Abstract: There exist certain problems during the hot-piercing operation for the T91 pipe,including high plug consumption,and occurrence of inner fold and end-outer surface crack of the shell,etc. Accordingly,proper heating parameters and piercing adjustment parameters are determined,while relevant operational tools and dies are modified. As a result,the above mentioned problems concerning high plug consumption and obvious inconsistency of both outer and inner surface quality of the shell are solved,which leads to such a efficiency that the productivity of each individual plug is up to 125 pieces per hour,and the average productivity is about 400 pieces,resulting in considerable enhancement of both the shift output and the cost effectiveness.