Cailiao Baohu (Feb 2025)

Study on the Microstructure and Performance of Iron-Based Alloy Coatings on the Inner Surface of Conveying Pipes via High-Speed Laser Cladding

  • LUO Heng, YAN Zongliang, KAN Chaoyu, YANG Chicheng, ZHANG Ziqi, CHEN Zipeng

DOI
https://doi.org/10.16577/j.issn.1001-1560.2025.0031
Journal volume & issue
Vol. 58, no. 2
pp. 123 – 130

Abstract

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In order to address the issue of wall failure due to impact abrasion during the use of conveying pipes， a high-speed laser cladding(HLC) technique was employed to prepare a JG-3 iron-based coating on 20CrMo steel， a commonly used material for conveying pipes.The surface morphology， microstructure， phase composition， elemental distribution between dendrites and interdendritic regions， coating hardness and wear resistance of the JG-3 iron-based coating prepared by HLC were analyzed and compared with coatings produced by conventional laser cladding (LC).Results showed that the HLC coating was narrow and thin， with less noticeable overlapping tracks on its surface.The macro surface was smoother， and the surface roughness of the HLC coating was reduced by 49%compared to the LC coating.No significant defects were observed within the coating， the transition zone between elements was small， and a good metallurgical bond was formed between the coating and the substrate with a low dilution rate.The microstructure was dense and transitioned from planar crystals to columnar crystals to cellular crystals from bottom to top.In contrast， the conventional laser cladding coating had pores， coarse structure， and disordered growth directions.Although the high-speed laser cladding technique did not change the phase composition of the coating， the content of the γ (Ni-Cr-Fe) solid solution phase formed in the coating was significantly increased， which resulted in an average microhardness of the HLC coating reaching 837.4 HV0.2， which was 1.33 times that of the LC coating.Furthermore，under the same friction and wear conditions，the weight loss of the HLC coating was 6.2 mg， approximately 30%of the LC coating and 13%of the substrate.Compared with the conventional laser cladding technology， the JG-3 iron-based coating prepared by the high-speed laser cladding technique significantly improved the surface performance of conveying pipes， effectively extending their service life.This work provides a new approach to improving the wear resistance of conveying pipe surfaces.

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