【摘要】 拉伸翻管精密成形易于实现双层管零件精确、高效、灵活的制造而具有广阔的应用前景,然而拉伸翻管精密成形过程的成功实施受到变形区失稳破裂的制约,而成形力与其密切相关。因此,采用有限元数值模拟对拉伸翻管精密成形过程中成形条件参数对成形力的影响规律进行了研究,结果表明,当芯棒圆角半径大于某一值时,在整个成形过程中管坯形状基本保持不变,从而较好地实现了精确成形;对于给定的芯棒圆角半径与管坯外径之比r/d0或管坯壁厚与外径之比δ0/d0,r/δ0对成形力影响很大。并且存在着一个临界参数k,当r/δ0<k时,翻管稳态成形力F随着 r/δ0值的增大而减小;当r/δ0=k时,F取最小值;当r/δ0>k时,F随着r/δ0值的增大而增大;硬化指数对成形力影响较大,硬化指数越小成形力越大,摩擦因数对成形力的影响则相对较小,而接触面良好的润滑有助于改善成形件的表面质量。更多还原

【Abstract】 TIAD (Tube inversion by the axial drawing) is an advanced forming process for manufacturing double-walled tubes with high quality, high efficiency, low consumption. However, whether to realize forming process depends on whether to produce the tearing in deforming zone, which has a close relationship with deforming force. Therefore, it is important to study the influence of forming condition parameters on the deforming force by FEM numerical simulation for the realization and the development of TIAD precision forming process. The results obtained show: (1) During the whole forming process, the shape of the tube keeps unchanged, so the precision forming can be easily realized; (2) For a given r/d0 or δ0/d0, the deforming force depends mainly on the value of r<δ0, and there is a critical parameter k, when r/δ0<k, the steady forming force decreases with the increase of r<δ0; on the contrary, when r/δ0>k, the steady forming force increases with the increase of r/δ0; (3) The material hardening exponent n of the tube has a remarkable influence on the deforming force. The smaller the value of n, the larger the forming force. The influence of friction coefficient on the deforming force is relatively small, however, good frictional condition will help to improve the surface quality of the part gained.更多还原