Research on the Influence of Laser Power on the Microstructure and Performance of Fe-Based Coating

Abstract

For the poor working environment, there would easily be sprocket tooth nest corrosion wear failure of mining sprocket, based on coaxial powder feeding method, this study prepares Fe-based alloy cladding on the surface of 42CrMo, which further improves the performance of the substrate. The effects of laser power on the dilution rate, microstructure, hardness and corrosion resistance of Fe-based alloy coating and the effect of heat treatment on the tensile properties of the cladding layer were studied. The results show that, with the increase in laser power, the grain size of the cladding layer becomes larger. When the laser power is greater than 1900 W, the cladding layer generates Fe₂B and Cr₂₃C₆; the average hardness of the coating with laser power of 1600 W is the highest, which is 586.86 HV. Electrochemical experiments show that the 1800 W coating has excellent corrosion resistance, high corrosion potential (− 0.42 V) and minimum corrosion current density (2.65 × 10⁻⁶A·cm⁻²). EDS results show that no obvious corrosion area is found on the surface of the 1800 W cladding layer. This excellent performance is attributed to the formation of a dense Cr₂O₃ passivation film on the surface of the cladding layer. The tensile test shows that the coating heat treated at 700 °C has the best tensile properties.