Characteristics of alternating current field enhanced pack boriding for S32750 duplex stainless steel at medium temperature

doi:10.13251/j.issn.0254-6051.2024.07.026

Abstract

Abstract: Conventional pack boriding (CPB) and alternating current field enhanced pack boriding (ACFPB) were performed at 800 ℃ on S32750 duplex stainless steel, and an ACFPB treated specimen was later subjected to solution treatment. The microstructure, thickness, hardness and phase structure of the borided layer were investigated by optical microscope, X-ray diffraction and microhardness testing, respectively. The results show that the morphology of the ACFPB layer is similar to that of the CPB layer, with a flat front and good bonding with the substrate, and the surface layer is composed of mainly FeB. Applying alternating current field (ACF) during boriding can effectively promote the diffusion of boron and increase the hardness of the borided layer. However, when the current increases to 6 A, more micropores appear in the borided layer. The solution treatment for the 5 A ACFPB treated S32750 steel results in a slight increase in the thickness of the borided layer, a significant decrease in the amount of FeB phase, an increase in the amount of Fe₂B, and the precipitated phase σ formed during boriding is dissolved into the matrix, which helps to improve the toughness of the duplex stainless steel.

Key words: S32750 duplex stainless steel, pack boriding, alternating current field

CLC Number:

TG156.8⁺7

Wu Xianlong, Xie Fei. Characteristics of alternating current field enhanced pack boriding for S32750 duplex stainless steel at medium temperature[J]. Heat Treatment of Metals, 2024, 49(7): 168-172.

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