| 摘要 |
PURPOSE:To provide high strength and toughness to an unrefined steel composition as rolled by hot working a steel contg. specified amounts of C, Si, Mn, Al, V, Nb and N and by subjecting it to controlled cooling. CONSTITUTION:A steel having a composition consisting of, by weight, 0.20-0.55% C, 0.10-1.00% Si, 0.50-2.50% Mn, 0.003-0.10% Al, 0.05-0.20% V, 0.01-0.10% Nb, 0.005-0.1% N and the balance essentially Fe or further contg. 0.003-0.20% rare earth elements is hot worked and cooled at 30-500 deg.C/min cooling rate. At this time, the hot working is finished in the austenite range or the austenite-ferrite two-phase range. A steel composition having high strength and toughness can be obtd. without adding expensive alloying elements in large quantities or requiring heat refining.
|
