LOW-CARBON STRUCTURAL STEEL WITH IMPROVED MACHINABILITY

摘要

FIELD: metallurgy.;SUBSTANCE: steel features the following chemical composition, in wt %: carbon - 0.18-0.23, silicon - 0.17-0.37, manganese - 0.70-1.10, chromium - 0.40-0.70, nickel - 0.40-0.70, molybdenum - 0.15-0.25, tin - 0.05-0.30, iron and impurities making the rest. Steel contains following substances as impurities, in wt %: sulfur - not over 0.025, phosphorus - not over 0.025, copper - not over 2.20. Total content of sulfur and tin does not exceed 0.31 wt %, while molybdenum-to-copper ratio varies from 0.8 to 4.8.;EFFECT: better machinability, higher efficiency of hot forming, sufficient mechanical properties.;4 cl, 2 tbl, 14 ex