Laser-plasma surface modification of steels and Fe-based alloys

This paper presents the results of experimental research concerning the laser-plasma processing (hardening) of the following steel grades: 65Mn, 40Cr, GCr15, 30CrMnSiA, grade “2” steel used in accordance with GOST 398-2010 in production of wheel tyres for railway locomotives; as well as alloys Fe71.75C4.81Cr3.33Si3.54B14.10Mn1.74V0.73 and Fe66.8Mn2.84C2.85Si5.3B11.42Cr10.79 in addition to the aforementioned. It is shown that the thickness of the hardened layer of processed steels is dependent on the processing mode and varies between 0.3-1 mm, while its hardness reaches values of 10-14 GPa, 2-4 times higher than the base material. The sample studies of the grade “2” steel after the processing have demonstrated the substantial increase (by approx. 10 times) in wear resistance. The laser-plasma processing of alloys leads to the formation of a fine-crystalline layer with a characteristic crystallite size of 0.5-1 µm and a thickness of 3-5 µm. The hardness of said layer is increased by approx. 1.2 times.