Dislocation-intervening carbides mechanism and its impact on the corrosion resistance of 304/Q235 composites

Abstract

Stainless steel clad plates are highly sought after in industries such as heavy machinery, ships, and pressure vessels. Intergranular corrosion, caused by the uphill diffusion of carbon atoms, hinders the progress of stainless steel composite plates. The controlled rolling and post-deformation of the solution-free treatment described in this paper inhibits the Segregation behavior of alloying elements, leading to increased resistance to intergranular corrosion and improved pitting corrosion ability in the 304/Q235 composites. The intergranular corrosion rate and corrosion potential of the 304/Q235 composites were 792 g/(m²·h) and −473.3 mV_SCE, respectively, in their original hot rolled state. The introduction of high-density dislocations before the formation of chromium-rich carbides can hinder the precipitation of carbides along grain boundaries, resulting in an 18·3% reduction in the intergranular corrosion rate of the composite plate. Cold deformation is performed following the precipitation of chromium-rich carbides, resulting in a decrease in the degree of aggregation of C, Cr, and other elements. The aforementioned process described above results in a discontinuous distribution of carbides along grain boundaries, as well as the refinement and dissolution of the precipitation phase. The intergranular corrosion rate of the deformation-treated composite plate was reduced by 79 g/(m²·h) in comparison to its initial hot-rolled state. The aim of this study is to elucidate the underlying mechanism by which deformation influences the carbide precipitation behavior of stainless steel composite plates. This research provides a novel idea for the cost-effective and solution-free hot rolling preparation of stainless steel composite plates.