METHOD OF LENGTHWISE CONTINUOUS ROLLING OF SEAMLESS TUBES Russian patent published in 1997 - IPC

FIELD: rolled stock production. SUBSTANCE: method of lengthwise rolling of seamless tubes is realized by continuous process with use of mandrel in multistand rolling line. Rolls of successively arranged stands are mounted with mutual inclination. At first of two successive passes along bottom of roll grooves tube wall is thinned according to its thickness. At second pass zone of lateral surfaces of first pass is reduced along roll groove bottom until thickness of wall of ready tube; between rolling passes applying to tube controlled tension effort in order to decrease grown perimeter of tube caused by expansion by means of axially drawing tube without thinning its walls. EFFECT: high elongation degree at minimum number of stands providing production of doubled length tube. 2 cl, 3 dwg