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通过对Deform-3D软件二次开发,模拟研究了新型节镍奥氏体耐热钢21Cr-11Ni-N-RE大口径厚壁管热挤压过程中晶粒演变规律,并引入晶粒组织不均匀因子Z,评估了不同坯料预热温度、挤压速度、挤压比下晶粒组织均匀性。结果表明:增加坯料预热温度、提高挤压速度、增大挤压比均使得晶粒组织不均匀因子Z降低,即有利于提高晶粒组织均匀性。通过正交优化合理选择了热挤压参数,并实际获得了具有均匀晶粒组织的大口径厚壁管。晶粒组织的有限元模拟结果与实际测量值吻合较好,验证了有限元模型的正确性与可靠性。
Through the secondary development of Deform-3D software, the grain evolution of 21Cr-11Ni-N-RE large-caliber thick-walled tube with hot-pressed Ni-austenitic heat-resistant steel was simulated and the grain structure was not introduced Uniformity factor Z was used to evaluate the homogeneity of grain structure under different preheating temperature, extrusion speed and extrusion ratio. The results show that increasing the preheating temperature, increasing the extrusion speed and increasing the extrusion ratio all reduce the nonuniform grain size Z, which is beneficial to improve the homogeneity of the grain structure. By orthogonal optimization, the hot extrusion parameters were selected reasonably and the large diameter thick-walled tubes with uniform grain structure were obtained. The simulation results of the grain structure agree well with the actual measured values, which verify the correctness and reliability of the finite element model.