Ak Steel Properties, Inc.

Other

Robert J Comstock

Jerry W Schoen

Norris A Dahlstrom

George A Paraskos

To improve the formability of dual phase steels, the martensite phase is tempered. It may form a ferrite-carbide structure. The tempering step occurs after martensite has been formed in the dual phase steel. The tempering step can occur in a box annealing step or it can be performed in a continuous fashion, such as on a continuous annealing, continuous tempering heat treating, or continuous coating line. The tempering step can further comprise a temper rolling on a temper mill after the heating step.

High formability dual phase steel

The present invention provides a method of producing a high permeability grain oriented electrical steel having excellent mechanical and magnetic properties. A hot band having a thickness of about 1.5 to about 4.0 mm has a chemistry comprising about 2.5 to about 4.5% silicon, about 0.1 to about 1.2% chromium, about 0.02 to about 0.08% carbon, about 0.01 to about 0.05% aluminum, up to about 0.1% sulfur, up to about 0.14% selenium, about 0.03 to about 0.15% manganese, up to about 0.2% tin, up to about 1% copper, and balance being essentially iron and residual elements, all percentages by weight. The band has a volume resistivity of at least about 45 &#x3bc;&#x3a9;-cm, an austenite volume fraction (&#x3b3;) of at least 20% and the strip has an isomorphic layer thickness of at least about 2% of the total thickness on at least one surface of the hot processed band. The band is rapidly cooled after the anneal prior to cold rolling at a rate of at least 30&#xb0; C./second from 875-950&#xb0; C. to a temperature below 400&#xb0; C. The band is cold reduced in one or more stages with a final reduction of at least 80%, annealed, decarburized and coated with an annealing separator on at least one side. A final annealing provides stable secondary grain growth and a permeability measured at 796 A/m of at least 1840.

High permeability grain oriented electrical steel

The present invention relates to a method for producing a non-oriented electrical steel with improved magnetic properties and improved resistance to ridging, brittleness, nozzle clogging and magnetic aging. The chromium bearing steel is produced from a steel melt which is cast as a thin slab or conventional slab, cooled, hot rolled and/or cold rolled into a finished strip. The finished strip is further subjected to at least one annealing treatment wherein the magnetic properties are developed, making the steel sheet of the present invention suitable for use in electrical machinery such as motors or transformers.

Method for production of non-oriented electrical steel strip

Non-oriented electrical steels are widely used as the magnetic core material in a variety of electrical machinery and devices, particularly in motors where low core loss and high magnetic permeability in all directions of the strip are desired. A method for producing a non-oriented electrical steel with low core loss and high magnetic permeability provides a steel that is produced from a steel melt which is cast as a thin strip or sheet, cooled, hot rolled and/or cold rolled into a finished strip. The finished strip is further subjected to at least one annealing treatment wherein the magnetic properties are developed, making the steel strip suitable for use in electrical machinery such as motors or transformers.

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Trenton, OH, United States of America

Robert J Comstock