Abstract: Three kinds of Fe-Cr-Mo-W-V hot working die steels (DM, H21 and H13) were prepared to investigate the thermal stability at 580—650 ℃. Utilizing the hardness measurement and scanning electron microscopy (SEM), an attempt was made to study the thermal stability of three hot working die steels. The results indicated that DM steel had a higher thermal stability than H21 and H13 steels during tempering. Besides, combined with transmission electron microscopy (TEM), the dilatometric data (conti-nuous heating transformation curves) during tempering were analyzed to determine the significance carbides resulting in high thermal stability in Fe-Cr-Mo-W-V steels. To improve the understanding of the thermal stability mechanism, the activation energy of the transformation of MC carbides from M2C carbides in DM, H21 and H13 steels were determined as 163.9—204.1 kJ/mol, which reflect the diffusion of the solute atoms in the transformation reaction of M2C and MC carbides is controlled by volume diffusion and dislocation pipe diffusion, DM steel own the highest activation energy as 204.1 kJ/mol. Furthermore, comparing the differences of the value electron structures in three steels, DM steel with excellent thermal stability shows the best electron structure.
施渊吉, 吴晓春, 闵娜. Fe-Cr-Mo-W-V系热作模具钢高温热稳定性机理研究[J]. 材料导报, 2018, 32(6): 930-936.
SHI Yuanji, WU Xiaochun, MIN Na. Thermal Stability Mechanism of Fe-Cr-Mo-W-V Hot Working Die Steel. Materials Reports, 2018, 32(6): 930-936.
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