18CrNiMo7-6钢中小模数齿轮的渗碳淬火处理  

Carburizing and quenching treatment of 18CrNiMo7-6 steel gear with small and medium modulus

作　　者：李瑶 张伟[1] 李朝青 Li Yao;Zhang Wei;Li Chaoqing(Nanjing High Speed&Accurate Gear(Group)Co.,Ltd.,Nanjing Jiangsu 211100,China)

机构地区：[1]南京高精齿轮集团有限公司,江苏南京211100

出　　处：《金属热处理》2025年第2期260-263,共4页Heat Treatment of Metals

摘　　要：利用正交试验对18CrNiMo7-6钢中小模数齿轮进行不同工艺的渗碳淬火处理,并对热处理后的表面硬度、有效硬化层深度和组织进行分析。结果表明,强渗碳势1.10%条件下,扩散碳势为0.65%~0.85%时,淬火时间1.5 h,回火时间4 h,及淬火时间1.0、1.5 h,回火时间6 h,均可使18CrNiMo7-6钢齿轮表面硬度达到59 HRC以上,且有效硬化层深度及显微组织均满足技术要求。但组织观察发现扩散碳势0.85%、淬火时间1.5 h、回火时间4 h工艺下,碳化物及残留奥氏体均处于临界值,批量生产时有超标风险。综合考虑,确定18CrNiMo7-6钢齿轮渗碳淬火工艺为:强渗碳势1.10%、回火时间6 h,利用等值线匹配扩散碳势(0.65%~0.85%)与淬火时间(1.0~1.5 h)。Using orthogonal test,different processes of carburizing and quenching treatment were carried out on small and medium modulus gear made of 18CrNiMo7-6 steel,and the surface hardness,effective hardening layer depth,and microstructure after heat treatment were analyzed.The results show that the heat treatment processes with a strong carburizing potential of 1.10%and a diffusion carbon potential of 0.65%-0.85%,quenching time of 1.5 h and tempering time of 4 h,as well as quenching time of 1.0 or 1.5 h and tempering time of 6 h,can all achieve a surface hardness of over 59 HRC for the 18CrNiMo7-6 steel gear,and the effective hardening layer depth and microstructure meet the technical requirements.However,the microstructure observation finds that under the process of diffusion carbon potential of 0.85%,quenching time of 1.5 h,and tempering time of 4 h,both the carbides and retained austenite are at critical values,and there is a risk of exceeding the standard during mass production.After comprehensive consideration,the optimum carburizing and quenching process for the tested 18CrNiMo7-6 steel gear is determined as follows:strong carburizing potential of 1.10%,tempering time of 6 h,as well as diffusion carbon potential(0.65%-0.85%)matched with quenching time(1.0-1.5 h)by contour method.

关 键 词：18CrNiMo7-6钢 齿轮 渗碳淬火 硬度 组织 

分 类 号：TG162.7[金属学及工艺—热处理]