Surface Structure Analysis of X12CrNiMoV12-3 and X6CrNiTi18-10 Steel Samples Processed by Laser Shot Peening (LSP)

¹ Centrum výzkumu Rez s.r.o., Morseova 1245/6, 301 00, Pilsen, Czech Republic
² Department of Material Science and Technology, University of West Bohemia, Univerzitni 8, 301 00 Pilsen, Czech Republic

^* Corresponding author: david.bricin@cvrez.cz, bricda@kmm.zcu.cz

Abstract

The aim of the experiment was to verify the influence of the chosen strategy of laser shot peening (LSP) on the structure and surface properties of samples made of martensitic steel X12CrNiMo12 and austenitic steel X6CrNiTi18-10. The analyses performed consisted of surface topography analysis of the samples, using a confocal microscope, Olympus LEX|T OLS 5000 and metallographic analysis using a Carl Zeiss Observer Z1m light microscope and a Tescan Mira 3 scanning electron microscope. The metallographic analysis was complemented by the measurement of microhardness HV0.01, which was performed using a Struers DuraScan semi-automatic hardness tester. The LSP process introduced plastic deformation into the surface layer of both materials analysed. The plasma and shock wave generated during the process further affected the surface roughness of both tested materials, which was reflected by an increase in the value of the roughness parameter Rz. Microhardness measurements showed that the influence of the LSP process can increase the surface hardness of the material. Metallographic analysis using light microscopy methods failed to identify differences between the structure near the shot peened surface and the non-peened surface, probably due to the coarse grain structure of both materials analysed.