Investigation of abnormal wear of massive machine part-welded-technical chromium layer system

The aim of the investigation was to establish the reason for accelerated destruction of the technical chromium layer coated electrochemically over a large cylindrical machine part, operating under changing environmental/acidity conditions. The deterioration takes the form of local flake-offs of the chromium layer and formation of peripheral corrosion groove in the region of the welded join connecting the cylindrical machine part with the disk of the press plunger. As a result of the detailed studies which were carried out, several technological and design reasons for accelerated destruction of the costly machine part have been identified. This paper presents the results of the investigation into the distribution of elements such as C, Si, Mn, Cu, Cr, and V in the region adjacent to the weld face, and in the core of the welded zone in the direction perpendicular to the weld face. The effect of changing chemical composition in the welded region is discussed, outlining the role of each element. Metallographic microscopic and spectrometric studies have enabled the formulation of several conclusions bearing on the complex mechanisms leading to local deterioration and seizure of a large expensive machine component.