| 摘要 |
FIELD: metallurgy, namely blanks of construction steel suitable for welding and processes for making them. ^ SUBSTANCE: blank contains, mass %: 0.10< C <0.22; 0.50 <Si <1.50; Al < 0.9; 0 < Mn <3.0; 0 < Ni < 5.0; 0 < Cr < 4.0; 0 < Cu < 1.0; 0 < Mo + W/2 <1.5; 0.0005 < B < 0.010; N < 0.025; if necessary at least one element selected from group containing V, Nb, Ta, S, Ca in quantity less than 0.3 and(or) Ti and Zr in quantity equal to or less than 0.5; iron and impurities formed at steel melting, the balance while content values of aluminum, boron, titanium and nitrogen calculated in thousandth of % of said composition are restricted in addition. Steel structure may be bainite, martensite or martensite-bainite and it may include in addition 3 - 30 vol.% of remaining austenite. Method for making such blank comprises steps of austenization of blank by heating it till temperature in range from Ac3 till 1000°C, preferably from Ac3 till 950°C; cooling it till temperature equal to or less than 200°C in such a way that to provide in core of blank cooling rate from 800°C till 500°C equal to or exceeding critical bainite rate; if necessary tempering blank at temperature equal to or less than Ac1. ^ EFFECT: improved hardening ability of steel without lowering its welding capability. ^ 11 cl, 2 tbl |
