| 摘要 |
FIELD: metallurgy, namely rolled stock production, possibly manufacture of steps in wide strip rolling mills for electrically welded straight-seam casing tubes designed for oil and gas wells. ^ SUBSTANCE: method comprises steps of heating slabs; rough rolling of them till intermediate thickness; finish rolling in temperature range no more than 970°C till temperature 820 - 880°C; cooling slabs with water till coiling temperature. Slab contains next ingredients, mass%: carbon, 0.16 - 0.22; silicon, 0.1 - 0.3; manganese, 1.0 - 1.4; chrome, 0.1 - 0.3; vanadium, 0.07 - 0.12; titanium, 0.01 - 0.025; niobium, 0.01 -0.04; aluminum, 0.02 - 0.05, nickel, no more than 0.3; copper, no more than 0.1; sulfur, no more than 0.008; phosphorus, no more than 0.15; iron, the balance while Nb + V + Ti < 0.15. Temperature of coiling is determined according to thickness of strip, namely: 500 - 580°C, 520 - 590°C, 530 - 600°C for strips with thickness values 10.0 mm, 9.1 - 10.0 mm and 6.0 - 9.0 mm respectively. ^ EFFECT: improved mechanical properties, less loss of yield, elimination of additional heat treatment of strips. ^ 3 cl, 3 tbl, 1 ex |
