| 摘要 |
PURPOSE:To obtain a steel tube having a good surface quality by setting temperatures of the inner and outer surfaces of a tube stock at a specified temperature in rolling a steel tube where specified values of C, Si, Mn, Cr, Ni, Mo, A, P, S, N, Ca, O are contained and the balance is made of iron, regulating the rolled strain epsilon at a specified value and rolling the steel pipe. CONSTITUTION:The high alloy seamless steel tube where C 0.03%, Si 0.50%, Mn 0.50%, Cr 20-25%, Ni;20-40%, Mo;2.5-4.5%, A 0.07%, P 0.02%, S 0.0020%, N 0.03%, Ca 0.0060%, O 0.0050% are contained and the balance is composed of iron and inevitable impurities is rolled. After piercing the temperatures of the inner and outer surfaces of the shell (tube stock) are made 1100 deg.C on the inner surface, 950 deg.C on the outer surface before the drawing and the rolled strain epsilon indicated by the formula is regulated to <=1.1 to be rolled. In this way, the austenitic high alloy seamless steel tube excellent in sourness resisting properties can be manufactured by rolling method and the steel tube free from cracks and excellent in surface quality can be obtained. |
