42CrMo4钢风电主轴的热处理工艺

某公司生产的42CrMo4钢风电空心主轴产品某一型号出现淬火开裂的比例较高,报废率近20%。用ARL8860直读光谱仪、MTS万能试验机、SANS冲击试验机、徕卡光学显微镜等对该产品进行一系列理化检验,并结合相关理论基础分析发现,将原淬火工艺优化为860 ℃加热后预冷至820 ℃浸水淬火,淬火水冷20 min,极大降低了产品开裂风险,为该企业解决了技术难点。860 ℃保温,预冷至820 ℃,水淬保持20 min,后经610 ℃高温回火处理,得到回火索氏体+粒状贝氏体+贝氏体铁素体条块的复相组织,性能满足抗拉强度＞700 MPa,-30 ℃冲击吸收能量＞40 J的要求。

Heat treatment process of 42 CrMo4 steel wind power main shaft

A certain model of 42CrMo4 steel wind power hollow spindle products experienced high proportion of quenching cracking, and reached nearly 20% of rejection rate. So the heat treatment process for the products were optimized based on physical and chemical tests by using of ARL8860 direct reading spectrometer, MTS universal testing machine, SANS impact testing machine and Leica metallographic microscope, and combining with relevant theoretical basis. The experimental results show that the risk of product cracking can be greatly avoided by the optimized quenching process of heating at 860 ℃ and precooling to 820 ℃, then water cooling for 20 min which can solve the technique difficulty. The so-obtained multi-phase microstructure by quenching at 860 ℃, precooling to 820 ℃, then water cooling for 20 min and then tempering at 610 ℃ is composed of tempered sorbite+granular bainite+bainitic ferrite blocks, which can meet the performance requirements as R_m＞700 MPa, and KV₂(-30 ℃)＞40 J.