Cailiao gongcheng (Dec 2022)
Dynamic and high temperature mechanical behavior of GCr15SiMo steel
Abstract
The effect law of heat treatment process on the microstructure of GCr15SiMo steel was studied, and the dynamic and high temperature mechanical behavior of GCr15SiMo steel with different microstructure was analyzed by using Hopkinson rod and GNT100-2 high temperature tensile testing machine. The results show that the mass fraction of M3C-type carbide particles of GCr15SiMo steel decreases from 2.319% to 0% when the quenching temperature increases from 800 ℃ to 920 ℃; the failure strains of GCr15SiMo steel all increase with the increase of strain rate during dynamic compression.When the true strain is 0.2 and 0.8, the rheological stress of GCr15SiMo steel decreases by 13.45%, 21.44%, 27.49% and 31.79% respectively with the increase of quenching temperature. The accelerated decrease of rheological stress is mainly related to the structure and adiabatic shear mechanism during dynamic compression deformation; at high strain rate, the macroscopic deformation of GCr15SiMo steel changes from pier coarseness to shear failure along 45°, the adiabatic shear mechanism is one of the main reasons for the change in deformation behavior, and the structure is one of the key factors affecting the sensitivity to adiabatic shear; during dynamic compression deformation of GCr15SiMo steel, the deformation temperature rises between 117 ℃ and 333 ℃, and the M3C carbide particle re-solution is one of the key factors for the increase of tensile strength and decrease of yield strength of high temperature performance. When the quenching temperature is 920 ℃, the microstructure of GCr15SiMo steel is uniform twin martensite. The subgrain boundaries in the twin crystal martensite can effectively impede the dislocation movement, which show obvious strain hardening phenomenon under the tensile stress, and the stress-strain curve shows a more significant rising trend than that at quenching temperature of 800 ℃.
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