Submerged arc surfacing of Ni–Co–Mo alloys similar to maraging steels on a structural steel

The manufacture of different machine and tool parts as a whole from expensive steels is often not cost-effective because of high costs of the material used and machining. It is, therefore, often reasonable to manufacture the parts from a cheaper and tougher structural steel and then surface the loaded surfaces with a layer of a high-quality wear-resistant alloy. A volume fraction of the surfaced layer with respect to the total part volume is very small and usually does not exceed 10%. This ensures an economic selection of materials and technologies with reference to the expensive materials. The paper presents the results of a study of submerged arc surfacing of Ni–Co–Mo alloys, related to commercial maraging steels, on a St 44-3 structural steel. The aim of our research was to produce a surface layer on the parts made from the structural steel and showing the properties typical of commercial maraging steels. To this purpose a cored wire and an alloyed agglomerated powder for surfacing the Ni–Co–Mo alloys with different chemical compositions were developed and produced. After surfacing with the home-made cored wire and alloyed agglomerated powder, the properties of the surface layers thus obtained were analysed. The research results include a chemical analysis of the surfaced layers, an analysis of the surfaced specimens with an optical microscope, and an analysis of through-depth microhardness of the specimens after surfacing and also after different temperature/time conditions of precipitation annealing.