Abstract: Ultrasonic deep rolling(UDR) technique is applied to treating electric arc spray 3Cr13 coating to improve its overall properties. The influence of UDR treatment on coating porosity, surface roughness, residual stresses, microhardness, inherent strength and tribological property of the coating is investigated by using scanning electron microscope, X-Ray stress instrument, ball-on-disc friction and wear tester, etc. Results of the tests show the distinct improvement on the overall properties of the UDR treated coating: The porosity decreases from 5.1% to 2.3%, surface roughness decreases from more than 40 μm to 2.4 μm, surface compressive residual stresses increases from 8 MPa to 257 MPa, microhardness increases about 45% and wear resistance increases obviously. The X-ray diffraction experimental results show that the peak of Bragg diffraction pattern is broadened evidently and the intensity of the peak also increases evidently as a result of UDR treatment, which indicates the refinement of coating grain and the distortion of lattice, and the formation of a sheet texture surface with parallel lattice orientation. At the same time, the effect mechanism of UDR treatment on the properties of the coating is discussed and analyzed.

Key words: 3Cr13 coating, Electric arc spray, Properties, Ultrasonic deep rolling, Load distribution, Load transfer, load-carrying capacity, Vehicle body frame