| 摘要 |
1275096 Hot-worked steel INLAND STEEL CO 28 Aug 1969 [28 Aug 1968] 42859/69 Heading C7A A hot-worked steel article has a composition (wt per cent) of: C 0.02 -0.26 Mn 1.25 -1.75 Si 0.75 -1À5 N 0.003-0.015 Al 0.01 -0.08 V 0 -0.07 Nb 0 -0À03 W 0 -0À1 Fe and impurities - balance, and has a microstructure consisting of ferrite plus pearlite with a ferrite grain size no coarser than 9.5 ASTM, and a yield strength greater than 50, 000 p.s.i. The article (e.g. plate, tube or pipe-forming skelp) may be produced by hotworking, such as rolling, forging or extruding, including a finishing step in which the article undergoes a 25% reduction at a temperature above the A 1 point, followed by rapid cooling as by still air, H 2 O spray or air impingement. Normalizing may follow at a temperature above the A 3 point and up to 1, 750‹F. |
