机车齿轮常用渗碳钢的淬火畸变控制

Quenching distortion control of conventional carburized steel for locomotive gear

对20Cr2Ni4、20CrNi2Mo、18CrNiMo7-6 3种渗碳钢成分及淬透性进行了测试及试验比较,随后对这3种渗碳钢制作的大型盘齿轮从原材料、设计、锻造预备热处理、去应力退火、渗碳工艺等进行了优化控制,对不同材料的重载齿轮渗碳淬火前后尺寸精度进行了检测对比分析。结果表明:3种渗碳钢淬透性均较高,从高到低顺序为20Cr2Ni4、18CrNiMo7-6、20CrNi2Mo; 3种渗碳钢制造的重载齿轮渗碳淬火后最大变形量为0.182～0.219 mm,齿轮热处理后精度等级为10～11级;试验结果说明了3种渗碳钢制作的不同材料的同一结构尺寸的大型重载盘齿轮渗碳淬火畸变区别不大,齿轮畸变控制均取得了理想的效果。

The composition and hardenability of three kinds of carburized steels(20Cr2Ni4,20CrNi2Mo and 18CrNiMo7-6)were measured and comparatively tested,and the large-sized disc gears respectively made of these three kinds of carburized steel were optimized in terms of raw materials,design,pre-heat treatment for forging,stress removal annealing,carburizing process,etc.A comparative analysis of dimensional accuracy was implemented before and after carburizing and quenching of heavy duty gears made of different materials.The results show that the hardenability of the three materials is listed in a from-high-to-low order as 20Cr2Ni4,18CrNiMo7-6 and 20CrNi2Mo,corresponding to a maximum deformation of 0.182-0.219 mm after carburizing and hardening process and an accuracy of Grade 10-11 after heat treatment,which indicates that the overall deformation differences of the heavy duty gears made of the three kinds of steels after carburzing and quenching is not so obvious,and the satisfactory deformation control is obtained.The overall deformation differences of the heavy duty gears made of the three kinds of steels after carburzing and quenching is not so obvious,and the satisfactory results are obtained.