PRODUCTION FOR SPIRAL STEEL PIPES WITH ROUGH SURFACE STEEL PLATES HAVING BEEN ROLLED WITH ELECTRIC DISCHARGE MACHINING ROLL

摘要

PURPOSE:To produce steel pipes for composite piles of superior adhesiveness to concrete and mortar by rolling steel plates with a rolling roll which is formed with unulated patterns on the surface through electric discharge machining to roughen the surface thereof and producing steel pipes with the rough surface being faced on the inner side.