HOT-STAMPED MICRO-ALLOYED STEEL WITH SUPER DESTRUCTION AT FRACTURE AND PROCESSABILITY Russian patent published in 2011 - IPC C22C38/60 

FIELD: metallurgy.

SUBSTANCE: steel contains, wt %: C from more, than 0.35 to 0.60, Si from 0.50 to 2.50, Mn from 0.20 to 2.00, P from 0.010 to 0.150, S from 0.040 to 0.150, V from 0.10 to 0.50, Zr from 0.0005 to 0.0050, Ca from 0.0005 to 0.0050 and N from 0.0020 to 0.0200, Al less, than 0.010, Fe and unavoidable impurities - the rest. Structure of steel contains bainite fraction at amount of 3% or less including 0 % and the rest corresponds to ferrite/pearlite. Amount of inclusion of MnS of width 1 mcm or more in the region located at distance of 1/4 diametre from centre of hot rolled steel is 10% or less including 0% of total amount of inclusions of MnS in structure of steel. Average ratio of width to thickness of inclusions of MnS amounts to 10 or less.

EFFECT: good processability and destruction at fracture without reduced efficiency and deterioration of mechanical properties.

3 cl, 1 dwg, 3 tbl, 1 ex