Heat treatment method for large high-speed steel cold-rolled work roll

The invention discloses a heat treatment method for a large high-speed steel cold-rolled work roll, and belongs to the technical field of heat treatment. The heat treatment method comprises pretreatment, preheat treatment and finish heat treatment. The preheat treatment comprises integral low-temperature preheat and continuous induction heating preheat. During continuous induction heating preheat, the temperature of the roll when the roll gets out of an induction coil is required to be 600-750 DEG C, the roll continues to move upwards, air cooling is conducted for 15-35 min after the roll gets out of the induction coil, and finish heat treatment is conducted. The heat treatment method is different from a conventional continuous induction quenching manner, the roll body continuous induction preheat treatment step is added on the basis of conventional integral preheat, and the heat treatment success rate of the large high-speed steel roll can be greatly increased. Meanwhile, cold treatment is added after first-time tempering of the roll is conducted, a roll body has hardness of 90 HSD or more after finish heat treatment of the high-speed steel cold-rolled work roll is conducted, and the technology requirement of a cold-rolled steel plate can be completely met.