Thermal expanding medium frequency pipe expanding machine adopts the pipe with strong shrinkage for expanding diameter. Seamless steel pipe is one kind of thermal expanding pipe. An expanding process in which the diameter of a tube is enlarged by means of intermediate frequency induction at high temperature. In a relatively short period of time to thicken the steel tube, intermediate frequency tube expanding machine itself is a non-standard product, according to customer requirements to develop a special type of seamless tube, and labor cost, raw material tube blank cost is relatively low, high production efficiency, is the current international and domestic development trend of tube expander hydraulic field. Intermediate frequency tube expander integrates hydraulic technology and intermediate frequency induction heating technology. In the production of seamless steel tube diameter become large diameter steel tube, because the production capacity of intermediate frequency tube expanding machine can not process too large diameter pipe, we need to first process small diameter pipe and then use thermal expansion method in the processing of the production of seamless steel tube.