Method for producing a seamless steel pipe and rolling mill for performing the method

Abstract

The invention relates to a method and a rolling mill for producing a seamless steel pipe in a continuous rolling process, where semi-finished material is first formed into a hollow block (8) in a rotary rolling mill, said block then being rolled in a multi-tooled continuous rolling mill (1) over a previously inserted mandrel (10) to form a tube blank (9), wherein the mandrel (10) receiving the hollow block and held by a mandrel holding and transporting device (5) disposed on the entry side is fed into the continuous rolling mill (1) and is transported back to the entry side after the tube blank has been rolled off of the mandrel (10) on an extracting rolling mill (4) connected downstream of the continuous rolling mill. An aim of the invention is to allow high production rates at the same product quality, particularly at a low drop in the temperature of the tube blanks. The aim is achieved in that the mandrel (10) with the tube blank (9) is released by the entry-side mandrel holding and transporting device (5) after exiting the last tool (2.n) of the continuous rolling mill (1) and thus is transferred to an accompanying second mandrel holding and transporting device (6) connected downstream and held by the same until the tube blank (9) is rolled off by means of the extracting rolling mill (4).

Description

technical field [0001] The invention relates to a method for the production of seamless steel tubes in a continuous rolling process, in which the billet is first formed into a hollow billet in a piercing mill, and then in a multi-stand continuous rolling mill on a previously pierced mandrel The hollow billet is rolled into a hollow billet, wherein the mandrel carrying the hollow billet and held by the mandrel holding and conveying device arranged on the inlet side is conveyed to the continuous rolling mill, when the hollow billet is connected to the continuous rolling mill The mandrels are conveyed back to the entry side after having been detached from the mandrels on the stripper following the rolling mill. The invention also relates to a rolling mill for carrying out the method. Background technique [0002] This method and rolling mill for the manufacture of seamless steel pipes in a continuous rolling process (continuous pipe rolling process) by means of a continuous ro...

AI Technical Summary

Problems solved by technology

For both cases and known as free-floating (freely following the moving mandrel) or semi-floating (holding while rolling and then following the moving mandrel) and restraint (holding while rolling and then following the moving mandrel) The process of withdrawing the mandrel) can either make the output of the rolled piece large, sometimes accompanied by a short mandrel length (semi-floating), but the capillary temperature is not uniform, so that the hollow tube blank needs to be adjusted during subsequent processing Reheating, either can make the capillary temperature uniform, but the cycle time is longer due to the mandrel being transported back to the rolling line, which in turn leads to less rolling stock output

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