Effect of Cladding Current on the Microstructure and Properties of Fe-based Hard Coatings with High Mo and V Contents
Author of the article:ZHANG Ding 1,2 , SONG Qinglei 3 , ZHANG Ping 1 , GUO Xiping 2 , LIU Xueqiang 3 , SHEN Chengjin 1
Author's Workplace:1. School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China: 2. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China; 3. Xuzhou BUT Construction Machinery Joint-Stock Co., Ltd., Xuzhou 221005, China
Key Words: plasma cladding; high Mo-V Fe-based hard coating; microstructure; wear resistance; cladding pattern
Abstract:
To improve the wear resistance of cutting edge plates on digging buckets, Fe-based hard coatings with high Mo and V contents were prepared on Q345B steel by plasma cladding technology. The effects of cladding current (120, 140, 160 A) on the structure of the coatings were analysed, and the hardness, wear resistance and impact resistance of the coatings were investigated. The results show that the cladding current has a significant influence on the microstructure and interface quality of the coatings. The coatings mainly consist of a martensitic matrix with distributed fine spherical VC particles, polygonal Mo 2 B and lamellar composite M 2 (B, C). Localized unfused zones are observed at the interface between the substrate and the coating prepared at 120 A. As the current increases, the size of the VC particles in the coatings increases, their distribution density decreases, and the size of Mo 2 B decreases or even disappears in the coating prepared at 160 A, while the size of M 2 (B, C) increases and the number increases. The average hardness of the coatings is approximately 920 HV 0.1 , which is more than twice that of NM400 steel, and the weight loss is only 1/20 of that of NM400 under the same abrasion conditions, showing better wear resistance. The coating specimens exhibit good impact resistance, and the coatings with parallel cladding patterns are superior to those with vertical cladding patterns.