Patents Assigned to Armco Inc.
  • Patent number: 6855213
    Abstract: A ferritic non-ridging stainless steel and process therefor. A chromium alloyed steel melt containing sufficient titanium and nitrogen but a controlled amount of aluminum is cast into an ingot or continuously cast into a strip or a slab having an as-cast fine equiaxed grain structure substantially free of columnar grains. The as-cast steel contains 0.08% C, at least about 8% Cr, up to 1.50% Mn, <0.020% Al, ?0.05% N, ?1.5% Si, <2.0% Ni, Ti?0.10%, the ratio of (Ti√óN)/Al?0.14, all percentages by weight, the balance Fe and residual elements. Preferably, the titanium is controlled so that (Ti/48)/[(C/12)+(N/14)]>1.5. A hot processed sheet may be formed from a continuously cast slab without grinding the surfaces of the slab. The hot processed sheet may be descaled, cold reduced to a final thickness and recrystallization annealed. Annealing the hot processed sheet prior to cold reduction is not required to obtain an annealed sheet essentially free of ridging and having high formability.
    Type: Grant
    Filed: September 15, 1998
    Date of Patent: February 15, 2005
    Assignee: Armco Inc.
    Inventors: Eizo Yoshitake, Alan R. McKague
  • Patent number: 6474402
    Abstract: Casting molten metal using a segmented roll for casting continuous metal strip. A strip caster (10) for producing a continuous strip (18) includes a tundish for containing a melt and a pair of horizontally disposed water cooled composite casting rolls (84). The casting rolls are juxtaposed relative to one another for forming a pouring basin (16) for receiving molten metal. The composite rolls are formed from a plurality of annular segments (45). Each segment preferably includes at least a pair of coolant openings (34) and means for aligning the coolant openings, such as a pair of alignment openings (26). The segments are axially aligned and structurally connected by a pair of connecting rods (42) extending completely across the width of the roll through the alignment openings and through appropriate end plates (96). Each roll includes a load supporting spindle (86) with each end of the roll sealed by a rotary seal (88).
    Type: Grant
    Filed: July 2, 1999
    Date of Patent: November 5, 2002
    Assignee: Armco Inc.
    Inventors: James R. Sauer, Ronald J. O'Malley, Robert S. Williams
  • Patent number: 6088895
    Abstract: This invention relates to a process for producing a cold rolled, recrystallation annealed, stainless steel strip having lustrous surfaces without being hot band annealed and/or pickled prior to cold reduction. The process includes the sequential steps of tension leveling to crack the scale and flatten a hot processed metal strip, shot blasting the strip to ablatively remove the scale and to provide a surface roughness less than 3.6 micron Ra using at least two pairs of wire brushes positioned adjacent to both surfaces of the strip with these cleaning brushes being rotated in opposite directions relative to each other to mechanically remove any residual scale. The mechanically cleaned strip then is mechanically polished with another pair of brushes to reduce the roughness to less than 2.0 micron Ra, cold reduced to have a surface roughness less than 0.4 micron Ra and recrystallization annealed. The particulate shot has a size of 0.10-0.50 mm.
    Type: Grant
    Filed: January 21, 1999
    Date of Patent: July 18, 2000
    Assignee: Armco Inc.
    Inventors: Christian D. Nelson, Christopher M. Kovscek, Jerald W. Leeker
  • Patent number: 6074600
    Abstract: This invention relates to modifying the inside bottom surface of a tundish for continuous casting molten steel to minimize turbulence thereby reducing gas bubble and slag entrainment during continuous casting of steel, especially when initially filling of the tundish. Turbulence mitigation tends to avoid entrapment of oxide inclusions in a cast slab. This invention is for an elongated tundish (10) including a pair of spaced refractory lined side walls (12) disposed in a longitudinal direction, a pair of spaced refractory lined end walls (14) extending in a lateral direction between the side walls, a refractory lined floor (16), a molten metal impact pad (18) and a molten steel outlet (20). A refractory lined weir (26) is positioned between the impact pad and the steel outlet. A refractory ramp (34) is positioned between the weir and the steel outlet. The ramp is mounted to the floor and extends the full width of the floor in the lateral direction contacting each of the side walls.
    Type: Grant
    Filed: May 26, 1999
    Date of Patent: June 13, 2000
    Assignee: Armco Inc.
    Inventors: Mark A. Suer, Donald J. Wolf
  • Patent number: 5955201
    Abstract: The present invention relates to a nonoriented electrical steel sheet coated on both surfaces with a cured insulative coating for providing a high level of surface resistivity to minimize interlaminar power losses. The cured insulative coating on the steel sheet includes, based upon 100 parts by dry weight, 20-60 parts of aluminum phosphate, 20-70 parts of at least one inorganic particulate silicate and 10-25 parts of an acrylic resin. The cured coating is formed from an acid aqueous suspension that may include up to 1 part by weight of a water-soluble organic solvent per each part of the resin. The aqueous suspension has a pH of about 2-2.5, a silicate particle size of 0.3-60 .mu.m, a resin particle size of less than 1 .mu.m, less than about 0.5 wt. % unreacted phosphoric acid and a specific gravity of about 1.0-1.3. The silicate may be one or more from the group consisting of aluminum silicate, aluminum potassium silicate and magnesium silicate.
    Type: Grant
    Filed: December 19, 1997
    Date of Patent: September 21, 1999
    Assignee: Armco Inc.
    Inventors: Dannie S. Loudermilk, Jack L. Brown
  • Patent number: 5783622
    Abstract: A stainless steel sheet suitable for use in the manufacture of an exhaust component. The steel sheet has at least one surface pretreated with a protective coating resistant to delamination at temperatures up to about 540.degree. C. including an inner inorganic portion and an outer organic portion. The inorganic portion includes at least 50 mg/m.sup.2 of a chromium based conversion coating having a thickness no greater then 0.02 mm. The conversion coating contains particulate silica with the weight ratio of chromium to silica within the range of 1:1 to 2:1. The outer organic portion includes a silicone paint containing 40-60 wt. % silicone resin. The silicone paint is dried at a temperature less than 300.degree. C. in less than one minute and then coated with a copolymer of a thermoplastic acrylic and a lubricant or a polymeric olefin. The acrylic copolymer contains 5-70 wt. % of the lubricant and the polymeric olefin contains 90% olefin resin.
    Type: Grant
    Filed: May 5, 1997
    Date of Patent: July 21, 1998
    Assignee: Armco Inc.
    Inventors: Ashok Sabata, Joseph A. Douthett, Sherman E. Winkle, Sr.
  • Patent number: 5779819
    Abstract: The present invention relates to the production of a grain oriented electrical steel composition having a volume resistivity of at least 50 micro-ohm-cm. The melt composition of the steel consists essentially of, in weight %, about 0.08% max carbon, about 0.015 to about 0.05% aluminum, about 2.25 to 7% silicon, greater than about 0.5% manganese.sub.eq, about 0.001 to about 0.011% nitrogen, about 0.01% max sulfur, about 3% max chromium, about 1% max copper, about 2% max nickel and balance essentially iron. High levels of silicon are balanced with a manganese equivalent relationship which permits lower levels of carbon while still providing the desired levels of austenite during rolling and annealing. The processing also includes the addition of excess nitrogen to the steel prior to secondary grain growth which is subsequently removed during a purification treatment.
    Type: Grant
    Filed: February 20, 1997
    Date of Patent: July 14, 1998
    Assignee: Armco Inc.
    Inventor: Glenn Stuart Huppi
  • Patent number: 5749939
    Abstract: A multiple stage process for obtaining Ni units from Ni laterite ores and sulfur-bearing Ni concentrates during production of nickel-alloyed iron, nickel-alloyed steel or nickel-alloyed stainless steel in a reactor equipped with top- and bottom-blowing means. Dried Ni laterite ore is charged into an iron/slag bath mixture containing dissolved carbon and a metalloid reductant such as aluminum or silicon. The laterite ore is melted while heat is generated by oxidation of the metalloid and carbon in the reactor. After the laterite ore is melted, top-blowing of pure oxygen and bottom-blowing of an oxygen-containing gas are ceased. Bottom injection of an inert stirring gas is begun. A sulfur-bearing Ni concentrate and aluminum are added to the bath.
    Type: Grant
    Filed: December 4, 1996
    Date of Patent: May 12, 1998
    Assignee: Armco Inc.
    Inventor: David M. Kundrat
  • Patent number: 5743968
    Abstract: A process for removing scale from stainless steel using an aqueous solution containing hydrogen peroxide and an inorganic acid, i.e., hydrochloric or sulfuric acid. A hot rolled or annealed stainless steel strip (10) covered with scale is immersed into hot inorganic acid contained within pickling tanks (12) and (14). Thereafter, the strip may have residual amounts of tightly adherent scale (11). This scale is activated by a solution containing the inorganic acid and hydrogen peroxide applied to the strip such as by a spray header (16) extending completely transversely across and positioned above the strip and another spray header (18) extending completely transversely across and positioned below the strip. It may be desirable to pass the activated strip through the hot inorganic acid again and reactivate the strip at very high line speeds to insure complete removal of scale from the strip. Any hydrogen peroxide spray dripping from the strip is collected on a catch pan (30) and flowed into a tank (28).
    Type: Grant
    Filed: March 20, 1997
    Date of Patent: April 28, 1998
    Assignee: Armco Inc.
    Inventors: Jerald W. Leeker, Ronald D. Rodabaugh
  • Patent number: 5736709
    Abstract: The invention relates to an apparatus for using laser radiation to remove an oxide layer (scale) by vaporization from a hot rolled or annealed steel strip (40) traveling in a gravitationally vertical direction at a speed of at least 10 m/min. The apparatus includes a high power laser such as a free electron laser and a sealed interaction chamber (90) containing a non-oxidizing gas (108). The electromagnetic radiation from the laser has a surface power density of at least about 5 MW/cm.sup.2 at a point of contact with the metal strip surface. The radiation is passed through an optical system of aligned lenses or mirrors for focusing the radiation into a straight line projected transversely completely across the strip. The radiation has a pulse width less than 100 picoseconds, a pulse repetition rate greater than 10 MHz and a high average power of at least 10 kW.
    Type: Grant
    Filed: August 12, 1996
    Date of Patent: April 7, 1998
    Assignee: Armco Inc.
    Inventor: Gary L. Neiheisel
  • Patent number: 5702502
    Abstract: A three-stage process for obtaining metallic Cr units insitu during the production of stainless steel. Raw chromite ore or a concentrate produced from chromite ore is mixed with a carbonaceous reductant and slagging agents are added to an iron bath (24) for smelting and refining in a refining reactor (10). During the first stage, partially metallized chromite is smelted by carbon in the reactor that is top-and bottom-blown with oxygen and oxygen-containing gases respectively to produce a chromium alloy bath having a carbon content well below saturation. In the second stage, the alloy bath is decarburized by being bottom stirred with the oxygen-containing gas to the final bath carbon specification. In the third stage, the alloy bath is reduced by a metalloid reductant such as silicon or aluminum and again bottom stirred but with a non-oxidizing gas to achieve a high chromium yield.
    Type: Grant
    Filed: December 14, 1995
    Date of Patent: December 30, 1997
    Assignee: Armco Inc.
    Inventors: David M. Kundrat, Allan M. Smillie, Richard C. Sussman
  • Patent number: 5702534
    Abstract: A process for removing scale from stainless steel using an aqueous solution containing hydrogen peroxide. A hot rolled or annealed stainless steel strip (10) covered with scale is immersed into hot sulfuric acid contained within tanks (12) and (14). Thereafter, the strip may have residual amounts of tightly adherent scale (11). This scale is activated by the aqueous solution containing hydrogen peroxide applied to the strip such as by a spray header (16) extending completely transversely across and positioned above the strip and another spray header (18) extending completely transversely across and positioned below the strip. Any peroxide spray dripping from the, strip is collected on a catch pan (30) and flowed into a tank (28). Preferably, the peroxide solution is a dilute concentration of the acid in tanks (12) and (14). The hydrochloric acid removes smut from the strip formed by the sulfuric acid to improve the cleanliness of the pickled strip.
    Type: Grant
    Filed: May 24, 1996
    Date of Patent: December 30, 1997
    Assignee: Armco Inc.
    Inventors: Ronald D. Rodabaugh, Jerald W. Leeker
  • Patent number: 5702539
    Abstract: The present invention provides a method of producing grain oriented electrical steel having excellent mechanical and magnetic properties. A hot processed strip having a thickness of 1.5-4.0 mm thickness a composition consisting essentially of 2.5-4.5% silicon, 0.1-1.2% chromium, less than 0.050% carbon, less than 0.005% aluminum, up to 0.1% sulfur, up to 0.14% selenium, 0.01-1% manganese and balance being essentially iron and residual elements, all percentages by weight. The strip has a volume resistivity of at least 45 .mu..OMEGA.-cm, at least 0.010% carbon so that an austenite volume fraction (.gamma..sub.1150.degree. C.) of at least 2.5% is present in the hot processed strip and each surface of the strip has an isomorphic layer having a thickness of at least 10% of the total thickness of the hot processed strip. The strip is cold reduced to an intermediate thickness, annealed, cold reduced to a final thickness and decarburized to less than 0.003% carbon.
    Type: Grant
    Filed: February 28, 1997
    Date of Patent: December 30, 1997
    Assignee: Armco Inc.
    Inventors: Jerry W. Schoen, Norris A. Dahlstrom, Christopher G. Klapheke
  • Patent number: 5688010
    Abstract: A coil lifter (26) adapted for being suspended from an overhead crane for lifting a coil (10) of strip material having a central opening (14). The lifter includes a vertical lifting arm (28), an upper portion (34), a lower portion (36), a lifting surface (42) on the lower arm portion for being inserted into and contacting a curvature (44) of the central opening of the coil. The lifting arm includes a facing surface (30) adjacent to a coil edge (16, 18), side surfaces (32, 33) and a pair of spaced apart rollers (46, 48) made from an elastic laminated material (72) for preventing damage to the edge of the coil. The rollers are rotatably supported by the lifting arm so that an annular outer surface (50) of each roller extends to a position between the coil edge and the facing surface.
    Type: Grant
    Filed: June 10, 1996
    Date of Patent: November 18, 1997
    Assignee: Armco Inc.
    Inventor: William K. Moyer
  • Patent number: 5651412
    Abstract: A strip caster (10) for producing a continuous strip (24) includes a tundish (12) for containing a melt (14), a pair of horizontally disposed water cooled casting rolls (22) and devices (29) for electrostatically coating the outer peripheral chill surfaces (44) of the casting rolls with a powder flux material (56). The casting rolls are juxtaposed relative to one another for forming a pouting basin (18) for receiving the melt through a teeming tube (16) thereby establishing a meniscus (20) between the rolls for forming the strip. The melt is protected from the outside air by a non-oxidizing gas passed through a supply line (28) to a sealing chamber (26). A preferred flux is boron oxide having a melting point of about 550.degree. C. The flux coating enhances wetting of the steel melt to the casting roll and dissolves any metal oxide formed on the roll.
    Type: Grant
    Filed: October 6, 1995
    Date of Patent: July 29, 1997
    Assignee: Armco Inc.
    Inventors: Robert S. Williams, Ronald J. O'Malley, Richard C. Sussman
  • Patent number: 5651413
    Abstract: A strip caster (10) for producing a continuous strip (24) has a tundish (12) for containing a melt (14) and a pair of horizontally disposed water cooled casting rolls (22). The casting rolls are juxtaposed relative to one another for forming a pouring basin (18) for receiving the melt through a teeming tube (16) thereby establishing a meniscus (20) between the rolls for forming a strip (24). The melt is protected from the outside air by a non-oxidizing gas passed through a supply line (28) to a sealing chamber (26). Devices (29) for conditioning the outer peripheral chill surfaces of the casting rolls includes grit blasting nozzles (30A, 30B, 30C, 30D), a collection trough (32) for gathering the grit, a line (34) for recycling the grit to a bag house (36), a feeder (38) and a pressurized distributor (40) for delivering the grit to the nozzles. The conditioning nozzles remove dirt, metal oxides and surface imperfections providing a clean surface readily wetted by the melt.
    Type: Grant
    Filed: October 6, 1995
    Date of Patent: July 29, 1997
    Assignee: Armco Inc.
    Inventors: Robert S. Williams, Steven L. Campbell
  • Patent number: 5643370
    Abstract: The present invention relates to the production of a grain oriented electrical steel composition having a volume resistivity of at least 50 micro-ohm-cm. The melt composition of the steel consists essentially of, in weight %, about 0.08% max carbon, about 0.015 to about 0.05% aluminum, 2.25 to 7% silicon, greater than about 0.5% manganese.sub.eq, about 0.001 to about 0.011% nitrogen, about 0.01% max sulfur, about 3% max chromium, about 1% max copper, about 2% max nickel and balance essentially iron. High levels of silicon are balanced with a manganese equivalent relationship which permits lower levels of carbon while still providing the desired levels of austenite during rolling and annealing. The processing also includes the addition of excess nitrogen to the steel prior to secondary grain growth which is subsequently removed during a purification treatment.
    Type: Grant
    Filed: May 16, 1995
    Date of Patent: July 1, 1997
    Assignee: Armco Inc.
    Inventor: Glenn Stuart Huppi
  • Patent number: 5591531
    Abstract: Steel alloys containing chromium may be hot dip aluminized in a bath having up to 15% silicon with improved wettability by using a bright preannealing practice in a box furnace having a substantially pure hydrogen atmosphere. The surfaces of the preannealed steel are easily coated if the box annealing furnace has a dew point of less than -60.degree. C. (-75.degree. F.). The preannealing should also include a minimum soak of at least 1 hour at a temperature of 675.degree. C. to 785.degree. C. (1250.degree. F. to 1450.degree. F.). It is important that the surfaces of the strip after preannealing are not removed prior to aluminizing. During the aluminizing operation, the strip temperature does not need to be heated to much above the bath temperature since the strip has already been preannealed. The furnace is maintained to avoid oxidation with an atmosphere which is typically a nitrogen, hydrogen or a hydrogen-nitrogen mixture.
    Type: Grant
    Filed: May 23, 1995
    Date of Patent: January 7, 1997
    Assignee: Armco Inc.
    Inventor: Joseph C. Jasper
  • Patent number: 5575829
    Abstract: A process for obtaining Ni units from sulfur-bearing nickel concentrate during refining a nickel-alloyed steel or a stainless steel. Sulfur of the concentrate is transferred to and held within the slag by controlling slag composition and temperature, degree of mixing of the slag with the bath by an inert gas and aluminum level in the bath. The extent of desulfurization by the slag, the slag weight and the steel sulfur specification determine the amount of concentrate that can be added to the bath. The ratio of the slag weight to the iron bath weight should be in the range of 0.10-0.30 and the bath temperature is maintained between 1550.degree.-1700.degree. C. The slag basicity is controlled between 1.0 and 3.5, the composition of Al.sub.2 O.sub.3 in the slag is maintained between 15-25 wt. % and the composition of MgO is maintained between 12-20 wt. %.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: November 19, 1996
    Assignee: Armco Inc.
    Inventor: David M. Kundrat
  • Patent number: 5567224
    Abstract: Method of reducing metal oxide in a rotary hearth furnace (14) to make a feed stock for a refining vessel when manufacturing alloyed iron, alloyed steel or stainless steel. The rotary hearth furnace includes an annular inner refractory wall (32), an annular outer refractory wall (34), an annular refractory platform (33) between the two walls. Stationary fuel burners (36, 40) are mounted to walls (32, 34) at a position just above an upper surface of the platform. A mixture of a metal oxide and a carbonaceous reductant is placed onto the upper surface of the platform and rotated past the burners. The oxide is heated by an oxidizing flame. Thereafter, a second layer of a reductant is charged over the hot first layer, and both layers are heated for an additional period of time to a temperature of at least 1300.degree. C. to reduce the metal oxide. The metal oxide may be chromium ore, chromium ore concentrate, nickel ore, nickel ore concentrate and stainless steel flue dust. The reductant may be coal or coke.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: October 22, 1996
    Assignee: Armco Inc.
    Inventor: David M. Kundrat