8Cr4MoV低合金锻钢超深淬硬层冷轧工作辊研制与应用

Trial-Manufacture and Application on Cold Work Roll With Super-Deep Hardening Layer of Low Alloyed Forged Steel 8Cr4MoV

采用50 kg真空感应电炉冶炼质量分数为4%Cr、0.8%C及少量N、Re的8Cr4MoV低合金冷轧工作辊试验钢,经过锻造、预备热处理试验后,检验试验钢的力学性能、微观组织,选择综合性能较好的钢种开展最终热处理试验,确定淬火工艺,然后利用选定的钢种和工艺试制武钢冷轧厂冷连轧机φ610 mm×1 700 mm超深淬硬层冷轧工作辊。试制工作辊毛坯采用电炉+真空脱气+电渣重熔工艺冶炼,夹杂物和有害气体含量低,辊身采用50/250 Hz双频感应加热淬火,虽然未采用深冷处理,其金相组织、硬度和超声波探伤结果较好,尤其残余奥氏体含量较低,符合试制工作辊技术要求。试用效果表明其耐磨性较高,使用寿命达到Cr2常规工作辊的1.6倍,淬硬层深度与Cr5超深淬硬层冷轧工作辊相当,且没有发生剥落,具有较好的抗事故性。

8Cr4MoV low alloyed cold work roll steels were smelted by 50kg vacuum induction furnace, containing about 4%Cr, 0.8%C, and appending a little of N and Re in it individually or together. After forged, quenched and tempered, the steels＇ mechanical properties and microstructures were examined and compared each other. The better was put into final heat-treatment test to determine the quenching temperature, and then to trial-manufacturing su- per-deep hardening layer cold work rolls of 1 700 mm body length for 4 H tandem cold mill in Cold Strip Mills WIS- CO. Through the process of EAR＋LF＋VD＋ESR, the trial steels were made with low content of inclusions and harmful gases. The body was quenched by 50/250 Hz induction hardening equipment without liquid nitrogen treatment. The trial-roll microstructure, hardness and ultrasonic inspection were very good, especially the amount of residual austenite under control. The trial-roll performances show that their wear-resistance is higher, service life is longer about 1.6times of Cr2 conventional cold work roll, the hardening layer depth is deeper corresponding to Cr5 super-deep hardening layer cold work roll, and no spalling, accident-resistance is better.