Microstructure and mechanical properties of surface-strengthened DP980 after different shot peening strengths

This study investigates the effect of different shot peening (SP) strengths on the microstructure, mechanical properties, and wear resistance of DP980 steel. Based on the analysis of the microstructure, mechanical properties, and wear resistance, the following conclusions are drawn: (1) When the SP strengths are 0.3MPa, 0.45MPa, and 0.6MPa, the thicknesses of the plastic deformation layer are approximately 18.48 µm, 44.1µm, and 57.48µm, respectively. After SP, the surface roughness increases, and the height difference on the sample surface reaches its maximum value of approximately 170.1µm at 0.6MPa. (2) When the SP strength increases from 0MPa to 0.6MPa, the average hardness value increases from approximately 289.4HV to 378.3HV, which is mainly due to grain refinement. (3) As the SP strength increases from 0 MPa to 0.6 MPa, the average coefficient of friction decreases from 0.2102 to 0.1470. Meanwhile, the wear rate shows a similar decreasing trend. This indicates that the wear resistance of DP980 is improved after SP.