Determination of Quenching Heating Temperature of Steels During Rapid Heat Treat
Posted by BalunShu on March 23rd, 2019
The quenching heat treatment of steel consists of two parts: heating and cooling, of which quenching heating involves two important parameters, the quenching temperature and quenching heat preservation time. The selection and determination of these two parameters is an important condition to finish the quenching heating target. Quenching heating is to heat the steel above the critical point, and preserve the heat at a suitable temperature so that it completely converts to austenite and the alloy compounds and carbides are fully dissolved and evenly distributed in austenite. Under the condition of rapid thermal treatment of induction heating, in order to finish the purpose of quenching heating, the first condition is to determine the quenching heating temperature according to the following factors.
1. The impact of rapid heating on the critical point of steel: The critical point of Steel, Ac1 and AC3, changes with heating speed increasing. The change range depends on the chemical composition of steel. Under normal circumstances, Ac1 and Ac3 increase with the increase of heating speed. Therefore, the quenching heating temperature must be based on the chemical composition of steel and induction heating speed. We can not use the traditional heat treatment of quenching heating temperature, and we need to use higher quenching heating temperature to ensure a complete austenite of steel.
2. The impact of rapid heating on the dissolution of the alloy elements and their compounds: When quenching and heating, the alloy elements in steel and the forming compounds and carbides can be incorporated into the austenite to form solid solution, so that the steel can be strengthened after the later heat treatment. Induction heating quenching has a short holding time when heated, which is unfavorable for the dissolution of alloy elements and their compounds. Thus, only by improving the temperature measures can we promote its dissolution.
3. The impact of rapid heating on austenite homogenization: Quenching temperature is an important condition for homogenization of carbon distribution in austenite. The austenite uniformity is directly related to the structural characteristics of quenched structure and the microstructure and properties of steel after tempering. Therefore, quenching temperature should meet the requirement of austenite homogenization.
To sum up, the above requirements should be taken into account when determining the quenching heating temperature under rapid heating conditions. At the same time, we must consider the short time of rapid heating and quenching time to decide the quenching heating temperature.
Lihua Machinery and Equipment Co., Ltd. in Dongguan City specializes in the production of induction heating power supply equipment. The company's products are widely used in metal processing, hardware plastics, household appliances, sanitary ware, refrigeration, automobile, weapon industry and other heat source equipment industry, using technics such as heat forming, welding, quenching, melting, annealing, heat coordination etc.
