Abstract
The influence of non-metallic inclusions on the corrosion resistance of stainless steel of the austenitic-martensitic class, deposited in one layer with flux-cored wire under the flux by the arc method in the mode of stationary and pulsed arc burning, has been studied. In the latter case, the wire feed impulse was 0.5 and 0.7 Hz. The selected surfacing conditions, with both methods of the process, contribute to the formation of non-metallic inclusions of complex composition and structure in the deposited metal, including those containing calcium and its compounds with other elements, which are classified as corrosive, accelerating the occurrence of corrosion phenomena.
Highlights
In recent years, surface engineering has gained more importance in the field of materials science, especially in the aerospace, automotive, biomedical, and engineering fields [Mikhalev 2019, Pogrebjak 2016, Dyadyura 2017, Sukhodub 2019]
The activity of the metal in the places of its contact with non-metallic inclusions can be due to various reasons, such as: increased defectiveness of the crystal lattice of the metal near the inclusion, depletion of this layer in corrosion-resistant alloying components of the alloy, activating the effect of the dissolution products of the NI itself, the presence of a gap between the inclusions and the metal
The presence of calcium in non-metallic inclusions of the deposited metal poses the task of assessing their detection methods, the effect on the corrosion rate of stainless steels, and understanding the phenomena occurring in this case
Summary
Surface engineering has gained more importance in the field of materials science, especially in the aerospace, automotive, biomedical, and engineering fields [Mikhalev 2019, Pogrebjak 2016, Dyadyura 2017, Sukhodub 2019]. In the study [Kychkin 2019], the role of local austenite zones in the near-surface layers of austenite-martensitic metal of deposited beads on the development of corrosion processes along the boundaries of austenite grains was shown This effect was observed both in conventional methods of arc surfacing with flux-cored wire and in pulsed-arc surfacing, in the latter case, the metal is formed with less structural micro-inhomogeneity. Without denying the negative effect on the corrosion processes of oxysulfides, especially of large sizes, it is considered that the most dangerous are inclusions of FeS and MnS These inclusions, having a coefficient of linear expansion greater than that of the matrix, form a microvoid at the metalinclusion boundary when the steel is cooled after solidification of the weld pool metal. In corrosive environments, sulfides play the role of microcathode regions leading to local destruction of the metal
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