Research on the Microstructure and Properties of Stellite6/WC Composite Coatings via Laser Cladding

• Published in: JOM (1989) Vol. 76; no. 7; pp. 3769 - 3782
• Main Authors: Yang, Jianjun, Peng, Hai, Zhao, Kangwei, Fan, Caihe, Luo, Deng, Wu, Qin, Ou, Ling, Yin, Shiyang, Dong, Shiyun, Wang, Qiangping, Zhang, Zaiyu
• Format: Journal Article
• Language: English
• Published: New York Springer Nature B.V 01.07.2024
• Subjects: Corrosion potential; Corrosion resistance; Corrosion resistant steels; Corrosive wear; Crystals; Dilution; High strength steel; High strength steels; High temperature; Investigations; Laser beam cladding; Lasers; Microhardness; Microstructure; Recrystallization; Service life; Shock absorbers; Shock resistance; Stainless steel; Substrates; Tungsten carbide; Wear resistance
• ISSN: 1047-4838
• DOI: 10.1007/sll837-024-06561-y

This study applied a stellite6/WC composite coating, renowned for its wear and corrosion resistance, onto Q960 high-strength steel through laser cladding technology. The study aimed to investigate the influence of varying WC content and cladding power on the microstructure and properties of the coating. Findings indicated that the microstructure of the stellite6/WC coating evolved from planar crystals at the bonding interface to dendritic and cellular crystals in the central region, ultimately resulting in equiaxed crystals at the top. Despite the increased WC content, the dilution rate of the composite coating remained approximately 15%. Under the combined influence of a high-energy laser and high-temperature molten pool, WC particles experienced fracture and recrystallization, resulting in phases such as WC, W2C, C03W3C, C04W2C, and Co-rich. For example, at WC content levels of 10 wt.%, 20 wt.%, and 30 wt.% in the 550 W cladding, the average microhardness values were 457 HV, 535 HV, and 1045 HV, respectively. Likewise, the average wear loss for the composite coating and substrate stood at 12.5 mg, 9.2 mg, 5.8 mg, and 30.2 mg, respectively. Additionally, the recrystallization of elements such as Co, Cr, and Ni markedly enhanced the corrosion resistance of the Q960 steel after cladding. At a cladding power of 550 W, the corrosion resistance of the composite coating is superior. However, an increase in WC content slightly diminishes the composite coating's corrosion resistance, with the 30 wt.% WC coating exhibiting a self-corrosion potential of - 732 mV. The study demonstrates that a stellite6/WC composite coating can substantially enhance the wear and corrosion resistance of a shock absorber piston rod, thereby extending the service life of the automobile shock absorber piston rod.