Nb-Ti-IF钢高速深冲多步拉深工艺研究

Study on multi-step drawing process of high speed deep drawing of Nb-Ti-IF steel

为研究Nb-Ti-IF钢深冲时各工序各部位壁厚减薄规律,通过数值模拟及微观组织观测对各工序各主要部位进行研究,建立了冲压模型,系统研究了深冲过程中的金属流动规律。结果表明,在各工序拉深过程中晶粒变形剧烈,尤其是在凸凹模圆角处。随着拉深工序的进行,晶粒逐渐从典型的铁素体晶粒变得细长,在最后两个拉深工序中晶粒拉伸更加明显。拉深过程中应力主要集中于凹模半模锥角以及定径带位置附近。筒壁最小厚度达到0.35 mm,并且筒壁厚度均匀。对模拟得到的每一工序的拉深成品件的特殊位置进行了厚度测量,在拉深高度方向上,从筒壁中下部到模角附近壁厚逐渐减小,底部也存在减薄情况,筒壁中下部减薄量最大,可达35%。

To study the laws of wall thickness thinning at each part of each process during the deep drawing of Nb-Ti-IF steel,the main parts of each process were studied based on the numerical simulation and the observation of microstructure,and the stamping model was established,and the metal flow laws during the deep drawing process were systematically studied.The results show that the grain deformation is severe during each drawing process,especially at the punch and concave die fillet.With the proceeding of the deep drawing process,the grain gradually changes from the typical ferrite grain to slender,and the grain drawing is more obvious in the last two deep drawing processes.During the deep drawing process,the stress is mainly concentrated near the half die cone angle and the location of the sizing band.The minimum thickness of the cylinder wall reaches 0.35 mm,and the thickness of the cylinder wall is uniform.The thickness of the special position of the finished drawing parts in each process obtained by simulation was measured.In the deep drawing height direction,the wall thickness decreases gradually from the middle and lower part of the cylinder wall to the die fillet,and there is also thinning at the bottom.The thinning at the middle and lower part of the cylinder wall is the largest,up to 35%.