Effects of softening annealing and spheroidal annealing on the characteristics of precipitates,microstructure and mechanical properties of hot rolled 30Cr15Mo1N steel wire after quenching,cryogenic treatment and tempering were comparatively studied.The results show that precipitates after annealing are Cr2(C,N)and M23 C6,where the spheroidal annealed specimen has a smaller size of precipitates,better spheroidizing effect,and more uniform distribution.The softening annealed specimen has higher strength,its tensile strength is 819 MPa,63 MPa higher than that of the spheroidal annealed specimen,and the spheroidal annealed specimen shows discontinuous yield phenomenon during tensile process.The more precipitates in the softening annealed specimen effectively inhibit grain growth during the reheating process,resulting in finer grain size after heat treatment,and the hardness is 61.4 HRC,which is higher than that of the spheroidal annealed specimen.
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