重载汽车20CrMnMo齿轮激光淬火热处理工艺

Heating Processing of Laser Quenching on 20CrMnMo Gears Used in Heavy-load Automobiles

为研究20CrMnMo齿轮经激光淬火后的硬度值和微观组织以及与其他热处理方式相比的差异,采用"渗碳淬火"和"渗碳后不同参数的激光淬火"等工艺方法处理了一批齿轮;测定其齿面硬度值并对数据进行Matlab软件分析;采用扫描电子显微镜(SEM)对典型试样进行显微组织观察;测定和分析部分试样的晶粒度。结果表明:"渗碳后激光淬火"齿面的硬度值最高可达61.4 HRC,比渗碳淬火齿轮高2.3 HRC左右;渗碳后激光淬火的高硬度值试样的微观组织为致密的针状马氏体与板条状马氏体的混合,晶粒度为9级左右,有熔融现象的试样微观组织为回火索氏体,且不同激光参数处理的试样其微观组织类型和尺寸差别较大。因此20CrMnMo齿轮可以通过渗碳后的激光淬火工艺获得较高的硬度值、较好的微观组织和晶粒度。

To research the hardness and microstructure of 20 CrMnMo gears that were treated by laser quenching,a batch of gears were treated by the process of＂carburizing and quenching＂,and＂laser quenching after carburizing with different parameters＂;the hardness of tooth surface was measured and the date was analyzed though Matlab software;the microstructure of typical samples were observed by scanning electron microscope（SEM）;the grain sizes of some samples were measured and analyzed.Results show that the highest hardness of tooth surface treated by＂laser quenching after carburizing＂can achieve 61.4 HRC,2.3 HRC around higher than the carburizing and quenching gear.The microstructure of some samples with high hardness is the mixture of pyknoticneedle-shapedmartensite and lath martensite,whose grain size is about 9,the microstructure of the sample that appears a phenomenon of fusion is tempered sorbite,and the types and sizes of microstructure for the samples treated by different laser processing parameters are quite different.20 CrMnMo gear can obtain higher hardness,better microstructure and grain size through the process of＂laser quenching after carburizing＂.