杜佳俊,米佳良,师陆冰,陈超,刘忠明,王文健,丁昊昊.18CrNiMo7-6齿轮钢表面激光熔覆及其胶合承载性能研究[J].表面技术,2023,52(9):420-429.
DU Jia-jun,MI Jia-liang,SHI Lu-bing,CHEN Chao,LIU Zhong-ming,WANG Wen-jian,DING Hao-hao.Laser Cladding of 18CrNiMo7-6 Gear Steel and Its Scuffing Load Capacity[J].Surface Technology,2023,52(9):420-429 |
| 18CrNiMo7-6齿轮钢表面激光熔覆及其胶合承载性能研究 |
| Laser Cladding of 18CrNiMo7-6 Gear Steel and Its Scuffing Load Capacity |
| 投稿时间：2022-07-08 修订日期：2023-02-28 |
| DOI：10.16490/j.cnki.issn.1001-3660.2023.09.038 |
| 中文关键词: 激光熔覆 18CrNiMo7-6齿轮材料 微观组织 胶合损伤 |
| 英文关键词:laser cladding 18CrNiMo7-6 gear material microstructure scuffing damage |
| 基金项目:三峡后续工作项目(SXHXGZ-SCJ-2020-1);中国博士后科学基金(2021M692951);四川省区域创新合作项目(2022YFQ0113);河南省高等学校重点科研项目计划(21A460009) |
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| Author | Institution |
| DU Jia-jun | Tangshan Research Institute, Southwest Jiaotong University, Hebei Tangshan 063000, China |
| MI Jia-liang | China Academy of Launch Vehicle Technology, Beijing 100076, China |
| SHI Lu-bing | Zhengzhou Research Institute of Mechanical Engineering Co., Ltd., Zhengzhou 450001, China;Tribology Research Institute, Southwest Jiaotong University, Chengdu 610031, China |
| CHEN Chao | Zhengzhou Research Institute of Mechanical Engineering Co., Ltd., Zhengzhou 450001, China |
| LIU Zhong-ming | Zhengzhou Research Institute of Mechanical Engineering Co., Ltd., Zhengzhou 450001, China |
| WANG Wen-jian | Tangshan Research Institute, Southwest Jiaotong University, Hebei Tangshan 063000, China;Tribology Research Institute, Southwest Jiaotong University, Chengdu 610031, China |
| DING Hao-hao | Tangshan Research Institute, Southwest Jiaotong University, Hebei Tangshan 063000, China;Tribology Research Institute, Southwest Jiaotong University, Chengdu 610031, China |
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| 中文摘要: |
| 目的 基于激光熔覆技术提高18CrNiMo7-6齿轮钢的胶合承载性能。方法 以不同比例的ZrO2、MoS2和Ni基合金粉末为熔覆材料，采用同轴送粉激光熔覆技术在18CrNiMo7-6齿轮材料表面制备2种激光熔覆合金层，分析熔覆层的微观组织与显微硬度，并利用MJP-30A滚动接触摩擦磨损试验机对激光熔覆试样和渗碳试样进行胶合承载性能模拟试验。结果 NiCr20-3%ZrO2(质量分数，下同)熔覆层主要由枝晶组织和胞晶组织组成，其表面硬度约为620HV0.5;NiCr20-3%ZrO2-1%MoS2熔覆层相组成物有胞状晶、树枝晶和黑色的花形状颗粒，其表面硬度约为486HV0.5;NiCr20-3%ZrO2和NiCr20-3%ZrO2-1%MoS2 2种熔覆试样的临界失效载荷较渗碳试样的分别提高了8.41%和44.86%;其中，渗碳试样为典型的热胶合损伤，临界闪温为207 ℃;NiCr20-3%ZrO2熔覆试样未达到胶合临界闪温条件，其失效机制为熔覆层材料的疲劳剥落;NiCr20- 3%ZrO2-1%MoS2熔覆试样在达到胶合临界闪温后，其表面的自润滑效果抑制了胶合的快速发展，当持续增大载荷至临界失效载荷后，随着表面疲劳裂纹的萌生与扩展最终形成局部材料脱落进而失效。 结论 与齿面渗碳强化相比，齿面NiCr20-3%ZrO2-1%MoS2激光熔覆强化更能有效提高胶合承载性能。 |
| 英文摘要: |
| As a typical failure of gear surface in high-speed and heavy-duty gear transmission system, scuffing is affected by the operating parameters, lubricating medium, material, surface roughness and surface hardness of the gears. Many manufacturing technologies have been widely used to improve the scuffing load capacity of gear. As a new surface strengthening and modification technology, laser cladding technology can effectively improve the wear resistance and scuffing load capacity of matrix materials, so it has a high application prospect for improving the scuffing load capacity of gear. The gear material selected in the test was 18CrNiMo7-6 gear steel. The cladding material was NiCr20 alloy powder with the addition of different contents of ZrO2 powder and MoS2 powder. The NiCr20 alloy powder and ZrO2 powder used were spherical particles with particle sizes of 100 μm and 50 μm respectively, while the MoS2 powder was lamellar particles with the size of about 10 μm. Before each laser cladding test, the cladding powders were mechanically mixed and dried, and the surface of the samples were subject to ultrasonic cleaning in the ethanol bath. Two kinds of laser cladding alloy coatings were prepared on the surface of 18CrNiMo7-6 gear material by coaxial laser cladding technology with ZrO2, MoS2 and NiCr20 alloy powders in different proportions. In the laser cladding, the laser power used was 500 W, the scanning speed was 2 mm/s, and the powder feeding rate was 11.1 g/min. After preparation, the microstructure and hardness profile of the coatings were observed. Scuffing tests for the laser cladding samples and carburized treated samples were carried out on the MJP-30 A rolling contact friction and wear testing machine. In the scuffing test, the load was increased step by step from 500 N according to the interval of 300 N. Each level of load acted for 3 minutes until the sample was scuffed, the sudden increase of friction coefficient was taken as the scuffing failure index. In the test, the rotating speeds of the upper and lower samples were set at 500 r/min and 200 r/min respectively, and the lubricating oil flow was 0.5 L/min. After the test, the damage of the samples were observed by optical microscope. The results indicated that the carburized gear sample was mainly composed of lath martensite and retained austenite and its surface hardness reached around 572HV0.5; the NiCr20-3%ZrO2 (mass fraction, the same below) coating was mainly composed of dendritic and cellular phases and its hardness reached around 620HV0.5; the NiCr20-3%ZrO2-1%MoS2 coating was composed of dendritic phases, cellular phases and black flower shaped particles and the hardness reached around 486HV0.5. The friction coefficient of the NiCr20-3%ZrO2 cladding sample and the NiCr20-3%ZrO2-1%MoS2 cladding sample was lower than that of the carburized gear sample. Compared with the carburized gear sample, the scuffing loads of the two cladding samples were increased by 8.41% and 44.86%, respectively. The carburized gear sample presented typical thermal scuffing damage features, and the critical flash temperature was calculated to be 207 ℃. This critical flash temperature was not reached in the failure of NiCr20-3%ZrO2 cladding sample and it presented a fatigue spalling damage of the cladding layer. The self-lubricating effect of the NiCr20-3%ZrO2-1%MoS2 cladding sample inhibited the rapid development of the scuffing damage after reaching the critical flash temperature. The failure was finally caused by the surface spalling with the initiation and expansion of surface fatigue cracks when the load was continued to increase to the critical failure load. Compared with carburization strengthening of gear surface, NiCr20-3%ZrO2-1%MoS2 laser cladding strengthening can effectively improve the scuffing load capacity. |
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