预硬化型合金模具钢板P20LL回火工艺与组织

Analysis on Tempering Structure and Internal Crack of P20LL Pre-hardening Alloy Die Plate

为改善预硬化型模具钢板心部组织,提高钢板探伤合格率,采用不同回火工艺,对在热轧生产线上预硬化的厚度80 mm的合金模具钢P20LL钢板进行了回火试验研究。试验结果表明,采用580℃×（5~7.5）h的回火工艺可以使厚度80 mm的P20LL在线预硬化模具钢板获得较为理想的组织。

In order to improve microstructure in the center of steel plate and plate qualification rate at detection, different tempering processes were adopted for P20 LL pre-hardening alloy die plate with 80 mm thickness. Test showed the ideal tempering process for P20 LL plate with 80 mm thickness in online pre-hardening treatment was 580 ℃ ×（5~7.5）h.