STEEL FOR MANUFACTURE OF PART BY COLD PLASTIC DEFORMATION AND METHOD OF MANUFACTURE OF SUCH PART Russian patent published in 2003 - IPC

FIELD: metallurgy; manufacture of parts by cold deformation, for example by cold forging, stamping or drawing without preliminary spheroidizing or softening treatment. SUBSTANCE: proposed steel has the following composition, mass- %: carbon, 0.03-0.16; manganese, 0.5-2; silicon, 0.05-0.5; chromium, up to 1.8; molybdenum, up to 0.25; aluminum, 0.001-0.05; titanium, 0.001-0.05; vanadium, up to 0.15; boron, 0.0005-0.005; nitrogen, 0.004- 0.012; sulfur, 0.001-0.09. If necessary, steel may additionally contain, mass-%: calcium, up to0/005; tellurium, up to 0.01; selenium, up to 0.04; lead, up to 0.3, the remainder being iron and admixtures stipulated by melting process. Composition of steel satisfies the following relationship: Mn+0,9Cr+1,3Mo+1,6V>2,2% and A1+Ti>3,5%N. Method proposed for manufacture of part from such steel includes obtaining semi-finished item, heating it to temperature of 940 C, hot rolling at final temperature of 900 to 1050 C and hardening for obtaining bainite structure. Then, cold plastic deformation is performed Strength of such part is higher than 1200 Mpa. EFFECT: enhanced efficiency and reliability; improved mechanical characteristics. 11 cl, 5 tbl, 2 ex