Microstructure and Wear Resistance of Laser-clad 316L+Ni60A Graded Coating on the Q345B Steel Surface
To improve the surface hardness and wear resistance of Q345B steel,three kinds of alloy coatings,namely,the 316L coating,the 316L+Ni60A composite coating and the 316L+Ni60A graded coating,were prepared by laser cladding.The microstructure and mechanical properties of the graded coatings were analyzed by OM,SEM,XRD and microhardness testing.In addition,the effects of the Ni60A alloy powder on the microstructure,hardness and wear resistance of the graded coatings were analyzed.The results show that there are no cracks and pores at the cladding layer or at the interface of the graded coating.The bottom of the cladding layer forms a columnar crystal structure.Meanwhile,the grain structure along the junction of the cladding layer changes from cytosolic dendrites to dendrites and then to fine equiaxed grains.The cladding layer surface has the highest hardness value,and the average hardness is greater than 580 HV.With the increase in the depth of the coating,the hardness gradually decreases and then drops sharply in the vicinity of the bonding zone between the cladding and the substrate.For the same wear conditions,the graded coating has the best wear resistance and shows a stable wear process.The friction coefficient of the graded coating has the minimum value of approximately 0.38,corresponding to a 54%reduction compared to the value of the substrate.At the ambient temperature,the wear mechanism of the 316L coating is mainly brittle peeling and plowing,the wear mechanism of the 316L+Ni60A composite coating is mainly adhesive wear,and the wear mechanism of the 316L+Ni60A graded coating is mainly plowing.Cr-Ni-Fe-C and Cr2Ni3 solid solutions are mainly responsible for the strengthening of the phases of the graded coating,and these solid solutions increase the hardness and wear resistance of the coating samples.
Laser cladding Graded coating Grain structure Wear morphology Solid solution strengthening
Wang Kai Zhu Jialei Feng Cong Li Wei Ma Guidian
Institute of Energy Engineering Intelligent Equipment Technology,Beijing Institute of Petrochemical Longyuan AFS Co.,Ltd.,No.7 Yudong Road,B District,Tianzhu Airport Industrial Zone,Shunyi District,Be
国际会议
北京
英文
454-461
2018-09-16（万方平台首次上网日期，不代表论文的发表时间）