| 摘要 |
A high strength, high toughness steel alloy is disclosed. The alloy has the following weight percent composition. Element C 0.30-0.55 Mn 0.6-1.75 Si 0.9-2.8 Cr 0.6-2.5 Ni 2.70-7.0 Mo + � W 0.25-1.3 Cu 0.30-1.25 Co 0.01 max. V + (5/9) � Nb 0.10-1.0 Ti 0.01 max. Al 0.015 max. Ca 0.005 max. The alloy further includes a grain refining element selected from the group consisting of 0.0001-0.01% Mg, 0.001-0.025% Y, and a combination thereof. The balance of the alloy is iron and usual impurities. Also disclosed is a hardened and tempered steel article having very high strength and fracture toughness and formed from the alloy set forth above. The alloy article according to this aspect of the invention is further characterized by being tempered at a temperature of about 500� F. to 600� F. |
