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基于铸坯的环件径轴向辗轧成形新技术面临的瓶颈问题,对坯料铸态组织的演变规律与合理控制进行研究。对某环件双向轧制,铸坯的尺寸将决定变形程度和径、轴向的变形量分配,从而对最终环件的组织起着至关重要的作用。该文基于ABAQUS平台,建立了42CrMo钢铸坯环件径轴向热辗轧宏微观耦合有限元模型;采用一种基于轧比K和径轴向变形量分配比tanα的坯料尺寸设计方法,针对同一环件的轧制过程,设计具有不同K和tanα值的不同尺寸的多个环坯,模拟不同铸态42CrMo坯料尺寸下环件径轴向辗轧过程组织的演变规律。结果表明,随着K值增大,环件动态再结晶程度增加,平均晶粒尺寸减小且分布逐渐均匀;随着tanα值增大,环件上下端面区域动态再结晶程度增大,平均晶粒尺寸减小,沿环件轴向平均晶粒尺寸分布逐渐不均匀,而内外表面区域动态再结晶程度减小,平均晶粒尺寸增大,沿环件径向平均晶粒尺寸分布逐渐均匀。
Based on the bottleneck problem of the new technology of axial rolling forming of ring billet, the evolution and reasonable control of as-cast billet structure were studied. For a ring rolling in both directions, the size of the slab will determine the degree of deformation and diameter, axial deformation distribution, and thus the final ring of the organization plays a vital role. In this paper, based on ABAQUS platform, a macro-micro coupled finite element model of 42CrMo steel was established. A blank size design method based on rolling ratio K and axial axial deformation ratio tanα was proposed. The same ring rolling process, the design of a variety of different K and tan α values of different sizes of multiple ring blank, simulating different cast 42CrMo billet size ring under the circumstance of the axial rolling process evolution. The results show that with the increase of K value, the dynamic recrystallization degree increases and the average grain size decreases and the distribution becomes more and more uniform. As the tanα value increases, the dynamic recrystallization of the upper and lower end faces increases, The grain size decreases and the average axial grain size distribution along the ring is gradually uneven. However, the dynamic recrystallization degree decreases in the inner and outer surface regions, the average grain size increases and the average radial grain size distribution along the ring gradually becomes uniform.