20Cr2Ni4A钢制内环工艺改进

Process improvement of inner ring made of 20Cr2Ni4A steel

针对液力变矩器的20Cr2Ni4A钢制内环经渗碳淬火后圆盖板翘曲度过大导致无法满足机加工要求这一问题,采用有限元方法模拟了装炉方式和在圆盖板上下端增加机加余量对内环渗碳淬火过程的应力场和变形场的影响,并进行了试验验证。结果表明,装炉方式和增加机加工余量对内环渗碳淬火过程应力场和变形场的影响很大,采用4种装炉方式进行淬火后内环的最大变形量按从大到小依次为长轴竖放、短轴竖放、吊放、横放。采用吊放装炉能使Φ215 mm薄壁处平面翘曲变形有效减小至0.29 mm,横放装炉翘曲度能控制到0.21 mm。当圆盖板上端机加工余量增厚至11 mm时,翘曲度能控制到0.19 mm。综合生产效率和成本,宜选用横放装炉生产。

Aiming at the problem that the round cover plate made of 20Cr2Ni4A steel inner ring of hydraulic torque converter after carburizing and quenching was warped too much to meet the machining requirements,the finite element method was used to simulate the effect of furnace charging mode and adding machining allowance at the upper and lower ends of the round cover plate on stress field and deformation field during the carburizing and quenching process of the inner ring,and the experimental verification was carried out.The results show that the charging method and increasing the machining allowance have a great influence on the stress field and deformation field during the carburizing and quenching process of the inner ring.The maximum deformation amount in the order from large to small after quenching with 4 furnace charging methods is long axis vertical placement,short axis vertical placement,horizontal placement and hanging placement.Using the hanging placement can effectively reduce the warpage deformation of the plane at thin wall ofΦ215 mm to 0.29 mm,and the warpage of the horizontal furnace can be controlled to 0.21 mm.When the machining allowance at the top of the round cover plate is increased to 11 mm,the warpage can be controlled to 0.19 mm.In terms of overall production efficiency and cost,it is advisable to use horizontal placement for production.