Nucor Corporation

Eric Young

Tao Wang

James W Watson

Chad Baudendistel

A weathering steel made by preparing a molten melt producing an as-cast carbon alloy steel strip with a corrosion index of at least 6.0 comprising, by weight, 0.02%-0.08% carbon, &#x3c;0.6% silicon, 0.2%-2.0% manganese, &#x3c;0.03% phosphorus, &#x3c;0.01% sulfur, &#x3c;0.01% nitrogen, 0.2%-0.5% copper, 0.01%-0.2% niobium, 0.01%-0.2% vanadium, 0.1%-0.4% chromium, 0.08%-0.25% nickel, &#x3c;0.01% aluminum, and the remainder iron and impurities. The molten melt is solidified and cooled into a cast strip 4 mm in thickness in a non-oxidizing atmosphere. The strip is hot rolled in an austenitic temperature range above Arto between 10% and 50% reduction, cooled at above 20&#xb0; C./s and coiled below 700&#xb0; C. to form a steel strip with a microstructure comprising bainite and acicular ferrite with more than 70% niobium in solid solution. Then, age hardening the strip resulting in a yield strength of at least 550 MPa and a total elongation of at least 8%.

Weathering steel

A method of making floor plate includes assembling a pair of casting rolls laterally disposed to form a nip, assembling a hot rolling mill downstream of the nip having work rolls with a surface pattern forming the negative of a raised slip-resistant pattern desired in a floor plate, introducing molten metal through at least one metal delivery nozzle to form a casting pool supported on the casting rolls above the nip; counter rotating the casting rolls to form shells on the casting surfaces of the casting rolls to cast metal strip of less than 2.2 mm thickness downwardly from the nip, and delivering the cast metal strip to and through the hot rolling mill to form by the negative of the slip-resistant pattern on the work rolls a raised slip-resistant pattern of between 0.3 and 0.7 mm in height in a floor plate of less than 1.7 mm thickness.

System for making thin floor plate

A method of making weathering steel by preparing a molten melt producing an as-cast carbon alloy steel strip with a corrosion index of at least 6.0 comprising, by weight, 0.02%-0.08% carbon, &#x3c;0.6% silicon, 0.2%-2.0% manganese, &#x3c;0.03% phosphorus, &#x3c;0.01% sulfur, &#x3c;0.01% nitrogen, 0.2%-0.5% copper, 0.01%-0.2% niobium, 0.01%-0.2% vanadium, 0.1%-0.4% chromium, 0.08%-0.25% nickel, &#x3c;0.01% aluminum, and the remainder iron and impurities. The molten melt is solidified and cooled into a cast strip &#x2264;4 mm in thickness in a non-oxidizing atmosphere. The strip is hot rolled in an austenitic temperature range above Arto between 10% and 50% reduction, cooled at above 20&#xb0; C./s and coiled below 700&#xb0; C. to form a steel strip with a microstructure comprising bainite and acicular ferrite with more than 70% niobium in solid solution. Then, age hardening the strip resulting in a yield strength of at least 550 MPa and a total elongation of at least 8%.

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Richwood, OH, United States of America

Eric Young