LOW-ALLOY STEEL AND ARTICLE MADE FROM THIS STEEL Russian patent published in 2003 - IPC

FIELD: ferrous metallurgy; low-alloy steels and articles made from such steels; production of steel sheets for heavy-loaded parts of automobiles and agricultural machines by punching and cold stamping. SUBSTANCE: proposed low-alloy steel contains the following components, mass-%: carbon, 0.0-0.09; manganese, 0.25-0.40; silicon, 0.01-0.10; copper, 0.01-0.50; aluminum, 0.02-0.07; phosphorus, 0.07- 0.12; calcium, 0.0005-0.0010; boron, 0.0008-0.005; nitrogen, 0.003- 0.007; sulfur, 0.005-0.025; the remainder being iron; content of phosphorus is related to content of carbon and manganese and content of sulfur is related to manganese at the following dependences: P/[0,198-0,26(C+Mn)]>0,6 and S/Mn<6•10^-2./ Articles from such steel may be made in form of hot-rolled strip, 2.0-15.0 mm thick and in form of cold-rolled sheet or band, 0.5-3.0 mm thick. EFFECT: enhanced static and fatigue strength at retained stampability. 4 cl, 2 tbl, 1 ex