METHOD FOR MANUFACTURE OF SHEETS FROM LOW-ALLOY STEEL Russian patent published in 2002 - IPC

FIELD: manufacture of rolled products. SUBSTANCE: method involves heating low-alloy steel slabs for subsequent rolling; providing multiple pass hot rolling with subsequent heating, quenching and tempering (thermal improvement). Compression in finishing pass is set to be at least 15%, with temperature at final rolling stage being not in the excess of 950 C, and heating for rolling process is provided until temperature reaches 1,200-1,300 C. Initial sheet quenching temperature does not exceed 94 C and is at least 920 C. Tempering is conducted by heating sheets to temperature of 590-640 C at specific heat time of 1.05-2.1 min per millimeter of sheet thickness with following cooling at mean cooling rate of 1-4 C/s. Method is used for manufacture of high-strength weldable low-alloy sheet steel for metal constructions. EFFECT: increased toughness of sheets at negative temperatures, improved strength and stable mechanical characteristics. 3 cl, 3 tbl