Yield strength 1100MPa level engineering machinery non-quenched and tempered hot rolled strip and preparation method thereof

[0023] Example 1

[0024] The molten steel is smelted in a 150-ton converter according to the set composition and continuously cast into a slab. The set composition is C 0.06% by weight, Si 0.20%, Mn 1.60%, Nb 0.02%, V 0.04%, Ti 0.15% , Ni 0.4%, Mo 0.20%, P<0.012%, S<0.01%, the balance is iron Fe, the thickness of the cast slab is 220mm.

[0025] The cast slab is heated to 1250°C for rough rolling. The rough rolling process is 5 passes, the roughing start-rolling temperature is 1170°C, the roughing final rolling temperature is 1070°C, and an intermediate slab with a thickness of 38mm is obtained.

[0026] The intermediate billet is finished rolling, the finishing rolling process is 7 passes, the finishing rolling temperature is 980℃, the second rolling temperature is 950℃, the third rolling temperature is 930℃, the fourth rolling temperature is 890℃, and the fifth rolling temperature is 850℃. ℃, the six-rolling temperature is 820℃, the final rolling temperature is 800℃, the reduction o

[0028] Example 2

[0029] The preparation method and composition of the cast slab are the same as in Example 1, and the thickness of the cast slab is 250 mm.

[0030] The rough rolling process was the same as in Example 1, and an intermediate billet with a thickness of 58 mm was obtained.

[0031] The intermediate billet is finished rolling. The finishing rolling process is 6 passes. The finishing rolling temperature is 950°C, the second rolling temperature is 930°C, the third rolling temperature is 910°C, the fourth rolling temperature is 880°C, and the fifth rolling temperature is 850°C. ℃, the final rolling temperature is 830℃, the reduction of each pass of finishing rolling is controlled at 15-40%, and the thickness of the strip after finishing rolling is 6mm.

[0032] After finishing rolling, it is water-cooled to 400°C at a speed of 35°C / s, and then coiled by a coiler. The composition obtained by weight percentage is C 0.06%, Si 0.20%, Mn 1.60%, Nb 0.02%, V 0.04%, Ti 0.15 %, Ni

[0033] Example 3

[0034] The preparation method and composition of the cast slab are the same as in Example 1, and the thickness of the cast slab is 240 mm.

[0035] The rough rolling process was the same as in Example 1, and an intermediate billet with a thickness of 45 mm was obtained.

[0036] The intermediate billet is finished rolling, the finishing rolling process is 5 passes, the finishing rolling temperature is 1020℃, the second rolling temperature is 980℃, the third rolling temperature is 920℃, the fourth rolling temperature is 900℃, and the final rolling temperature is 880 ℃, the reduction of each pass of finishing rolling is controlled at 15-40%, and the thickness of the strip after finishing rolling is 4mm.

[0037] After finishing rolling, it is water-cooled to 200°C at a speed of 15°C / s, and then coiled by a coiler. The composition obtained by weight percentage is C 0.06%, Si 0.20%, Mn 1.60%, Nb 0.02%, V 0.04%, Ti 0.15 %, Ni 0.4%, Mo 0.20%, P<0.012%, S<0.01%, the balanc