图1为发动机进气接管,是用10号钢φ80×1.5mm薄壁无缝钢管经过扩口成形的零件。由图中可知,其口部胀形率达21％,并有较长的变形区域,属于大变形的扩口成形。为防止与发动机安装时漏气,成形后的零件要求有较高的表面光洁度,φ93_0~(0.1)mm Figure 1 for the intake manifold engine, is the No. 10 steel φ80 × 1.5mm thin-walled seamless steel pipe through the flared parts. As can be seen from the figure, the mouth bulge rate of 21%, and has a longer deformation zone, is a large deformation of the flaring shape. To prevent air leakage during engine installation, the formed parts require a high surface finish, φ93_0 ~ (0.1) mm