Modification of Diffusion Layers by Laser Shock Peening

Laser cladding technology is used to clad the surface layer of H13 mold steel with Ni60A metal powder coating to solve the failure problem. The study used JMatPro software to extract and fit the thermophysical property parameters of the substrate and the clad material, and then used ANSYS APDL software to qualitatively analyze the distribution of melt pool morphology, nodal temperature versus time course curve and residual stress magnitude during the laser cladding process. Based on the results of the minimum residual stress in the cladding, reasonable scan paths were derived for the preparation of metal coatings on the surface layer of the die steel. The results show that the maximum peak temperature of the cladding process is 2515°C using short path scanning. The cladding layer can form a good metallurgical bond with the substrate at this temperature, with a stress of 406.68 MPa in the scanning direction and 284.45 MPa perpendicular to the scanning direction, which is significantly smaller than the residual stresses of other scanning methods. The residual stress values for the different strategies are from largest to smallest: spiral scan, block scan, long path scan, and short path scan. The results of this study provide theoretical guidance for the selection of paths during cladding processing to reduce the waste of resources and also provide new ideas for exploring the feasibility of metallurgical bonding of materials to substrates.

Effect on Surface Properties of H13 Mold Steel Cladding Layer by Scanning Strategy

Zhao¹,

Yang²,

Li³

et al. 2023

Analysis of the Coating Delamination after Laser Beam Cutting

Mičietová,

Neslušan,

Florková

et al. 2023

This paper analyses surface after laser beam machining with respect of surface height irregularities, residual stress state as well as microstructure on the low alloyed steel S 235. Surface after laser beam machining is investigated due to its specific nature resulting into coating delamination. This coating delamination can be found especially in the regions in which component shape or/and curvature of the profile is altered. Especially the components corners suffer from the delamination due to extensive surface heating and presence of brittle oxides layer. The thickness of this oxides layer is heterogeneous with respect of the component thickness as well as the component geometry. It was found the oxides layer is the thermally initiated process since in these regions the underlying matrix also exhibits the higher thickness of the heat affected zone and higher degree of the hardening expressed in term of HV0.1. Furthermore, also the compressive residual stresses exhibit higher amplitudes in the region remarkably affected by the thermal cycle.

Effect of Laser Shock Peening on the Microstructure of P265GH Steel and X6CrNiTi18-10 Stainless Steel Dissimilar Welds

Bricín,

Špirit,

Gilík

et al. 2024

The aim of this study was to verify the laser shock peening (LSP) on the microstructure of P265GH steel and X6CrNiTi18-10 stainless steel. The LSP surface treatment was done underwater on the dis-similar weld joint of the P265GH and X6CrNiTi18-10 tubes. The metallographic analysis then focuses on the evaluation of microstructure in heat-affected zones of both materials. The results of our analysis are possibly summarised as follows. Light and scanning electron microscopy have shown grain refinement in the treated surface of the HAZ region of X6CrNiTi18-10 steel. For P265GH steel, it was possible to find a remelted surface layer with a thickness of 3.3±0.6 micrometers in the peened areas. For P265GH steel was also possible to observe a significant increase in deformation in the grains with straight contact with the peened surface by EBSD analysis. In the case of X6CrNiTi18-10 steel, this area extended to a depth of over 50 micrometers from the peened surface.