Armco Inc.

Shultz Steel Company

National Oilwell, Inc.

Baltimore Specialty Steels Corporation

James N Cordea

Harshad V Sheth

Joseph C Jasper

Dennis M Smith

William J Scumacher

Anthony Vinter

Mark J Gore

A strip casting apparatus having a roll shell with a nitrided inner diameter surface mounted on a steel core and method of manufacturing the same. The inner diameter of a steel roll shell may be nitrided by ion or plasma nitriding. The nitriding process can form tight, crack free nitride layer that provides a corrosion resistant barrier and exhibits a surface hardness that is greater than the surface hardness of the steel core and that improves galling resistance while maintaining efficient heat transfer of the roll shell. After nitriding, the roll shell can be shrink fit over a steel core.

Galling and corrosion resistant inner diameter surface in aluminum caster roll shell steels

A lean alloy steel and roll shells made of same are provided. The lean alloy steel has improved properties in imparting high productivity and long service life for roll shells (or roll caster shells) utilized in the direct casting of molten materials (such as molten aluminum) to strips. The lean alloy steel includes iron (Fe) alloyed with carbon (C), chromium (Cr), molybdenum (Mo), vanadium (V), manganese (Mn), nickel (Ni), phosphorus (P), sulfur (S), silicon (Si), and/or niobium (Nb). The roll shells made from the heat treated lean alloy steel have high resistance to surface heat checking due to its very high yield strengths at molten aluminum temperatures (made, e.g., possible with its high carbide content), and have high casting speeds because of its high thermal conductivity (made, e.g., possible with its lean alloy composition).

Composition and method of forming high productivity, continuous casting roll shell alloy

An alloy steel having particular utility for roll caster shells used in the direct casting of molten aluminum to sheet, consisting essentially of, in weight %, 0.25-0.45% C, 1.75-3.75% Cr, 0.75-2.5% Mo, 0.35 to 0.8% V, 0.4-1% Mn, greater than 0.4-1% Ni, 0.02% max P, 0.02% max S, up to 0.35% Si and balance essentially Fe. Roll caster shells fabricated from the steel have excellent toughness and ductility at room temperature to enable a greater shrink-fit with the core. The shells also have good resistance to heat checking. The excellent properties are provided by a controlled amount of Mo.sub.2 C and VC as well as limiting the amount of C in solution.

Alloy steel roll caster shell

A nonmagnetic austenitic stainless steel and articles produced therefrom, such as drill collars, having a 0.2% yield strength of at least 690 N/mm.sup.2 (100 ksi), excellent resistance to intergranular stress corrosion, good ductility, good corrosion resistance, very low magnetic permeability (less than 1.004) and resistance to galling and wear which is typically at least 50% better than found in previous drill collars, the steel and articles consisting essentially of, in weight percent, from greater than 0.05% to about 0.10% carbon, greater than 18% to about 22% manganese, about 12.5% to about 17% chromium, about 1.5% to about 5% nickel, about 0.2% to about 0.4% nitrogen, about 0.2% to about 0.7% vanadium, about 1% maximum copper, about 1% maximum molybdenum, about 2% to about 4% silicon, about 0.05% maximum phosphorus, about 0.03% maximum sulfur and balance essentially iron.

High strength austenitic stainless steel having excellent galling

A nonmagnetic austenitic stainless steel and articles such as drill collars or boat shafts fabricated therefrom, the steel having a 0.2% yield strength of at least 100 ksi (689 N/mm.sup.2), improved resistance to intergranular stress corrosion, good ductility, good corrosion resistance and low magnetic permeability, and consisting essentially of, in weight percent, from greater than 0.05% to about 0.10% carbon, greater than 14% to about 18% manganese, about 15% to about 20% chromium, about 1% to about 3.5% nickel, about 0.3% to about 0.55% nitrogen, about 0.10% to about 0.5% vanadium, about 1.0% maximum copper, about 1.0% maximum molybdenum, about 1.0% maximum silicon, about 0.04% maximum phosphorous, about 0.03% maximum sulfur, and balance essentially iron.

Austenitic stainless steel combining strength and resistance to

A non-magnetic austenitic stainless steel, and a drill collar fabricated therefrom solely by hot forging, the steel having a 0.2% yield strength of at least 85 ksi in the hot worked condition, high stress corrosion cracking resistance, good ductility, and low magnetic permeability even if cold worked, and consisting essentially of, in weight percent, from 0.12% to 0.20% carbon, 11% to 14% manganese, about 16% to about 19% chromium, 1.5% to 2.7% nickel, 0.30% to 0.45% nitrogen, 0.5% to 1.0% copper, about 0.75% maximum molybdenum, about 0.80% maximum silicon, about 0.04% maximum phosphorus, about 0.025% maximum sulfur, and balance essentially iron, with the carbon:nitrogen ratio not greater than 0.6:1.

Austenitic stainless steel and drill collar

Alloy steel having particular utility for roll caster shells used in the direct casting of molten aluminum to sheet, consisting essentially of from 0.50% to 0.60% carbon, about 0.40% to about 1.0% manganese, 0.10% to 0.30% silicon, about 0.02% maximum phosphorus, about 0.02% maximum sulfur, 0.40% to 0.90% nickel, 1.50% to 3.00% chromium, 0.80% to 1.20% molybdenum, 0.30% to 0.50% vanadium, and balance essentially iron. Caster shells fabricated from the steel exhibit markedly longer service life.

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Largo, FL, United States of America

James N Cordea