| 摘要 |
FIELD: metallurgy; production of round merchant shapes made from alloyed steel for cold die forging of intricate-shape fasteners. ^ SUBSTANCE: merchant shapes are molten from alloyed steel containing the following constituents, mass-%: carbon, 0.36-0.45; manganese, 0.50-0.80; silicon, 0.01-0.37; chromium, 0.80-1.10; nickel, 0.001-0.10; copper, 0.001-0.10; molybdenum, 0.001-0.03; sulfur, 0.005-0.020; niobium, 0.005-0.02; calcium, 0.001-0.010; the remainder being iron and unavoidable admixtures at the following ratio: Cr/28+C/12>=0.060; Ca/S>=0.065; maximum number of steel impurity with non-metallic inclusions by sulfides, oxides, silicates and nitrides does not exceed 3 in each kind of inclusion; shapes have homogeneous spheroidized structure in length which contains no less than 80% of grain perlite at size of actual grain of 5-10; diameter of wire ranges from 10 to 30 mm; decarbonized layer does not exceed 1.5% of diameter; amount of cold heading is no less than 1/3 of height; tensile strength does not exceed 620 MPa; relative elongation is no less than 18% and relative reduction of area is no less than 55%. ^ EFFECT: rational conditions for performing cold die forging at enhanced characteristics of ductility, hardenability and low level of strain hardening. ^ 1 ex |
