METHOD OF PRODUCTION OF STRIPS OUT OF LOW ALLOYED STEEL Russian patent published in 2009 - IPC C21D8/02 C22C38/22 C22C38/42 

FIELD: metallurgy.

SUBSTANCE: invention can be implemented for production of strips with hardness grade of X80; said strips are used at construction of oil and gas pipelines. Slabs are heated to temperature of austenisation, further rough and finish multi-pass rolling is performed and strips are cooled with water; also finish rolling is carried out with total relative reducing not less, than 50%; temperature of end of rolling is maintained equal to 700-880°C, while cooling strips with water is performed at rate not less, than 10°C/sec to temperature not exceeding 580°C. In addition, low alloyed steel has the following chemical composition, wt %: 0.05-0.10 C; 0.20-0.40 Si; 1.50-1.90 Mn; 0.15-0.40 Mo; 0.02-0.06 Nb; 0.01-0.03 Ti; not more 0.01 B; not more 0.05 Al; not more 0.30 Cr; not more 0.50 Ni; not more 0.30 Cu; not more 0.010 P; not more 0.004 S; Fe - the rest.

EFFECT: upgraded hardness, plasticity and impact resilience of strips.

2 cl, 3 tbl