Research on the Microstructure and Properties of Fe-based Alloy Coatings Under High-power Lasers

ZHANG Jun; WANG Jingyu; YUAN Haoyu; ZHUANG Lili; HUO Fujun; REN Ziting

doi:10.16545/j.cnki.cmet.2025.01.009

Abstract：Laser cladding technology generally uses high laser power in practical applications of enterprises.Reasonable combination of process parameters can produce coatings with good performance.In enterprises,parameters are usually matched based on experience,and the quality of the cladding layer sometimes cannot meet the standards.In order to help enterprises obtain reasonable process parameter combinations,the influence of different laser powers and scanning speeds on the performance of fusion coatings was studied.Three orthogonal experiments were designed with three different laser powers and three different scanning speeds to prepare Fe-based alloy fusion coatings on the surface of column base material 27SiMn steel using a single-layer and multi-channel fusion method under high-power rectangular spot conditions.Then,the metallographic structure,surface hardness,and corrosion resistance of the fusion coatings were studied.The experimental results showed that a good metallurgical bond was formed between the cladding layer and the substrate.The microstructure of the cladding layer was mainly characterized by columnar crystals and equiaxed crystals,with a large unit cell area and consistent growth direction.The microstructure is relatively uniform,and the upper part of the cladding layer is denser than the lower part.The surface hardness of the column base material 27SiMn steel is about 23 HRC.When the laser power is 12 000 W and the scanning speed is 500 mm/min,the thickness of the cladding layer is about 2 mm,and the surface hardness of the cladding coating is about 56.2 HRC,which is more than twice that of the substrate.The corrosion resistance of the cladding layer is significantly improved compared to the substrate,and the corrosion effect is more severe in the overlapping area of the cladding layer.