Parameter Optimization and Mechanical Properties of Laser Cladding of 316L Stainless Steel Powder on G20Mn5QT Steel

Abstract

G20Mn5QT steel has excellent mechanical properties and is widely used in key components of rail vehicles. However, during the operation of high-speed vehicles, wear and tear will inevitably occur. In this paper, laser cladding technology was selected to successfully prepare 316L stainless steel coating. The optimum processing parameters were obtained with a laser power of 2300 W, a scanning speed of 500 mm/min, and a powder feeding speed of 14 g/min. The microstructure of 316L coating is mainly composed of planar crystals, cellular crystals, columnar crystals, and equiaxed crystals. Through range analysis, it is found that the microhardness, wear resistance, and micro-shear strength of the cladding layers increase with the increase of laser power, while the tensile strength and yield strength increase first and then decrease with the increase of laser power. Under the optimized process parameters, the low-temperature impact toughness, elongation, tensile strength, and yield strength of the cladding layer were 97.6%, 24%, 10.9%, and 32.5% higher than that of the G20Mn5QT substrate, respectively. An excellent combination of strength and toughness was achieved by cladding 316L alloy on the surface of the G20Mn5QT substrate, which can meet the requirements of remanufacturing fractional key vehicle parts.