Bethlehem Steel Corporation

Other

Electric Power Research Institute Incorporated

Bethlehem Steel Co.

Richard L Bodnar

Steven S Hansen

Yulin Shen

Sunday O Abraham

Robert I Jaffee

Wung-Yong Choo

Jang-Yong Yoo

Minfa Lin

Jason Thomas

Justin R Raines

Yufeng Wang

A method of making a high strength low-alloy steel includes the steps of casting an alloy steel into a cast form, hot rolling the cast form into a partially rolled form, and control rolling the partially rolled form to a rolled product. The controlled rolling is discontinued at a discontinue rolling temperature and is then acceleratedly cooled to a finish cooling temperature. The alloy steel uses a low silicon, carbon niobium, vanadium, titanium-containing steel composition. Silicon is less than 0.04% by weight, vanadium is between 0.05 and 0.10% by weight, niobium is between 0.06 and 0.14% by weight, titanium is between 0.006 and 0.02% by weight, and carbon is between 0.06 and 0.14% by weight. The controlled chemistry, controlled rolling, and accelerated cooling allows the discontinue rolling temperature to be high, thereby improving rolling productivity. The low-carbon alloy chemistry results in improvements in castability, formability, and weldability.

Composition and method for producing an alloy steel and a product therefrom for structural applications

A method of making a weathering grade steel plate includes the steps of casting, hot rolling, and accelerated cooling using a modified weathering grade alloy composition. The composition employs effective levels of manganese, carbon, niobium, molybdenum, nitrogen, and titanium. After the casting, the slab or ingot is heated and rough rolled to an intermediate gauge plate. The intermediate gauge plate is controlled finish temperature rolled and subjected to accelerated cooling. With the controlled alloy chemistry, rolling and cooling, the final gauge plate exhibits continuous yielding and can be used for applications requiring a 70 KSI minimum yield strength, a 90-110 KSI tensile strength, and a Charpy V-notch toughness greater than 35 ft-lbs. at &minus;10&deg; F. in plates up to 4.0&Prime; thick.

Method of making a weathering grade plate and product thereform

A method of making a weathering grade steel plate includes the steps of establishing a minimum yield strength:plate thickness target from one of 50 KSI:up to 4&Prime;, 65 KSI:up to 1.5&Prime;, and 70 KSI:up to 1.25&Prime;. A modified weathering grade alloy composition is cast into a slab employing effective levels of manganese, carbon, niobium, vanadium, nitrogen, and titanium. The cast slab is heated and rough rolled to an intermediate gauge plate. The intermediate gauge plate is controlled rolled and subjected to one of air cooling or accelerated cooling depending on the minimum yield strength and thickness target. With the controlled alloy chemistry, rolling and cooling, the final gauge plate exhibits discontinuous yielding and can be used for applications requiring a 70 KSI minimum yield strength in plate thicknesses up to 1.25&Prime;, a 65 KSI minimum yield strength in plate thickness up to 1.50&Prime; and a 50 KSI minimum yield strength for plates as thick as 4&Prime;.

Method of making an as-rolled multi-purpose weathering steel plate and product therefrom

A high strength low-alloy steel is subjected to a controlled rolling and accelerated cooling process to obtain minimum physical properties while achieving improved mill productivity. The alloy chemistry utilizes a low silicon, carbon, niobium, vanadium, titanium-containing steel composition which is hot worked and accelerated cooled under controlled conditions. The chemistry, controlled rolling and accelerated cooling allows for significant increase in the finishing rolling temperature thereby permitting high rolling output. The alloy chemistry includes a low-carbon grade which also has improved castability, formability and weldability.

Composition and method for producing an alloy steel and a product

A fully killed steel has a composition that is tailored to meet a 50 KSI minimum yield strength after hot rolling and accelerated cooling. The steel has a carbon content in the range of from about 0.05 to about 0.10 percent or from about 0.15 to about 0.27 percent, from about 0.005 to about 0.020 percent titanium, from about 0.004 to about 0.015 percent nitrogen, from 0 to about 0.02 percent vanadium, and the remainder iron plus incidental impurities. The steel is continuously cast, hot rolled to plate, and cooled to a temperature of less than about 1100.degree. F. at a cooling rate lying in a cooling rate band extending from about 2.degree. to about 14.degree. F./sec at 2 inches plate thickness, from about 7.degree. to about 26.degree. F./sec at 1 inch plate thickness, and from about 13.degree. to about 45.degree. F./sec at 1/2 inch plate thickness.

Method of preparing titanium-bearing low-cost structural steel

A fully killed steel has a composition of from about 0.005 to about 0.020 percent titanium and from about 0.004 to about 0.015 percent nitrogen, with the mole ratio of titanium to nitrogen being less than about 3.42. One grad e of this steel exhibiting a 42 KSI minimum yield strength has from about 0.05 to about 0.10 percent or from about 0.15 to about 0.27 percent carbon, and no more than about 0.02 percent vanadium. Another grade exhibiting a 50 KSI minimum yield strength has from about 0.15 to about 0.27 percent carbon and from about 0.02 to about 0.04 percent vanadium. The balance of each steel is iron and other elements. Copper may optionally be provided for strength and corrosion resistance. The steel is prepared by continuous casting and hot rolling, without any quenching and tempering required to achieve the desired properties.

Method for preparing titanium-bearing low-cost structural steel

A fully killed steel has a composition of from about 0.005 to about 0.020 percent titanium and from about 0.004 to about 0.015 percent nitrogen, with the mole ratio of titanium to nitrogen being less than about 3.42. One grade of this steel exhibiting a 42 KSI minimum yield strength has from about 0.15 to about 0.27 percent carbon and from 0 to about 0.04 percent vanadium. Another grade exhibiting a 50 KSI minimum yield strength has from about 0.05 to about 0.27 percent carbon and at least about 0.02 percent vanadium. The balance of each steel is iron and other elements. Copper may optionally be provided for strength and corrosion resistance. The steel is prepared by continuous casting and hot rolling, without any quenching and tempering required to achieve the desired properties.

Titanium-bearing low-cost structural steel

A modified 1% CrMoV steel of particular use in steam and gas turbine rotors contains from about 0.20 percent to about 0.35 percent carbon, less than about 0.1 percent manganese, from about 1.5 percent to about 6.5 percent nickel, from about 0.8 percent to about 2.0 percent chromium, from about 0.9 percent to about 2.0 percent molybdenum, from about 0.1 percent to about 0.4 percent vanadium, from zero to about 0.07 percent columbium, less than about 0.12 percent silicon, less than about 0.006 percent phosphorus, less than about 0.002 percent sulfur, less than about 0.005 percent antimony, less than about 0.010 percent arsenic, less than about 0.010 percent tin, less than about 0.10 percent copper, less than about 0.010 percent aluminum, balance iron totalling 100 percent, with all percentages by weight. Selected compositions of this steel can be processed to have a 50% fracture appearance transition temperature of less than ambient temperature, and do not exhibit temper embrittlement after extended periods of elevated temperature exposure. The hardenability and creep rupture properties of the modified steel are better than, or equivalent to, those of the standard 1% CrMoV steels, which are brittle at ambient temperatures and subject to temper embrittlement.

Modified 1% CrMoV rotor steel

A vanadium-nitrogen microalloyed steel is continuously hot rolled to C-shaped sections that meet property requirements for side rails of truck frames with no heat treatment. Sections with different thicknesses of the web and flange regions can also be prepared by the same processing. The composition of the steel is from about 0.16 to about 0.20 percent carbon, from about 1.2 to about 2.0 percent manganese, from about 0.45 to about 0.55 percent silicon, from about 0.10 to about 0.30 percent vanadium, from about 0.001 to about 0.030 percent aluminum, from about 0.010 to about 0.027 percent nitrogen, less than about 0.030 percent phosphorus, less than about 0.030 percent sulfur, balance iron totalling 100 percent, with all percentages by weight. Variations of this steel containing either from about 0.01 to about 0.02 percent titanium or 0.04 to about 0.07 percent aluminum are also permissible.

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Bethlehem, PA, United States of America

Richard L Bodnar