Creation of wear-resistant layers on steels using TIG electric arc surface remelting process with applying CaCN2-based nitriding powder

Abstract

Tungsten inert gas (TIG) electric arc welding process was used for surface remelting of nitriding powder applied on selected steel grades. The influence of remelting on the chemical composition and microstructure changes in the remelted area of selected steels (25CrMo4, 30CrMoV9, 41CrAlMo7) with different content of nitride-forming elements (Al, V) was investigated to improve hardness and abrasion wear resistance. Nitriding powder Pulnierpulver based on calcium cyanamide (CaCN2) was used in remelting. Hardness measurements and determination of abrasive wear resistance on an abrasive cloth with Al2O3 particles were performed. The microstructures of the remelted layers, as well as the worn areas, were observed by SEM. The presence of nitrogen in the remelted layers was proved by EDX analysis. A significant increase of hardness and abrasive wear resistance was achieved up to a depth of 1–1.5 mm from the surface in the case of all steels through remelting process. These results obtained can be attributed to the significant effect of nitrogen on the hardenability increasing of remelted layers and alloying martensite with nitrogen. The most significant growths of both parameters investigated were achieved in 25CrMo4 steel, for which the most significant nitrogen enrichment was found. The presented process of TIG surface remelting with powders containing a particular element represents a cheap, affordable, and fast way of forming surface layers with improved hardness and wear resistance.