Research Of Laser Technology On 45 Steel Surface Modification

Invalidation of mould steel starts from the surface. Therefore, improving the surface structure and mechanical performance is an effective way to extend mould operating life. By applying the laser quenching and laser cladding on strengthening the surface of mould steel, the wearability, corrosion resistance, high thermal performance, inoxidability of the mould surface can be improved. And this will also improve the mould quality and extend operating life, which has a great economic and social benefit.In the present paper, the laser surface quenching of No. 45 Steel is done with the help of LWS-500 laser welding machine, the research of which analyzes the quality of laser quenching under different laser scanning velocity. The surface laser of No. 45 Steel is clad with the powder of ultratek containing TiC Ceramic particles. By observing the microstructure and measurement microhardness, the paper explores the effects of Ni/TiC mixture ratio on microstructure and microhardness of the cladding metallographical structure. In addition, the paper also analyzes the effects of different laser scanning velocity and powder granularity on cladding layer cracks, stomata, etc.The results show that laser quenching and laser cladding technology can improve the surface structure and performance of No. 45 Steel effectively, which has a broad prospect of application. When the laser scanning speed is 2mm/s, the quality reaches the best with 320μm hardening layer and 71.2HRC surface hardness. If Ni60+20%Tic alloy powder is used in laser cladding, it can get best quality of cladding layer with better cladding performance and microstructure density. When laser scanning velocity is reduced, there will be some retarding effect on cladding layer cracks and stomata. When the scanning speed is 4mm/s, the defects of cladding layer cracks and stomata are the least, the microhardness of which can reach 862HV. Powder granularity can also influence the defects of cladding layer cracks and stomata. When the granularity is small and the mixture even, cladding performance of the laser cladding layer and microscopic density will be better and defects like cracks and stomata etc. will be reduced.