High-strength low-alloy steel

Claim 1

A METHOD OF MAKING A HIGH STRENGTH LOW ALLOY STEEL STRIP HAVING A MINIMUM YIELD STRENGTH OF 50,000 PSI AND GOOD FORMABILITY PROPERITIES WHICH COMPRISES SUBJECTING A SLAB OF STEEL HAVING A COMPOSITION CONSISTING ESSENTIALLY OF, BY WEIGHT, 0.10 PERCENT MAXIMUM CARBON, 0.30 TO 0.80 PERCENT MANGANESE 0.02 PERCENT MAXIMUM SULPHUR, 0.06 PERCENT ALUMINUM, 0.01 TO 0L02 COLUMBIUM, 0.06 PERCENT MAXIMUM CERIUM, THE BALANCE BEING IRON AND INCIDENTAL IMPURITIES, TO A HOT-ROLLED FINISHING TEMPERATURE IN THE RANGE OF 1620* T0 1670*F AND COLLECTING THE STRIP IN A TEMPERATURE RANGE OF 1325* TO 1375*F.

Claim 2

A METHOD OF MAKING A HIGH STRENGTH LOW ALLOY STEEL STRIP HAVING A MINIMUM YIELD STRENGTH OF 50,000 PSI AND GOOD FORMABILITY PROPERITIES WHICH COMPRISES SUBJECTING A SLAB OF STEEL HAVING A COMPOSITION CONSISTING ESSENTIALLY OF, BY WEIGHT, 0.10 PERCENT MAXIMUM CARBON, 0.30 TO 0.80 PERCENT MANGANESE 0.02 PERCENT MAXIMUM SULPHUR, 0.06 PERCENT ALUMINUM, 0.01 TO 0L02 COLUMBIUM, 0.06 PERCENT MAXIMUM CERIUM, THE BALANCE BEING IRON AND INCIDENTAL IMPURITIES, TO A HOT-ROLLED FINISHING TEMPERATURE IN THE RANGE OF 1620* T0 1670*F AND COLLECTING THE STRIP IN A TEMPERATURE RANGE OF 1325* TO 1375*F.

Claim 3

A method of making a high strength low alloy steel strip having a minimum yield strength of 60,000 psi and good formability properties which comprises subjecting a slab of steel having a composition consisting essentially of, by weight, 0.10 percent maximum carbon, 0.30 to 0.80 percent manganese, 0.02 percent maximum sulphur, 0.02 to 0.06 percent aluminum, 0.03 to 0.04 percent columbium, 0.06 percent maximum cerium, the balance being iron and incidental impurities, to a hot-rolled finishing temperature in the range of 1620*to 1670*F and collecting the strip in a temperature range of 1250* to 1300*F.

Claim 4

A method of making a high strength low alloy steel strip having a minimum yield strength of 60,000 psi and good formability properties which comprises subjecting a slab of steel having a composition consisting essentially of, by weight, 0.10 percent maximum carbon, 0.30 to 0.80 percent manganese, 0.02 percent maximum sulphur, 0.02 to 0.06 percent aluminum, 0.03 to 0.04 percent columbium, 0.06 percent maximum cerium, the balance being iron and incidental impurities, to a hot-rolled finishing temperature in the range of 1620*to 1670*F and collecting the strip in a temperature range of 1250* to 1300*F.

Claim 5

A method of making a high strength low alloy steel strip having a minimum yield strength of 70,000 psi good formability properties which comprises subjecting a slab of steel having a composition consisting essentially of, by weight, 0.10 percent maximum carbon, 0.30 to 0.80 percent manganese, 0.02 percent maximum sulphur, 0.02 to 0.06 percent aluminum, 0.06 to 0.08 percent columbium, 0.06 maximum cerium, the balance being iron and incidental impurities, to a hot-rolled finishing temperature in the range of 1650*F to 1700*F and collecting the strip in a temperature range of 1200* to 1250 *F.

Claim 6

A method of making a high strength low alloy steel strip having a minimum yield strength of 70,000 psi good formability properties which comprises subjecting a slab of steel having a composition consisting essentially of, by weight, 0.10 percent maximum carbon, 0.30 to 0.80 percent manganese, 0.02 percent maximum sulphur, 0.02 to 0.06 percent aluminum, 0.06 to 0.08 percent columbium, 0.06 maximum cerium, the balance being iron and incidental impurities, to a hot-rolled finishing temperature in the range of 1650*F to 1700*F and collecting the strip in a temperature range of 1200* to 1250 *F.

Claim 7

A method of making a high strength low alloy steel strip having a minimum yield strength of 80,000 psi and good formability properties which comprises subjeCting a slab of steel having a composition consisting essentially of, by weight, 0.10 percent maximum carbon, 0.30 to 0.80 percent manganese, 0.02 percent maximum sulphur, 0.02 to 0.06 percent aluminum, 0.10 to 0.12 percent columbium, 0.06 percent maximum cerium, the balance being iron and incidental impurities, to a hot-rolled finishing temperature in the range of 1650*F to 1700*F and collecting the strip in a temperature range of 1150* to 1200*F.

Claim 8

A method of making a high strength low alloy steel strip having a minimum yield strength of 80,000 psi and good formability properties which comprises subjeCting a slab of steel having a composition consisting essentially of, by weight, 0.10 percent maximum carbon, 0.30 to 0.80 percent manganese, 0.02 percent maximum sulphur, 0.02 to 0.06 percent aluminum, 0.10 to 0.12 percent columbium, 0.06 percent maximum cerium, the balance being iron and incidental impurities, to a hot-rolled finishing temperature in the range of 1650*F to 1700*F and collecting the strip in a temperature range of 1150* to 1200*F.