热处理对高速钢轧辊工作层硬度和组织的影响

Effect of Heat Treatment on Hardness and Microstructure of High SpeedSteel in Working Layer for the Centrifugal Casting Roll

为优化复合高速钢轧辊的热处理工艺和简化热处理装备,采用硬度测试和金相试验手段研究复合轧辊工作层高速钢在不同淬火温度、淬火方式以及回火工艺下的辊面硬度和显微组织演化规律。结果表明,1220℃水冷方式淬火+560℃两次回火工艺处理后高速钢辊面出现较弱的二次硬化效应,硬度沿辊面分布的波动大,多边形硬质相多;1250℃风冷、油冷方式淬火+650℃两次回火工艺处理后辊面出现较强的二次硬化效应,硬度沿辊面分布均匀,硬质相球化率高;最终确定1250℃保温120 min风冷方式淬火+650℃保温120 min两次回火作为现场复合轧辊的生产工艺。

In order to optimize the heat treatment process of the composite high-speed steel roll and simplify the heat treatment equipment,the evolution of composite roll work layer high-speed steel’s hardness and microstructure after heat treatment of quenching and tempering at different temperature and different quenching method were studied by means of optical microscope(OM)and Rockwell hardness test.The results showed that the high-speed steel roll surface has a weak secondary hardening effect after quenching at 1220℃by water cooling+560℃twice tempering process,the hardness distribution along the roll surface has large fluctuations,and there are many polygonal hard phases.The high-speed steel roll surface has a strong secondary hardening effect after quenching at 1250℃by wind and oil cooling+650℃twice tempering process,the hardness is evenly distributed along the roller surface,and the spheroidization rate of the hard phase is high.Finally,the field producing process composite high-speed steel rolls is heated at 1250℃for 120 min and wind quenched then two tempered at 650℃for 120 min.