Inland Steel Company

Other

Yong-Wu Kim

William A Carter

Brian A Sok

Harvie Ho Lee

Phillip L Coduti

A method and apparatus for hot-rolling a slab of steel in which a cast slab is heated in a tunnel furnace to a hot-rolling temperature, rolled to a lesser thickness in a tandem mill, reheated in the same tunnel furnace and then rerolled in the same tandem mill to a final thickness.

Continuously cast carbon and stainless steel hot-rolling mill

The molten exterior surface portion of a hot dip galvanized steel strip is solidified after the strip is withdrawn from a bath of molten zinc by spraying finely divided particles of a liquid nucleating agent for initiating solidification. The particles are sprayed into an electrostatic field alongside the strip. The particles are initially directed along a path which avoids impingement against the strip. However, the smaller particles are attracted to the strip under the influence of the electrostatic field, to initiate solidification. The larger particles have a momentum along their path large enough to resist the influence of the electrostatic field, thereby permitting the larger particles to continue along a path which avoids impingement. This minimizes the formation of undesirably large spangles and an undesirable surface appearance on the strip.

Minimization of spangling on hot dip galvanized steel strip

The loss of zinc by vaporization when heating a zinc-aluminum coating to a temperature between about 427.degree. C. and 816.degree. C. (800.degree. F. and 1500.degree. F.) is significantly reduced by applying a zinc-aluminum coating containing about 30 to 75 weight percent zinc and the balance essentially aluminum to a mild carbon steel base which contains titanium in an amount sufficient to combine with all of the carbon in the steel and provide a small excess of uncombined titanium in the steel base, thereby providing a zinc-aluminum coated steel article which has improved corrosion and oxidation resistance when heated at temperatures between about 427.degree. C. and 816.degree. C. (800.degree. F. and 1500.degree. F.).

Reduction of loss of zinc by vaporization when heating zinc-aluminum

An aluminum coated low alloy low carbon killed steel sheet material which exhibits increased resistance to subsurface oxidation at elevated temperatures having incorporated in the low carbon killed steel before rolling and hot-dip aluminum coating an amount of vanadium or a combination of vanadium and titanium at least four times the weight percent carbon in the steel but not more than ten times the weight percent carbon in said steel with said amount being sufficient to combine with all the carbon and nitrogen in the steel and provide an excess of uncombined vanadium in the steel of about 0.1 wt. %.

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Munster, IN, United States of America

Yong-Wu Kim