| 引用本文: | 宋靖东,何卫锋,罗思海,曹振阳,梁晓晴.激光冲击强化前处理对AISI9310齿轮钢低温渗碳的影响*[J].中国表面工程,2023,36(6):155~162 |
| SONG Jingdong,HE Weifeng,LUO Sihai,CAO Zhenyang,LIANG Xiaoqing.Effects of Laser Shock Peening on Low Temperature Carburizing of AISI9310 Gear Steel[J].China Surface Engineering,2023,36(6):155~162 |
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| 激光冲击强化前处理对AISI9310齿轮钢低温渗碳的影响* |
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宋靖东1,2, 何卫锋1,2,3, 罗思海3, 曹振阳1,2, 梁晓晴3
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1.西安交通大学航空动力系统与等离子体技术全国重点实验室 西安 710049;2.西安交通大学机械工程学院 西安 710049;3.空军工程大学航空动力系统与等离子体技术全国重点实验室 西安 710038
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| 摘要: |
| AISI 9310 钢是一种高强度渗碳齿轮钢，具有较好的韧性。服役过程中，齿面极易发生磨损和接触疲劳失效损伤。为有效改善 9310 齿轮钢的耐磨损和抗接触疲劳性能，实现磨损和接触疲劳性能协同强化，提出采用激光冲击（LSP）+渗碳（LC） 复合强化的技术思路，采用激光冲击强化技术对 AISI 9310 钢基体进行前处理，再对其开展低温渗碳热处理。为进一步研究 LSP 和 LC 对 9310 齿轮钢微观组织形貌的影响规律，利用光学显微镜、扫描电子显微镜和电子背散射衍射表征渗碳层微观组织形貌和截面方向的晶体学特征，并对试件截面方向的硬度进行考核。研究结果表明，AISI 9310 钢的渗碳层厚度约为 14 μm, 最大硬度约为 305.67 HV，硬化层厚度约 300 μm；LSP 前处理后，渗碳层厚度提升到 23 μm，最大硬度提升到 328.87HV，硬化层厚度提升到约 700 μm。对比发现，LSP 前处理分别可将 9310 钢低温渗碳层厚度提升 64.3%，渗碳层硬度提升 23.17 HV， 硬化层深度提升 133%。这主要是低温渗碳对 9310 钢的 Kernel 平均取向差（KAM）和小角度晶界影响较小，但是 LSP 前处理可引入塑性变形并提升小角度晶界比例，有助于碳元素扩散，促进 9310 钢低温渗碳行为，提升渗碳层厚度、硬化层硬度和厚度。初步解决了 LSP 前处理诱导微观组织缺陷促进碳元素扩散的问题，可为 LSP 复合强化提升航空齿轮关键部件服役寿命提供技术支撑。 |
| 关键词: 激光冲击强化 低温渗碳 AISI 9310 钢 小角度晶界 硬度 |
| DOI：10.11933/j.issn.1007-9289.20221231004 |
| 分类号:TG156；TB114 |
| 基金项目:国家重大科技专项（2017-VII-0003-0096）；国家自然科学基金（52005508）；中国科协青年人才托举工程（YESS20200321）资助项目 |
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| Effects of Laser Shock Peening on Low Temperature Carburizing of AISI9310 Gear Steel |
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SONG Jingdong1,2, HE Weifeng1,2,3, LUO Sihai3, CAO Zhenyang1,2, LIANG Xiaoqing3
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1.National Key Lab of Aerospace Power System and Plasma Technology, Xi’ an Jiaotong University,Xi’ an 710049 , China;2.School of Mechanical Engineering, Xi’ an Jiaotong University, Xi’ an 710049 , China;3.National Key Lab of Aerospace Power System and Plasma Technology, Air Force Engineering University,Xi’ an 710038 , China
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| Abstract: |
| AISI 9310 steel is a kind of high-strength carburized steel with good toughness. Owing to its material properties, this steel is usually used to fabricate gear parts. Gear tooth surface is prone to wear and contact fatigue damage during service processing. Therefore, to effectively resolve the resistance properties and for the synergistic strengthening of the wear and contact fatigue properties, the AISI 9310 steel sample was processed by laser shock peening (LSP) and then treated by low temperature gaseous carburization (LC). The carburized layer and cross-sectional crystallographic characteristics were imaged using optical microscopy (OM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD); subsequently, the cross-sectional hardness was measured. The following results were obtained. After LC treatment, a white carburized layer, which was approximately 14-μm thick and uneven, was induced on the 9310 steel matrix surface. The maximum hardness achieved for the carburized layer of 9310 steel was about 305.67 HV with the depth of work hardening being 300 μm. The maximum hardness of the LCed sample was enhanced by 27.56% compared to the as-received sample. However, with pre-LSP treatment, the thickness of the carburized layer of 9310 steel was improved to approximately 23 μm and the maximum hardness to approximately 328.87 HV with the depth of work hardening being 700 μm. The maximum hardness of the LSP-LCed sample was enhanced by 5.46 % compared to the LCed sample. However, in comparison, the pre-LSP treatment improves the thickness of the carburized layer by 64.3%, the maximum hardness by 23.17 HV, and the depth of work hardening by 133%. The underlying reasons for these enhancements are as follows. Generally, LSP treatment induces plastic deformation and improves the proportion of low angle grain boundary (LGB); this enhances the diffusion behavior of the carbon atoms, and consequently improves the hardness of the LCed layer and the depth of work hardening. After pre-LSP treatment, the carbon diffusion behavior and hardness of LC were enhanced. Specifically, combining pre-LSP and LC processing results in cross-sectional work hardening because LC alone can hardly influence the Kernel average misorientation (KAM) and proportion of LGB of as-received 9310 steel. In other words, pre-LSP improves the KAM of the LCed sample by 15.38% (from 0.52° to 0.60°), and the depth from 0-100 μm. Moreover, pre-LSP enhances the KAM of the LCed sample by 15.79 % (to 0.66°) and the depth from 100-200 μm. Finally, the low angle grain boundary was measured. Notably, LC does not affect the proportion of the low angle grain boundary and the cross-sectional distribution for 9310 steel. On the contrary, pre-LSP processing evidently enhances the proportion of the low angle grain boundary. At the depth of 0-100 μm, pre-LSP enhances the total proportion of the LGB of the LCed sample by 13.04% (from 36.8% to 41.6%). Moreover, the total proportions of the LGB of the LCed sample were enhanced from 36.8% to 55.8% and from 38% to 46.2% for the depth ranging from 100-200 μm and 200-300 μm, respectively. Based on the above results, the main conclusions to enhance the carbon atoms diffusion behavior are as follows. Pre-LSP enhances the carbon diffusion behavior of LC by inducing plastic deformation via increased KAM and increasing the proportion of low-angle grain boundary. Consequently, the easier carbon diffusion behavior of LC could induce the thicker carburized layer, the harder work hardening level, and even improves the thickness of work hardening layer. The problem of carbon diffusion enhanced by microstructure defects induced by LSP pretreatment is preliminarily solved. This resolution would provide technical support for LSP compound strengthening to extend the service life of key components of aviation gear. |
| Key words: laser shock peening low temperature gaseous carburization AISI 9310 steel low angle grain boundary hardness |
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