Abstract: Addressing the post-modification problem of the Baosteel Φ140 mm MPM plant,i.e.,rather low service life of the piercing plug that was in a material as originally designed by Meer GmbH,Germany,the plug material is changed with a new one,and improvements on the plug proper are carried out,involving the profile of and casting and oxidation processes for the plug.Thanks to relevant tests,effects by these corrective actions on the plug service span are analyzed.The operation result of the modified plug made of the new material shows that its service life is 7 times over that of the plug in Meer material,which leads to solution of the mill's big problem of unreasonably high plug consumption.