Effect of Post-Cladding Heat Treatment on Microstructure and Performance of a Laser Cladded 2Cr17Ni2 Steel Coating

• Published in: Journal of materials engineering and performance 2023-02, Vol.32 (4), p.1778-1789
• Main Authors: Guo, Weimin, Jia, Zengqing, Liu, Guoqiang, Ding, Ning, Liu, Long, Xu, Huixia, Xu, Na, He, Jianqun, Zaïri, Fahmi, Wang, Xiebin
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Engineering Design; Materials Science; Physics; Quality Control; Reliability; Safety and Risk; Technical Article; Tribology
• ISSN: 1059-9495; 1544-1024
• DOI: 10.1007/s11665-022-07207-3

This work addresses the effect of post-cladding heat treatment (PCHT) on microstructure, micro-hardness and corrosion resistance of a 2Cr17Ni2 steel coating fabricated by laser cladding (LC). PCHT is carried out by heating the coatings to 650 °C and 1050 °C, respectively, holding for 1 h and cooling in air. Coatings before and after PCHT show much higher hardness and better corrosion resistance than substrate. 1050 °C treated coating shows hardness (around 600 HV1) slightly lower than untreated coating (around 625 HV1). The maintenance of high-level hardness for 1050 °C treated coating is attributed to the martensite matrix, fine newly precipitated carbides and hard inter-dendritic phases. The slight decrease of hardness of 1050 °C treated coating compared to untreated coating is caused by the weakness of residual stress and defects. Hardness of 650 °C treated coating decreases dramatically due to the decomposition of martensite into carbide and ferrite and weakness of residual stress and defects. However, the large amount of newly precipitated carbides can strengthen the material to a certain extent. The weakness of residual stress and defects by PCHT contributes better corrosion resistance in heated coatings than untreated coating. Austenizating at 1050 °C results in higher Cr content in martensite matrix than tempering at 650 °C, in which martensite transforms into ferrite and Cr-rich carbides. Thus, corrosion resistance of 1050 °C treated coating is stronger than 650 °C treated coating.