A heat treatment process for metals and glass

Process: Reheat the quenched steel to a temperature below A1 for holding, and then cool (generally air cooling) to room temperature. Quenching, a heat treatment process for metals and glass. Annealing, normalizing, quenching, and tempering are the 'four fires' in the overall heat treatment. Isothermal annealing. 

If it is not eliminated in time, the workpiece will be deformed during processing and use, which will affect the accuracy of the workpiece. During the cooling process, the lamellar cementite in the pearlite becomes spherical, thereby reducing the hardness. It is used to eliminate the hardening phenomenon (increase in hardness and decrease in plasticity) of metal wire and sheet during cold drawing and cold rolling

 Overall heat treatment is a metal heat treatment process that heats the entire workpiece and then cools it at an appropriate speed to change its overall mechanical properties. This phenomenon is called the first type of temper brittleness.SKF Bearings ManufacturersCommonly used quenching methods include single-liquid quenching, two-liquid quenching, graded quenching, austempering, and partial quenching. 

Fully annealed Process: heating 30-50℃ above Ac3→heat preservation→cooling with furnace to below 500℃→air cooling at room temperature. It is very important to use stress relief annealing to eliminate internal stress generated during processing. Therefore, it is widely used in important structural parts of automobiles, tractors, machine tools, etc. 

The holding time depends on the situation, usually 2 to 4 hours. The main purpose of annealing is to make the internal structure of the metal reach or close to the equilibrium state, and prepare for subsequent processing and final heat treatment. Concept: The steel is heated and insulated and then slowly cooled to obtain a process close to the equilibrium structure.