Transactions of Materials and Heat Treatment

Title：Establishment of twostage constitutive model for SA508Gr.4N nuclear power steel and simulation of final forging for tube sheet

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ClassificationCode：TG316.2

year,vol(issue):pagenumber：2020,45(4):1-13

Abstract：

Using the real stress-real strain data of the new generation for nuclear power material SA508Gr.4N steel, the two-stage flow stress constitutive model was established based on temperature, strain and strain rate of material. And the related coefficient R and the absolute average relative error AARE were introduced to verify the predictive ability of the constitutive model, which were found to be 0.9916 and 5.07%, respectively. Adopting the constitutive model for secondary development, subprograms based on Fortran language were written and embedded in DEFORM software. Combined with measured thermal property parameters such as thermal conductivity and specific heat capacity of SA508Gr.4N steel which changed with temperature, the key final forging of heavy forgings for tube sheet of nuclear power key parts were simulated systematically, including the three sub-processes: the flat hammer head widening, the flattening boss and the rotary compaction. The temperature field, the stress field, the equivalent strain field and the final forming performance of forgings under different process parameters during the hot forging process were analyzed. Finally, a reasonable forging process schem is obtained.

Funds：

广东省自然科学基金团队资助项目(2015A030312003)

曾志钦(1994-)，男，硕士研究生 E-mail：mezqzeng@scut.edu.cn 通讯作者：张卫文(1969-)，男，博士，教授 E-mail：mewzhang@scut.edu.cn

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