MANUFACTURING METHOD OF COLD STRIP FROM BIPHASE STEEL WITH FERRITE-MARTENSITE STRUCTURE AND RECEIVED STRIP Russian patent published in 2008 - IPC C21D8/04 C22C38/04 C21D9/46 

FIELD: metallurgy.

SUBSTANCE: they receive slab from steel, containing, wt %: 0.010≤C≤0.100, 0.050≤Mn≤1.0, 0.010≤Cr≤1.0, 0.010≤Si≤0.50, 0.001≤P≤0.20, 0.010≤Al≤0.10, N≤0.010, at that the rest is iron and admixtures, forming at receiving of during steel receiving. In the sequel there are implemented following stages: hot slabbing to strip, rolling of received strip in a hot condition at temperature, which is in limits from 550 till 850°C, cold rolling with draft ratio, which is in limits from 60 till 90%, continuous annealing in intercritical temperature range, cooling till ambient temperature at one or several stages, at that velocity of cooling from 600°C till ambient temperature is from 100°C/s till 1500°C/s; in case of need it is implemented strip abatement at temperature lower then 300°C. At that annealing and cooling processes are implemented so that as the final result strip contains from 1 till 15% of martensite.

EFFECT: increasing of strip formability and mechanical properties.

22 cl, 2 tbl, 2 dwg, 1 ex