PURPOSE: To lower the generation rate of pit flaws without increasing lap flaws by bringing a wire brush into contact with the whole surface n the circumferential direction of the outer peripheral surface while jetting high pressure water on the outer peripheral surface of a rolled stock carried in the axial direction.
CONSTITUTION: A high pressure water injection header 3 is provided so that high pressure water can be jetted on the whole surface in the circumferential direction of the outer peripheral surface of a rolled blank 2 for seamless steel tube carried on carrier rollers 1 in an axial direction. The wire brushes 4a, 4b are provided on the front and rear surface of the injection header 3 so that they come into contact with the whole surface in the circumferential direction of the outer peripheral surface of the rolled stock 2 for seamless steel tube. When the scale generated on the rolled stock 2 is descaled first, the scale is removed by wire brush 4a, then, high pressure water is ejected from the injection header 3 to crush the scale finely and the final scale is scraped off with the wire brush 4b.
YASUOKA HIDENORI
KAJIYAMA FUYUHIKO
