Ultrasonic surface rolling process (USRP) combined with deep cryogenic treatment (USRP+DCT) was applied on quenched and tempered Cr12MoV. The results indicated that USRP and USRP+DCT could significantly improve the surface mechanical properties, leading to smaller surface roughness and smoother morphology with less cracks and defects. Test of microhardness showed that the hardness increase of USRP and USRP+DCT were 16.4% and 23.6%, respectively. In addition, the wear resistance was improved by USRP and USRP+DCT. Compared with USRP, USRP+DCT can further improve the surface mechanical properties of Cr12MoV.

The effect of high temperature annealing on microstructure evolution of Ni-24Fe-14Cr-8Mo alloy was investigated through Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Rockwell Hardness Testing Machine. Three kinds of grain growth patterns were found at different annealing temperatures due to carbides precipitation and dissolution. After a combination of high temperature annealing and aging treatment, the hardness versus time curves performed a parabolic pattern. The highest hardness was achieved under 1070°C/60 minutes treatment, and the desirable annealing time should be 60 minutes to 90 minutes.