| 摘要 |
PURPOSE:To roll the pipe with a good surface quality and without cracking by specifying the temp. condition before drawing and strain condition in drawing to a pipe stock after piercing when manufacturing the seamless steel pipe of a high alloy of which components are confined. CONSTITUTION:When rolling the seamless steel pipe of the high alloy contg., by weight, <=0.03% C, <=0.50% Si, <=0.50% Mn, 20-25% Cr, 20-40% Ni, 2.5-4.5% Mo, <=2.0% Cu, <=1.5% Ti, <=0.07% Al, <=0.02% P, <=0.0020% S, <=0.03% N, <=0.0060 % Ca and <= 0.0050% O and consisting of the balance Fe with impurities, the inside and outside temps. of the shell after piercing are taken as <=1050 deg.C on the inside surface and as >=950 deg.C on the outside surface before drawing and this pipe is rolled by controlling the rolling strain epsilon that is expressed by the formula to <=1.0. In the formula, t1 is the thickness (mm) of shell before drawing, t2 is the thickness (mm) of shell after drawing, I1 is the length (mm) of shell before drawing and I2 is the length (mm) of shell after drawing. |
