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42CrMo engineering common medium carbon alloy steel , widely used in the shafts, gear parts , quenched and tempered with superior mechanical properties , but its mechanical properties will change in the use temperature . In this paper, material testing machine of 42Cr. Mo quenched and tempered steel in . Quasi - static load as well as the mechanical properties of different strain rates in the range of 150 ~ 700 ℃ . The tests showed that the 42CrMo steel quenched and tempered with good ductility , lower temperature or strain rate , reduced plasticity of the material , but the intensity is increased , and found that the stress plateau in a temperature zone . By the scanning electron microscope , metallurgical microscope specimen fracture surface morphology and organization structure . The results showed little shallower depth of tiny dimples 150 ℃ , the temperature rises , the dimple increased, larger and deeper , quasi-cleavage facets gradually reduce the dimple 700 ° C is very dense , quasi- cleavage small plane has obvious . 42Ct-Mo steel quenched grain products organization sorbite axial deformation temperature increases , organizations grain size smaller . The use of dislocation motion theory , the the 42CrMo quenching and tempering of steel dynamics constitutive model . Non - thermal stress , thermal activation of the stress and viscous drag resistance of the flow stress . Simulation results show that the agreement of the model with the experimental data , it is possible to reflect the trend of plastic deformation , and display the flow stress in the plastic deformation process is mainly controlled by the non-thermal component and a thermal activation stress , viscous drag resistance is very small , compared to the J-C equation simulation results , the model can reflect the characteristics of the plastic deformation of the low strain rate at different temperatures . Analysis based on the theory of dislocation motion movement and to explore the behavior of the plastic deformation of the metal test stress plateau needs to meet a certain temperature and J strain rate conditions cough now edge t due to dislocation motion process over by solute atoms pinning effect .
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