| 摘要 |
PURPOSE:To obtain the title steel with high strength and good shelf energy by adding Cr to a common steel component system, followed by working in the Ar3- Ar1 transformation region and air cooling or heat treatment at a temp. below Ar1 under limited conditions. CONSTITUTION:Steel consisting of C; 0.05-0.25%, Si<=0.7%, Mn; 0.5-0.8%, Cr; 0.01-1.2%, Mn+(6/5)Cr<=2%, and the balance iron and inevitable impurities is heated to a temp. above 1,000 deg.C-1,300 deg.C, worked by more than 10% in the Ar3 region, and air cooled or heat treated at a temp. below Ar1 for more than 30min. Thus, although vTrs lowers as the strength increases, vEshelf does not lower, and hence an increase in strength becomes possible while keeping good vTrs and vEshelf. Accordingly, a high strength steel material can be obtd. having good crack forming and stopping characteristics to rupture. In addn., carbon equivalent can be reduced intech same strength and weldability is also improved. |
