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由于钛合金对应变速率十分敏感,因此轧辊运动对钛合金大环热辗扩成形过程有重要作用。提出了相对速率vr的概念来表征轧辊运动参数的综合作用,涉及的运动参数包括驱动辊旋转速率n1和芯辊进给速率v,并且基于稳定成形条件采用解析方法确定了vr的合理取值范围。其次,运用动力显式有限元程序ABAQUS/Explicit 建立了可靠的钛合金大环热辗扩成形过程的热力耦合三维有限元模型。最后,采用有限云模拟方法,探究了vr对该成形过程的影响效应及其机制。结果表明;尽管通过减小n1来增大vr与通过增大v来增大vr 均使每转进给量△ hi 增大,但它们对成形过程的影响效应并非完全一致,比如对非均匀应变分布的影响;较大的vr有助于提高成形环件的端面质量和应变与温度分布的均匀性,但对成形力有不利影响。
Due to the sensitivity of titanium alloy to strain rate, the roll motion plays an important role in the hot ring rolling process of titanium alloy. The concept of relative velocity vr is proposed to characterize the comprehensive effect of roll motion parameters. The involved motion parameters include the rotational speed n1 of the driving roller and the feed rate of the core roller v, and the analytic method is used to determine the reasonable range of vr based on the steady forming conditions . Secondly, a three-dimensional finite element model of thermodynamic coupling was established by using dynamic explicit finite element program ABAQUS / Explicit. Finally, the effect of vr on the forming process and its mechanism are explored by using finite cloud simulation method. The results showed that although the increase of vr by decreasing n1 and the increase of vr by increasing v increased the amount of feed Δ hi per revolution, their effect on the forming process was not exactly the same. For example, for non-uniform strain The larger the vr helps to improve the quality of the end face of the forming ring and the uniformity of the strain and temperature distribution but has an adverse effect on the forming force.