低压渗碳工艺对超高强钢硬度与组织的影响  

Effect of low-pressure carburizing process on hardness and microstructure of ultra-high-strength steel

作　　者：辛昕 魏云轩 张宇宇 高一帆 曾西军 王振强 XIN Xin;WEI Yunxuan;ZHANG Yuyu;GAO Yifan;ZENG Xijun;WANG Zhenqiang(Harbin Dongan Aero Engine Co.,Ltd.,Harbin 150066,Heilongjiang,China;College of Materials Science and Chemical Engineering,Harbin Engineering University,Harbin 150001,Heilongjiang,China)

机构地区：[1]中国航发哈尔滨东安发动机有限公司,黑龙江哈尔滨150066 [2]哈尔滨工程大学材料科学与化学工程学院,黑龙江哈尔滨150001

出　　处：《钢铁研究学报》2025年第2期236-247,共12页Journal of Iron and Steel Research

基　　金：国家科技重大专项资助项目(J2019-VI-0019-0134)。

摘　　要：低压渗碳技术用于第三代超高强齿轮钢表面处理时会存在碳化物聚集、奥氏体软层、渗层质量与渗层厚度矛盾等工艺问题。研究了引入“二次渗碳”工艺对1900 MPa级航空用低压渗碳齿轮钢的渗层质量、硬度与显微组织的影响。利用SEM、XRD、EPMA、EBSD和TEM等方式对渗层至芯部组织进行了精细表征。结果表明,引入“二次渗碳”工艺后,渗层无网状碳化物,整体碳含量增加,渗层硬度提升约20 HV,相同深度位置的微米级块状或条状富Cr碳化物增多,且位于表层的碳化物类型由M_(23)C_(6)为主转变成M_(7)C_(3)为主,亚微米尺寸M_(6)C球形碳化物略微减少,亚微米M_(23)C_(6)、纳米MC及M_(6)C碳化物大量生成。同时渗碳外壳层变厚,过渡层变窄。此外,“二次渗碳”试样芯部的硬度略微降低,原因是位错密度降低所致。When low-pressure carburizing technology is applied to the third-generation ultra-high-strength gear steel,there still exist process problems such as carbide aggregation,austenitic soft layer,contradiction between carburized layer quality and thickness.This study investigates the effect of the introduction of the"double carburizing"process on the quality of the carburized layer,hardness and microstructure of 1900 MPa aerospace low-pressure carburized gear steel.SEM,XRD,EPMA,EBSD and TEM techniques were employed to precisely characterize the microstructure from carburized layer to core.The results show that after the introduction of the"double carburizing"process,no network distributed carbides existed,the overall carbon content of carburized layer increased,and the hardness of carburized layer increased by~20 HV.The micron-sized block or strip shaped Cr-rich carbides at the same depth position increased,and this type of carbides located in the surface layer was mainly transformed from M_(23)C_(6)to M_(7)C_(3).The submicron-sized spherical M_(6)C carbides slightly decreased in quantity,meanwhile substantial amounts of submicron-sized M_(23)C_(6)carbides,nanometer-scale MC and M6C carbides are generated.At the same time,the carburized shell layer thickens and the transitional layer narrows.In addition,the hardness of the core of the"double carburizing"specimen is slightly reduced due to the decrease in dislocation density.

关 键 词：超高强齿轮钢 低压渗碳 壳层 碳化物 过渡层 

分 类 号：TG142.1[一般工业技术—材料科学与工程]