A manufacturing method of a seamless metal pipe includes determining whether a preceding-stage stand group is used in outer diameter reduction or in thickness reduction of a hollow shell; and performing elongating on the hollow shell, into which a mandrel bar is inserted, based on the determination. In addition, in the elongating, when the preceding-stage stand group is used in the outer diameter reduction, the hollow shell is rolled in a state where an inner surface of the hollow shell does not come into contact with the mandrel bar in the preceding-stage stand group, and the hollow shell is rolled in a state where the inner surface of the hollow shell comes into contact with the mandrel bar in the succeeding-stage stand group.

A device for handling mandrel rods in a rolling plant for rolling seamless tubes comprises an inserter. The inserter moves a mandrel rod in a rolling direction such that the mandrel rod, starting from an initial state, is pushed into a tube blank situated upstream of the mandrel rod. A retaining device has a fixing unit that is movable along the rolling line and is designed to temporarily hold the mandrel rod at an action point at a rear end of the mandrel rod and to carry out a working stroke. The mandrel rod can be inserted into the rolling mill in the rolling direction and pulled out of the rolling mill counter to the rolling direction by the retaining device. The retaining device is designed such that the starting position of the fixing unit lies between the two ends of the mandrel rod in the initial state.

A device for handling mandrel rods in a rolling plant for rolling seamless tubes comprises an inserter. The inserter moves a mandrel rod in a rolling direction such that the mandrel rod, starting from an initial state, is pushed into a tube blank situated upstream of the mandrel rod. A retaining device has a fixing unit that is movable along the rolling line and is designed to temporarily hold the mandrel rod at an action point at a rear end of the mandrel rod and to carry out a working stroke. The mandrel rod can be inserted into the rolling mill in the rolling direction and pulled out of the rolling mill counter to the rolling direction by the retaining device. The retaining device is designed such that the starting position of the fixing unit lies between the two ends of the mandrel rod in the initial state.

A system that has a movable unit and an activating unit. The movable unit is equipped with at least one actuating element, which can be actuated using an actuator that is arranged on the movable unit. The activating unit includes an actuating mechanism for actuating the actuator for the actuating element. In order to simplify, reduce the cost of and make more flexible the energy supply to the actuator for adjusting the actuating element on the movable unit, the activating unit is installed in a stationary manner relative to the movable unit. At least one traction element is provided for transmitting the movement energy of the actuating mechanism to the actuator on the movable unit in the form of a traction force for adjusting the actuating element.