ENHANCING SURFACE PROPERTIES OF 34Ni-Cr-Mo6 STEEL THROUGH LASER TREATMENT VARIATIONS: A COMPREHENSIVE CHARACTERIZATION STUDY

Laser-based surface enhancement techniques improve metals’ mechanical properties. Laser Hardening (LH) and Laser Shock Peening (LSP) techniques are effective particularly well with low-alloy steel made of 34Ni-Cr-Mo6, which is a type of steel alloy that is put to use in a wide variety of fields because it possesses excellent levels of both strength and toughness. For specific applications, the laser can be shaped into line or spherical beams. On the other hand, typical industrial requirements of low alloy steel components like 34Ni-Cr-Mo6 are enhanced hardness and mechanical strength with minimum or no distortion. A 3 kW high power fiber laser with a flat top-hat beam of dimension [Formula: see text] [Formula: see text]mm and a circular beam of Ø6[Formula: see text]mm are employed in this study. Investigation into the effects of repeated LSP on the microstructures and residual stress of 34Ni-Cr-Mo6 low alloy steel was also done. LSP treatment is carried out at 6.36[Formula: see text]GWcm[Formula: see text] Laser Power Density (LPD) with different laser impacts, i.e. single and double, by keeping 0% overlap along the scanning direction and perpendicular directions, respectively. The shock-peened samples were characterized in terms of residual stress measurements and microstructural evolution using different characterization techniques. A substantial improvement in compressive residual stress was observed at the hardened cross-section i.e. [Formula: see text] [Formula: see text]MPa and at shock peened surface [Formula: see text] [Formula: see text]MPa respectively as compared to the as-received sample ([Formula: see text] [Formula: see text]MPa). LH samples showed a better result in terms of microhardness values when compared to shock peened samples i.e. for LH, the microhardness values at the cross-section were [Formula: see text] [Formula: see text]HV[Formula: see text] nearly 2.5 times increase in hardness. Extreme plastic deformation was found by microstructural examination of cross-sections of LSP-treated areas. Hardness was nearly marginally improved in multiple times LSP-treated samples compared to unpeened ones as a result of LSP.