Increasing the wear resistance of surface layers of selected steels by TIG electric arc surface remelting process using a powder based on CaCN 2

In technical practice, increasing wear resistance can be done in a variety of methods. However, most of them are technologically, time, and energy intensive, and the costs incurred frequently outweigh the benefits received. This study aims at surface modification of the selected grades of steels (25CrMo4, 30CrMoV9, 41CrAlMo7) through the TIG (tungsten inert gas) remelting process using a CaCN 2 -based powder. TIG remelting process was conducted in the shielding atmosphere of 99.996% argon (argon 4.6) at a gas flow of 10 l·min −1 and a welding current of 110 A. After remelting, the microstructure of the generated layers was analysed using scanning electron microscopy (SEM) and the hardness of newly formed layers was evaluated using a microhardness machine. In all of the tested steels, nitrogen had a favourable impact on the rise in hardenability, which resulted in a notable increase in hardness and resistance to abrasive wear. A significant increase in 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 the remelting process. The effect of nitrogen on the increase in the investigated properties is documented by a comparison of samples remelted in the absence and presence of CaCN 2 -based powder. The most significant increases of both parameters under investigation were attained in 25CrMo4 steel, which had the most considerable nitrogen enrichment. This method represents a cheap, technologically available, and fast way of forming surface layers with increased hardness and wear resistance, which makes it applicable in engineering, agriculture, earthworks, etc.