Heat treating a steel part of a car, comprises performing isothermal treatment for bainite formation, where the isothermal treatment is carried out by a controlled induction heating, direct induction, and low frequency induction

摘要

The method comprises performing isothermal treatment for bainite formation, where the isothermal treatment is carried out by a controlled induction heating, direct induction, and low frequency induction. The step of isothermal treatment is carried out at a temperature of 300-500[deg] C for a limited duration according to a diagram in a time interval between a moment of beginning of bainite formation and a moment of end of bainite formation. The method further includes: heating a steel part; hardening the part at a favorable temperature with the bainite formation; and cooling the part. The method comprises performing isothermal treatment for bainite formation, where the isothermal treatment is carried out by a controlled induction heating, direct induction, and low frequency induction and in a tunnel kiln heated by induction. The step of isothermal treatment is carried out at a temperature of 300-500[deg] C for a limited duration according to a diagram in a time interval between a moment of beginning of bainite formation and a moment of end of bainite formation. The method further includes: heating a steel part; hardening the part at a favorable temperature with the bainite formation, where the hardening step is followed by the isothermal treatment; and cooling the part. The heating step is carried out by induction and in an oven. The step of hardening is carried out for lower than 20 seconds. The step of cooling is carried out in liquid or gas phase by blowing.