表面技术2024，Vol.53Issue(5)：96-107,12.DOI:10.16490/j.cnki.issn.1001-3660.2024.05.010
42CrMo钢表面激光熔覆钴基金刚石耐磨层组织及性能
Microstructure and Properties of Laser Cladding Co-based Diamond Wear Resistant Layer on 42CrMo Steel Surface
摘要
Abstract
The work aims to enhance the wear resistance of 42CrMo steel and improve the serious wear failure of 42CrMo steel.The cladding layer with material of diamond/WC particles reinforced Co-based composites was produced on the 42CrMo steel surface by a laser synchronous powder feeding machine.The laser power was 700 W during the cladding process,the powder feeding rate was 21 g/min,the scanning speed of the spot was 180 mm/min,the carrier gas flow rate was 4 L/min,the distance between the substrate and the laser cladding head was 13 mm,and the overlap rate between the adjacent cladding passes was 30%.The polished cross section was corroded with 10%HNO3 alcohol solution to prepare metallographic samples.Macro morphology and microstructure of the cladding layer were observed by SEM and EDS.The phase composition was detected by XRD,the microhardness of the cladding layer was measured by microhardness tester and the friction and wear tests were carried out.The diamond particles pretreated by Ti/TiC powder could improve graphitization and ablation.An appropriate amount of ZrH2 powder could improve the ratio of the width of the cladding layer to its thickness,and promote the convection mass transfer in the molten pool.At the same time,the active element Zr could improve the wettability of diamond and the metal bond could hold the diamond particles strongly.The overlapping cladding layer performed a regular surface and the microstructure of the cladding layer was mainly composed of fine dendrites and dense network carbide eutectic.Rapid melting and freezing velocity at the bonding interface could make all elements diffuse and change in gradient,and generate planar crystals with appropriate dislocation and slip ability.Therefore,the bonding strength between the cladding layer and the substrate was enhanced.The thermal characteristics of laser cladding was contributed to obtain the W2C,ZrC,M6W6C,γ-(Co,Fe),CoZr2,(Ti,Zr)O2,TiCx,Co3Ti and other substances in the laser cladding,and the dispersion distribution of new carbide phase could significantly improve the microhardness of the cladding layer.The average microhardness(1 002HV0.2)of the cladding layer was 3 times that of the substrate due to the fine grain and dispersion strengthening.The average wear mass loss with a value of 1.6 mg was obtained in sliding the cladding layer,which was the 1/2 compared with that in sliding the substrate.The average friction coefficient of the cladding layer was evidently lower than that of the substrate,indicating that the wear resistance of the cladding layer increased.The friction and wear test of the cladding layer showed that abrasive wear became the dominant wear mechanism in sliding the cladding layer,the diamond particles in the cladding layer were passivated,contributing to bearing the friction load.However,the diamond particles located in the wear track on the cladding layer kept an integrity statue and few grains were falling out.The microstructure of the cladding layer is uniform and dense,the microhardness and the wear resistance are significantly improved,so it can be used for surface strengthening of 42CrMo steel.关键词
激光熔覆/复合熔覆层/显微组织/显微硬度/耐磨性Key words
laser cladding/composite cladding layer/microstructure/microhardness/wear resistance分类
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罗亮斌,梁国星,刘东刚,郝新辉,黄永贵,赵建..42CrMo钢表面激光熔覆钴基金刚石耐磨层组织及性能[J].表面技术,2024,53(5):96-107,12.基金项目
中央引导地方科技发展资金项目(YDZJSX2021B003) （YDZJSX2021B003）
国家自然科学基金资助项目(52105473) （52105473）
山西省基础研究计划项目(20210302124050,20210302124121) （20210302124050,20210302124121）
山西省创新平台基地建设专项(202104010911007) （202104010911007）
山西省高等学校科技创新项目(2021L086) Central Government Guided Local Development Foundation(YDZJSX2021B003) （2021L086）
National Nature Science Foundation of China(52105473) （52105473）
Shanxi Provincial Research Foundations for Basic Research(20210302124050,20210302124121) （20210302124050,20210302124121）
Special Project for the Construction of Shanxi Provincial Innovation Platform Base(202104010911007) （202104010911007）
Science and Technology Innovation Project of Colleges and Universities in Shanxi Province(2021L086) （2021L086）
