There are some regular welding cracks on the bimetallic chromium carbide overlay plate surface. From front side, cracks are perpendicular to the weld direction, from the cross section, cracks go through the wear resistant layer thickness direction and stop at the fusion line, there is no welding cracks on the base plate. External stress and stress concentration are the essential prerequisite of these welding cracks.

As we know, wear resistant layer is composed of matrix and carbides, and there is an mechanical combination between them. Carbide can be seen as welding defects-slag, which is the stress concentration point, is the source of crack. Welding process of bimetallic chromium carbide overlay plate is an nonuniform heating process,so it will have great welding residual stress during welding. The lateral stress is compression stress and cause plastic deformation, so that the horizontal size of wear plate is shortened, but will not cause crack. Longitudinal stress is tensile stress, stress level is close to the material yield strength. Usually, the cracks does not affect the wear resistance ability of chromium carbide overlay plate.

Crack can indirectly reflect the wear resistance of the bimetallic wear resistant steel plate, we can make a preliminary judgment on the wear resistant steel plate quality according to the cracks. Normally, for the same type CCO plate, the regular smaller cracks the better wear resistance it is, because carbides in the wear resistant layer is tiny and organized in a certain pattern. Otherwise, wear resistance is poor.