| 摘要 |
FIELD: metallurgy, in particular, production of high-strength fastening parts of specifically compound shape. ^ SUBSTANCE: method involves melting steel in electric furnace, said steel containing, wt%: carbon 0.27-0.32; manganese 0.30-0.65; silicon 0.01-0.17; sulfur 0.005-0.020; chromium 0.01-0.25; niobium 0.005-0.02; calcium 0.001-0.010; iron the balance, with ratios of 12/C-Mn/0.03>=20; Ca/S2>=.0650 being met; providing processing beyond furnace and continuous pouring of steel while protecting metal flow with argon; providing hot rolling of continuous bar at hot rolling initial temperature of 900-9500C and hot rolling final temperature of 740-8500C at deformation extent of at least 20% in final passes; providing cold gauging deformation at deformation extent of 20-25% and spheroidizing annealing including high-speed inductive heating in intercritical temperature range of cold deformed metal, with following controlled cooling within temperature range of 650-7300C at cooling rate of 0.5-1.00C/min and further cooling in thermal chamber at temperature of 100-2000C. Microalloying of steel with niobium inhibits recrystallization process at temperature of 1,000-1,1000C and provides for fine-grained structure of austenite favorable for steel spheroidization process. ^ EFFECT: provision for producing of rolled bars having structure enabling advantageous conditions for cold bulk pressing of compound shape fastening parts and improved workability characteristics of steel. ^ 3 cl, 1 ex |
