetration depth and therefore the thickness of the hardened layer. In this method, the piece is placed near the current-carrying coil and after a few seconds reaches the austenitic temperature and immediately cools down quickly.
In this method, hardness of 60 HRC can be produced in some steels up to a depth of ٣ mm, and due to the short time that the part is exposed to high critical temperatures, oxidation, decarburization or grain growth is negligible.
The heating time by high frequency induction currents is very short and often about a few seconds. The figure shows how the gears are heated by the coil by induction.