Abstract: Addressing the problems related to the piercing process of T91 steel Φ110 mm billets such as high consumption of plugs,loosing or breaking of plug connections,as well as the inner folds on pierced products,some countermeasures are proposed.It is indicated that by establishing a reasonable heating schedule,improving the structure of the molybdenum based plugs and connections,and standardizing the operation of the plugs,a stable piercing process with significantly lowerd cost can be realized when each plug may averagely pierce 363 billets in total and 67 billets per hour.