Development of Process of Rolling Light-wall Seamless Tube with Φ273 mm Assel Pipe Mill

In case of rolling light-wall seamless steel tubes with D/S ≥25 with the Assel mill, several problems are apt to be encountered with, including forming of bell-like end of the shell, strenuously swinging of the shell during rolling, and developing of defective inner surface spiral mark and so on, which greatly impede fully tapping of the operation line’ s production capacity. Accordingly, a series of technical modification actions are taken by Hubei Xinyegang Steel Co., Ltd., including adding a guiding device to the run-out table and relevant measuring units to the incoming section, improving the roll profile of the mill and optimizing the rolling process parameters, etc. As a result, failures as occurring in the rolling operation like material twisting or jamming are considerably reduced, and the severity of the said inner surface spiral mark is so lessened, while the tube wall thickness tolerance is tightened up to ±8%, and the mill yield increased to over 90%.