TWO-PHASE STEEL SHEET AND METHOD OF MAKING THEREOF Russian patent published in 2016 - IPC C21D8/02 C22C38/14 C23C2/06 C22C38/58 

FIELD: metallurgy.

SUBSTANCE: sheet is produced from two-phase steel containing wt%. %, C 0.01-0.1, Mn 0.2-3, Al 0.04-1.5, Ti 0.015-0.2, P 0.01 or less, S 0.005 or less, N 0.01 or less, if the following condition is fulfilled [Ti] - 48/14 × [N] - 48/32 × [S] ≥ 0 %, and it has been established that Ex.C (%) = [C] - 12/48 × {[Ti]+48/93 × [Nb] - 48/14 × [N] - 48/32 × [S]}, following condition is satisfied 0.001 ≤ Ex.C (%)/fsd (%) ≤ 0.01, Fe and the rest - impurities, wherein at the depth of 1/4 of the plate thickness the microstructure is two-phase, with its main phase consisting of polygonal ferrite dispersion strengthened with carbide Ti, and the second phase including multiply dispersed products of low-temperature conversion at the area ratio of 1-10 % (fsd (%)), and the average diameter of crystals of products of low-temperature conversion is 3-15 mcm, and the average value of maximum distance between the products of low-temperature conversion is 10-20 mcm.

EFFECT: higher ductility and strength with provision of uniform relative elongation and suitability for hole flanging.

12 cl, 5 tbl, 1 dwg