Characteristics of annealing furnace heat treatment

Annealing furnace can change the microstructure of steel through heat treatment, so as to improve the properties of steel. Heat treatment can significantly improve the mechanical properties of steel and prolong the service life of machine parts. Proper heat treatment process can eliminate various defects caused by hot working processes such as casting, forging and welding, refine grains, eliminate segregation and reduce internal stress, so as to make the microstructure and properties of steel more uniform.

The chemical composition and structure of the uniform steel treated in the annealing furnace, refine the grain, adjust the hardness, eliminate the internal stress and work hardening, improve the machinability of the steel and prepare for the subsequent quenching. Common annealing operations in production include complete annealing, isothermal annealing, spheroidizing annealing, stress relief annealing, etc.

Complete annealing and isothermal annealing are used for castings, forgings and hot rolled sections of carbon and alloy steels with hypoeutectoid steel composition. Sometimes it is also used for welded structures. Spheroidizing annealing is mainly used for carbon steel and alloy steel with eutectoid or hypereutectoid composition. Stress relief annealing is mainly used to eliminate the residual internal stress of castings, forgings, weldments, cold stamping parts (or cold drawn parts) and machining.

In the structure, the heating chamber of the annealing furnace adopts stainless steel framework, and the heat insulation screen is multi-layer graphite felt, which has long service life and easy maintenance. Graphite tube heater is adopted, which is easy to install and maintain and has low failure rate. The air cooling system is composed of high-power and high-speed motor, large air volume and high-pressure impeller, volute and guide plate, copper tube copper strip heat exchanger and guide device, which can realize the high-speed circulation of air flow heat exchanger fan guide device workpiece heat exchanger, so as to make the workpiece get rapid and uniform cooling.