DEPTH STRUCTURE OF WEAR RESISTANCE COATING ON STEEL OBTAINED BY ELECTRIC ARC METHOD

It has been shown by scanning electron microscopy that the formation of the deposit facing on steel surface is accompanied by the creation of a multilayer structure including a layer of welding, transition layer and layer of the heat-affected zone. Crystallization of facing is accompanied by the formation of a columnar structure, which presents alternating layers of two types of thickness 8 – 10 microns. Layers of the first type are characterized by a lamellar structure oriented perpendicular to the substrate surface, the thickness of the separating plates and intermediate layers in the layer varies in the range of 50 – 100 nm. Layers of the second type have a structure of lamellar and globular type. On a distance from the surface facing the lamellar structure of the first type layers degenerates and completely disappears on the border with the transitional layer. The globules sizes vary in the range of 1.5 – 3.0 microns, globules are fragmented. The gradient nature of the structure is identified in the transition layer and the heat-affected zone also. It was established that the boundary facing – steel is in elastically stressed state, formed as a consequence of ultra-high heating and cooling velocities; this was evidenced by the presence of micropores and microcracks, located line-by-line, as well as by extended intermediate layers of the second phase.

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