Laser Surface Melting and Consecutive Point-Mode Forging Hardening of DH36 Marine Steel: Mechanical and Precipitation Behavior

This study investigates the effect of laser surface melting and consecutive point-mode forging process (LSM-CPF) on mechanical properties microstructure DH36 marine steel. The microstructual revolution during LSM-CPF are revealed by metallographic microscope (OM) scanning electron (SEM) technique, strengthening mechanisms for different samples also elucidated. results show that best yield strength (σ0.2) tensile (σb) sample treated with 4000 W power 10% reduction ratio 721.3 884.2 MPa, which 49.55% 41.54% higher than matrix, respectively. hardness coatings decreases along normal direction maximum value 586.4 HV in CPF zone 2000 20% ratio. During low treatment, nanoscale cementite appear as intragranular due to inhibited carbon diffusion. coherent boundary (110)NbC‖(110)Ferrite, [11¯0]NbC‖[001]Ferrite between NbC ferrite reduces nucleation barrier promote acicular (AF). mechanism at is found be dislocation strengthening. high pearlite transformation occur a cooling rate. In this case, lamellar