| 摘要 |
<p>PURPOSE:To uniformize temp. distribution on the peripheral surface of a blank pipe material by forming a pierced hollow blank pipe into a cylindrical shape by the mandrel mill, etc., then, by injecting highly pressurized water in reduced flow rate on the upper part of the blank pipe to descale the whole peripheral surface. CONSTITUTION:The pierced hollow blank pipe 1 is formed into the cylindrical shape by the mandrel mill, etc., heated to about 950 deg.C by a reheating furnace, then, descaled by the descaler 2 to convey in the direction shown by the arrow 3 in the figure, and fed to the latter working machine such as stretch reducer, etc. At this time, the descaler 2 is composed of the normal injection ring 5 injecting the pressurized water 4a in the conveying direction 3 and reversal injection ring 6 injecting the pressurized water 4b in the reversal direction against the conveying direction 3, the highly pressurized water 4a, 4b pressurized about 190kgf/cm<2> is injected on the upper part of the blank pipe 1 with the reduced flow rate. By this method, the temp. distribution of the peripheral surface of the blank pipe after descaling is equalized and the thickness deflection on the pipe material rolled in the latter stage is not generated.</p> |
