| 摘要 |
PURPOSE:To produce a low-alloy steel having a specified structure and excellent cold workability by a method wherein a low-alloy steel containing C, Mn, Cr, Si, Mo and Al in specified ratios is rolled and cooled in specified conditions. CONSTITUTION:A low-alloy steel containing 0.10-040% of C, 0.3-1.2% of Mn, 0.3-1.2% of Cr, 0.15-0.60% of Si, up to 0.17% of Mo and up to 0.10% of A , the balance being Fe and unavoidable impurities, is soaked at 900-1,050 deg.C and is hot rolled, followed by finish rolling at 680-900 deg.C. Then, the steel is cooled at a cooling rate of 0.03-1.5 deg.C/sec. Accordingly, a low-alloy steel having a two- phase structure consisting of fine ferrite and pearlite with a lamellar spacing of not larger than 150mum and excellent workability in cold drawing and cold extrusion is obtained. |
