Effect of laser shock peening on microstructure and mechanical properties of laser cladding 30CrMnSiNi2A high-strength steel

Abstract

The effect of laser shock peening (LSP) on the microhardness and tensile properties of laser cladding (LC) 30CrMnSiNi2A high-strength steel was studied. After LSP, the microhardness of the cladding zone reached approximately 800 HV0.2, which was 25% higher than that of the substrate, while the cladding zone without LSP had an approximately 18% increase in its microhardness. Two strengthening processes were designed: groove LSP + LC + surface LSP versus LC + surface LSP. The former's tensile strength and yield strength were less than 10% weaker than those of forged materials, which is the best mechanical property recovery found in LC samples. The microstructural characteristics of the LC samples were analysed by scanning electron microscopy (SEM) and electron backscatter diffraction. Under the action of the laser-induced shock wave, the grain size of the LC sample surface was refined, the low-angle grain boundaries on the surface layer increased significantly, and the austenite grain length was reduced from 30–40 μm in the deep layer to 4–8 μm in the surface layer. In addition, LSP modulated the residual stress field, hence preventing the weakening effect of the LC process's thermal stress on the components' mechanical properties.

Laser Shock Peening: Fundamentals and Mechanisms of Metallic Material Wear Resistance Improvement

“…Zhou et al [36] investigated the lodging of pre-coated nanopowders into the near-surface layer of IN718 SPF superalloy material by using LSP-induced GPa pressure to enhance surface hardness. Wang et al [37] investigated the microhardness of LC-treated 30CrMnSiNi2A high-strength steel after LSP treatment, which resulted in being 25% higher than that of the substrate. In their work, Tong et al [38] utilized the LSP technique to modify the residual stress state and microstructure of Cr-Mn-Fe-Co-Ni HEA surface layers fabricated by using laser-directed energy deposition; they found a variation in the surface residual stress state from tensile residual stress to compressive residual stress in the LSP-treated specimens, and they observed the closing of pores in the surface layers due to severe plastic deformation (SPD).…”

Effect of Metallic Coatings on the Wear Performance and Mechanism of 30CrMnSiNi2A Steel

“…The current literature on the 30CrMnSiN2A material focuses mainly on fatigue life and mechanical properties [ 18 , 19 , 20 , 21 , 22 , 23 ], with barely any attention paid to the wear resistance. Xue et al [ 24 ] investigated the wear resistance of 30CrMnSiNi2A and analyzed the wear mechanisms under different loads and friction speeds.…”