Patents by Inventor Walter Blejde
Walter Blejde has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20050145304Abstract: A molten steel having a slag of iron, manganese, silicon and aluminum oxides is formed and passed between a pair of casting rolls to form the steel strip having MnO.SiO2.Al2O3 inclusions, the inclusions having a desired ratio of MnO/SiO2.Type: ApplicationFiled: February 7, 2005Publication date: July 7, 2005Inventors: Walter Blejde, Rama Mahapatra
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Patent number: 6818073Abstract: Steel strips and methods for producing steel strips are provided. In an illustrated embodiment, a method includes continuously casting molten low carbon steel into a strip of no more than 5 mm thickness having austenite grains that are coarse grains of 100-300 micron width; and providing desired yield strength in the cast strip by cooling the strip to transform the austenite grains to ferrite in a temperature range between 850° C. and 400° C. at a selected cooling rate of at least 0.01° C./sec to produce a microstructure that provides a strip having a yield strength of at least 200 MPa. The low carbon steel produced desired microstructure.Type: GrantFiled: April 24, 2003Date of Patent: November 16, 2004Assignee: Nucor CorporationInventors: Lazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Patent number: 6808550Abstract: A system for determining process parameters for the ladle refinement of steel includes a computer executing a number of software algorithms for determining one or more process parameters for various steel refinement process steps. In one embodiment, for example, the computer is configured to determine the total amount of flux additions to achieve a desired sulfur percentage as part of a steel desulfurization process. In another embodiment, the computer is configured to determine the total quantity of oxygen to be injected into the steel as part of a steel reoxidation process. In still another embodiment, the computer is configured to determine a melting temperature of inclusions within the refined steel, and to determine whether this melting temperature is within an acceptable range to successfully process the steel in a continuous steel strip casting apparatus/process, or whether the steel must be reworked to achieve an acceptable inclusion melting temperature.Type: GrantFiled: February 15, 2002Date of Patent: October 26, 2004Assignee: Nucor CorporationInventors: Rama Mahapatra, Walter Blejde, Joel Sommer, Scott Story, Dave Sosinsky
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Patent number: 6755234Abstract: A model-based strategy is provided for determining casting roll operating temperature in a continuous thin strip casting process. A first temperature sensor produces a first temperature signal indicative of the temperature of cooling liquid supplied to the casting rolls and a second temperature sensor produces a second temperature signal indicative of the temperature of cooling liquid temperature exiting the casting rolls. A computer determines a heat flux value as a function of the first and second temperature signals, and computes the operating temperature of the casting rolls as a function of the heat flux value, the second temperature signal and a number of constants defined by fixed-valued operating parameters of the continuous thin strip casting process. A control strategy is also provided to modify one or more operating parameters of the continuous thin strip casting process as a function of the casting roll temperature.Type: GrantFiled: April 4, 2003Date of Patent: June 29, 2004Assignee: Nucor CorporationInventors: Walter Blejde, Rama Mahapatra
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Publication number: 20040079514Abstract: A cast carbon steel strip is prepared by continuously casting in a twin roll caster and cooling to transform the strip from austenite to ferrite at a temperature range between 400° C. and 850° C. at a cooling rate of not more than about 100° C./sec, such that the strip has a yield strength of greater than 450 MPa. The cast strip before cooling is passed through a hot rolling mill to reduce the thickness of strip by at least 15% and up to 50%.Type: ApplicationFiled: October 20, 2003Publication date: April 29, 2004Inventors: Lazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Patent number: 6675869Abstract: A plain carbon steel strip is continuously cast in a twin roll caster and passes to a run out table on which it is subjected to accelerated cooling by means of cooling headers whereby it is cooled to transform the strip from austenite to ferrite at a temperature range between 850° C. and 400° C. at a cooling rate of not less than 90° C./sec, such that the strip has a yield strength of greater than 450 MPa. The strip after casting and before cooling is passed through a hot rolling mill to reduce the thickness of strip by at least 15% and up to 50%.Type: GrantFiled: September 28, 2001Date of Patent: January 13, 2004Assignee: Nucor CorporationInventors: Lazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Publication number: 20030205355Abstract: Steel strips and methods for producing steel strips are provided. In an illustrated embodiment, a method includes continuously casting molten low carbon steel into a strip of no more than 5 mm thickness having austenite grains that are coarse grains of 100-300 micron width; and providing desired yield strength in the cast strip by cooling the strip to transform the austenite grains to ferrite in a temperature range between 850° C. and 400° C. at a selected cooling rate of at least 0.01° C./sec to produce a microstructure that provides a strip having a yield strength of at least 200 MPa. The low carbon steel produced desired microstructure.Type: ApplicationFiled: April 24, 2003Publication date: November 6, 2003Inventors: Lazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Publication number: 20030205352Abstract: A model-based strategy is provided for determining casting roll operating temperature in a continuous thin strip casting process. A first temperature sensor produces a first temperature signal indicative of the temperature of cooling liquid supplied to the casting rolls and a second temperature sensor produces a second temperature signal indicative of the temperature of cooling liquid temperature exiting the casting rolls. A computer determines a heat flux value as a function of the first and second temperature signals, and computes the operating temperature of the casting rolls as a function of the heat flux value, the second temperature signal and a number of constants defined by fixed-valued operating parameters of the continuous thin strip casting process. A control strategy is also provided to modify one or more operating parameters of the continuous thin strip casting process as a function of the casting roll temperature.Type: ApplicationFiled: April 4, 2003Publication date: November 6, 2003Inventors: Walter Blejde, Rama Mahapatra
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Patent number: 6585030Abstract: Steel strips and methods for producing steel strips are provided. In an illustrated embodiment, a method includes continuously casting molten low carbon steel into a strip of no more than 5 mm thickness having austenite grains that are coarse grains of 100-300 micron width; and providing desired yield strength in the cast strip by cooling the strip to transform the austenite grains to ferrite in a temperature range between 850° C. and 400° C. at a selected cooling rate of at least 0.01° C./sec to produce a microstructure that provides a strip having a yield strength of at least 200 MPa. The low carbon steel produced desired microstructure.Type: GrantFiled: September 28, 2001Date of Patent: July 1, 2003Assignee: Nucor CorporationInventors: Lazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Patent number: 6581672Abstract: A method of controlling a continuous steel strip casting process based on customer-specified requirements includes a general purpose computer in which product specifications of steel product ordered by a customer is entered. The computer is configured to automatically map the product specifications to process parameters/set points for controlling the continuous steel strip casting process in a manner to produce the customer ordered product, and in one embodiment produces a process change report detailing such process parameters/set points for operator use in physically implementing such process parameters/set points in the strip casting process. Alternatively, the computer may provide the process parameters/set points directly to the strip casting process for automatic control thereof in producing the customer ordered steel product.Type: GrantFiled: October 1, 2001Date of Patent: June 24, 2003Assignee: Nucor CorporationInventors: Lazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Publication number: 20020062942Abstract: A method of controlling a continuous steel strip casting process based on customer-specified requirements includes a general purpose computer in which product specifications of steel product ordered by a customer is entered. The computer is configured to automatically map the product specifications to process parameters/set points for controlling the continuous steel strip casting process in a manner to produce the customer ordered product, and in one embodiment produces a process change report detailing such process parameters/set points for operator use in physically implementing such process parameters/set points in the strip casting process. Alternatively, the computer may provide the process parameters/set points directly to the strip casting process for automatic control thereof in producing the customer ordered steel product.Type: ApplicationFiled: October 1, 2001Publication date: May 30, 2002Inventors: Lazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Publication number: 20020046824Abstract: Steel strips and methods for producing steel strips are provided. In an illustrated embodiment, a method includes continuously casting molten low carbon steel into a strip and hot rolling the cast strip within a temperature range such that the strip passes through the Ar3 transformation temperature from austenite to ferrite under strain during rolling, thereby producing a strip having a yield strength above 400 Mpa and an elongation in excess of 30%. The cast steel strip has desired microstructures.Type: ApplicationFiled: September 28, 2001Publication date: April 25, 2002Inventors: Lazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Publication number: 20020043357Abstract: Steel strips and methods for producing steel strips are provided. In an illustrated embodiment, a method includes continuously casting molten low carbon steel into a strip of no more than 5 mm thickness having austenite grains that are coarse grains of 100-300 micron width; and providing desired yield strength in the cast strip by cooling the strip to transform the austenite grains to ferrite in a temperature range between 850° C. and 400° C. at a selected cooling rate of at least 0.01 ° C./sec to produce a microstructure that provides a strip having a yield strength of at least 200 MPa. The low carbon steel produced desired microstructure.Type: ApplicationFiled: September 28, 2001Publication date: April 18, 2002Inventors: Lazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Publication number: 20020043304Abstract: Steel strips and methods for producing steel strips are provided. In an illustrated embodiment, a method for producing steel strips includes continuously casting molten steel into a strip, said molten steel comprising a concentration of residuals of 2.0 wt % or less is selected with regard to the microstructure of the finished strip to provide a desired yield strength; and cooling the strip to transform the strip from austenite to ferrite in the temperature range of 850° C. to 400° C. Cast steel with improved yield strength properties is produced by such method.Type: ApplicationFiled: September 28, 2001Publication date: April 18, 2002Inventors: Lazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Publication number: 20020043358Abstract: A plain carbon steel strip is continuously cast in a twin roll caster and passes to a run out table on which it is subjected to accelerated cooling by means of cooling headers whereby it is cooled to transform the strip from austenite to ferrite at a temperature range between 850° C. and 400° C. at a cooling rate of not less than 90° C./sec, such that the strip has a yield strength of greater than 450 MPa. The strip after casting and before cooling is passed through a hot rolling mill to reduce the thickness of strip by at least 15% and up to 50%.Type: ApplicationFiled: September 28, 2001Publication date: April 18, 2002Inventors: Lazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Patent number: 5988258Abstract: Casting metal strip by delivering molten metal to a casting pool (81) supported on a pair of parallel casting rolls (16) and passing metal downwardly between the rolls to produce solidified strip (20). Flow of metal to the casting pool (81) is controlled by an input flow control valve (47). At start of casting when pool (81) is being filled speed of rolls (16) is varied in response to variations between actual instantaneous pool level and predicted level until pool approaches desired operational level. Thereafter any variations between instantaneous roll speed and desired operational roll speed are caused to adjust valve (47) to being pool level and roll speed to desired operational valves.Type: GrantFiled: March 4, 1998Date of Patent: November 23, 1999Assignees: Ishikawajima-Harima Heavy Industries Company Limited, BHP Steel (JLA) Pty LtdInventors: Walter Blejde, Christian Barlow
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Patent number: 5960856Abstract: A casting pool (30) of ferrous molten metal is supported on a pair of chilled generally horizontal casting rolls (22) forming a nip (27) between them. The casting rolls (22) rotate mutually opposite directions to produce a solidified metal strip (12) moving downwardly from the nip (27). The strip (12) passes along a transit path (10) which takes it away from the nip (27) in an unrestrained loop (29) disposed within a strip enclosure (38) within which the strip is confined through said transit path (10). The strip (12) moves downwardly from the nip (27) to form the unrestrained loop (29) passes between a pair of cooled non-contact heat absorbers (101) to which heat is radiated from the strip (12) whereby to extract from the strip heat generated by completion of solidification of metal therein after leaving the casting pool (30). Heat absorbers (101) are formed as opposite side walls of a cooling collar (100) defining an upper part of enclosure (38) and provided with cooling water ducts (102).Type: GrantFiled: September 10, 1997Date of Patent: October 5, 1999Assignees: Ishikawajima-Harima Heavy Industries Company Limited, BHP Steel (JLA) Pty. Ltd.Inventors: Walter Blejde, Hisahiko Fukase, Rama Ballav Mahapatra
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Patent number: 5488988Abstract: Method and apparatus for casting metal strip in which molten metal is introduced between a pair of parallel casting rollers (16) via a tundish (18) and metal delivery nozzle (19b). Casting rollers (16) are cooled so that shells solidify on the moving roller surfaces and are brought together at the nip between them to produce a solidified strip product (20) at the roller outlet. A casting pool is established by pouring a first batch of molten metal at a relatively high temperature above the liquidus temperature of molten metal through the delivery nozzle (19b) and is thereafter maintained by pouring through the delivery nozzle (19b) a second batch of molten metal at a relatively lower temperature. The bottom of the tundish (18) is formed with a well (26) to hold the first batch of molten metal and there is heating means (8) to heat the metal in the well (26).Type: GrantFiled: May 27, 1994Date of Patent: February 6, 1996Assignees: Ishikawajima-Harima Heavy Industries Company Limited, BHP Steel (JLA) Pty Ltd.Inventors: Hisahiko Fukase, William J. Folder, Walter Blejde
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Patent number: 5259439Abstract: Method and apparatus for casting metal strip in which molten metal is introduced between a pair of parallel casting rollers (16) via a tundish (18) and delivery nozzle (19). Casting rollers (16) are cooled so that shells solidify on the moving roller surfaces and are brought together at the nip between them to produce a solidified strip product (20) at the roller outlet. The tundish (18), delivery nozzle (19) and a pair of side closure plates (56) to confine the pool of metal on the casting rollers are separately preheated to working temperature and then rapidly brought into an operative assembly and casting is started before detrimental uneven or localized cooling of the preheated components can develop. To avoid material deterioration and metal flow irregularities due to oxidation on preheating, the delivery nozzle (19) and side closure plates (56) are provided with oxidation retarding coatings, for example in the form of ceramic glazing, or are preheated in an inert atmosphere.Type: GrantFiled: June 3, 1992Date of Patent: November 9, 1993Assignees: Ishikawajima-Harima Heavy Industries Company Limited, John LysaghtInventors: Walter Blejde, William J. Folder, Hisahiko Fukase, William J. Sinclair
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Patent number: 5221511Abstract: A method and apparatus for casting metal strip in which molten metal is introduced between a pair of parallel casting rollers via a metal delivery nozzle disposed above the nip between the rollers, wherein the delivery nozzle comprises an elongate trough to receive molten metal, a nozzle outlet slot extending longitudinally along the bottom of the trough, a baffle structure extending above the slot, and a pair of flow passage means spaced apart laterally of the trough, one to each side of the outlet slot and each providing for flow of molten metal from the trough interior above the baffle structure into the trough interior below the baffle structure.Type: GrantFiled: November 14, 1991Date of Patent: June 22, 1993Assignees: Ishikawajima-Harima Heavy Industries Co., Ltd., John Lysaght (Aus) Ltd.Inventors: Hisahiko Fukase, Walter Blejde, William J. Folder, Keith F. Pitchford, Joseph G. Herbertson