Thermal treatment technology of high-nitrogen stainless bearing steel

The invention discloses a thermal treatment technology of high-nitrogen stainless bearing steel, comprising the following steps of: primarily preheating at a temperature of 650+/-10 DEG C and preserving the temperature for 25-35 min; secondarily preheating at a temperature of 850+/-10 DEG C and preserving the temperature for 20-45 min; quenching at a temperature of 1060+/-10 DEG C and preserving the temperature for 50-60 min; cooling to the room temperature after the quenching and performing cold treatment in half an hour at a temperature of -196+/-5 DEG C for 2-3 h for twice; and warming to the room temperature after the cold treatment and performing tempering immediately at a temperature of 160+/-5 DEG C for 4-4.5 h for twice. The best thermal treatment technology of 40Crl5Mo2VN high-nitrogen stainless bearing steel of the invention, which is finally determined on the basis of numerous experiments, not only effectively controls the content of the remained austenite to guarantee the size stability problem of the 40Crl5Mo2VN steel workpiece, but also solves the deformation problem and crack problem of the thermal treatment.