| 摘要 |
PURPOSE:To produce a titled boiler tube by hot extruding a stainless steel billet contg. specific contents of C, Si, Mn, Ni, Cr, Nb in a specific temp. range to produce a blank pipe, cold working the same at a reduction ratio higher than specific values and applying heat treatments of heating and quenching thereto in a specific temp. range. CONSTITUTION:A stainless steel billet is composed, by wt%, of 0.06-0.09 C, 0.3-0.9 Si, 0.5-2 Mn, 9-13 Ni, 17-20 Cr, 8XC%+0.03-1 Nb, containing 0.04- 0.08 N according to need, and the balance Fe and impurities. Such stainless steel billet is hot extruded to a blank pipe in a 1,100-1,300 deg.C temp. range and after the blank pipe is cold worked at >=10% reduction ratio, the pipe is heat- treated at 1,120-1,250 deg.C and quenched. In some cases, heat treatments of 1,120- 1,300 deg.C are applied prior to cold working. |
