METHOD OF PRODUCTION STRIPS OUT OF LOW ALLOYED STEEL Russian patent published in 2009 - IPC C21D8/02 C22C38/46 

FIELD: metallurgy.

SUBSTANCE: at production of strips on continuous broad-strip mill for spiral seam electric welded tubes for transporting oil pipelines there is performed heating of slabs out of steel possessing following ratio of components, wt %: 0.11-0.14 C; 1.30-1.65 Mn; 0.4-0.6 Si; 0.02-0.05 Al; 0.01- 0.04 Nb; 0.01-0.03 Ti; 0.001-0.005 Ca; not more 0.01 V; not more 0.2 Cr; not more 0.2 Ni; not more 0.2 Cu; not more 0.015 P; not more 0.006 S; not more 0.010 N, Fe - the rest, its rough rolling to intermediate thickness, continuous finish rolling with temperature of beginning of rolling not more, than 970°C and temperature of end of rolling of 800-855°C, and cooling with water to the temperature of 540-580°C. In addition, total contents of C, Mn, Cr, Cu, Si, Ni and V in steel meet the ratio: C+(Mn+Cr+Cu)/20+Si/30+Ni/60+V/10≤0.24%, while finishing rolling of strips is carried out with total relative thickness reducing not less, than 64%.

EFFECT: upgraded impact resistance at negative temperature and fracture resistance of strips.

2 cl, 3 tbl, 1 ex