Research on Performance Characteristic of Novel Fomichev Plug Used in Julong-Type Piercer

The novel Fomichev plug described in this paper is of characteristic producing equal unit-reduction of wall thickness along its perforation section during seamless tube piercing, which designed on the base of the roll opening of Julong piercer, taking into account for both feed angle and toe angle of a cone type piercer. Then a 3-D thermal-mechanical coupled numerical simulation on performance characteristic of novel Fomichev plug is presented with the aid of commercial FE code MSC.SuperForm, according to practical process parameters of piercing and rolling for steel grade P91 on Julong piercer in Yangzhou Chengde Steel Pipe Co., Ltd. By comparison with conventional plugs, as FE simulation result shows that the new plug reduces the damage value of the workpiece, thus decreases the tendency of lamination defects. What’s more, the axial resistance of novel Fomichev plug is smaller than the conventional, which is in favor of biting condition and increases piercing efficiency. Furthermore, the newly-designed plug’s temperature field is more uniform, which can alleviate failure of piercing plug caused by overtop local temperature, prolong its working life, and improve the quality of hollow shells.