Inland Steel Company

Brian A Sok

Richard A Nickola

Shashi B Agarwal

William A Carter

Yong-Wu Kim

Albert Ray Mullins

Phillip L Coduti

Griff W Froman

Lenin F Martinez

Coatings of a powdered protective metallic material or refractory material and mixtures thereof are formed on a ferrous metal strip as a wet film dispersion in a resin binder composition of a synthetic organic resin and a volatile organic solvent compatible with said resin, and the coated strip is heated to effect curing said resin binder and forming a flexible non-tacky dry film. The metal strip having the cured dry film containing powdered protective metallic material can be subjected to varying heat treatments to provide a wide range of protective coatings having improved surface properties, including iron-protective metal diffusion alloy coatings, such as iron-aluminum diffusion alloy coatings having a surface concentration of aluminum between about 8 and 10 wt. percent aluminum, which have improved high temperature oxidation resistance after being severely strained during fabrication at room temperature.

Powder metal and/or refractory coated ferrous metals

A ferrous metal strip is provided with a wet film coating of a powder metal, powder refractory material or a mixture thereof dispersed in a resin binder composition formed of a synthetic organic resin and a volatile solvent, followed by heating the coated strip to remove the solvent and cure the organic resin. The metal strip with the cured resin-powder flexible non-tacky coating can be subjected to varying heat treatments to provide a wide range of protective coatings having improved surface properties. The formability properties of the cured resin-powder coating is further improved by applying a surface coating of a dry lubricant, such as molybdenum disulfide or graphite, as a dry powder or as a dispersion in a fluid vehicle.

Powder metal and/or refractory coated ferrous metal

Coatings of a powdered protective metallic material or refractory material and mixtures thereof are formed on a ferrous metal strip as a wet film dispersion in a resin binder composition of a synthetic organic resin and a volatile organic solvent compatible with said resin, and the coated strip is heated to effect curing said resin binder and forming a flexible non-tacky dry film. The metal strip having the cured dry film containing powdered protective metallic material can be subjected to varying heat treatments to provide a wide range of protective coatings having improved surface properties, including iron-protective metal diffusion alloy coatings, such as iron-aluminum diffusion alloy coatings having a surface concentration of aluminum between about 8 and about 10 wt. percent aluminum, which have improved high temperature oxidation resistance after being severely strained during fabrication at room temperature.

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

A process of making a one-side-only coated endless metal sheet in which a sheet initially having a protective metal coating, such as zinc, on both lateral surfaces thereof is subjected to an electrolytic treatment which removes the protective metal coating from only one side of the metal sheet by continuously passing the metal sheet through an electrolytic treating chamber containing as an electrolyte bath a strongly acidic aqueous solution, such as sulfuric acid, having a pH from about pH 0.1 to 2.0, and preferably about pH 1.0, or a strongly alkaline aqueous solution, such as sodium hydroxide, having a pH of at least about pH 11 and preferably above pH 11, with said metal sheet being guided between spaced anodic and cathodic electrodes immersed in said electrolyte bath so as to establish a cathodic current between said anodic electrode and the adjacent surface of said metal sheet which is made cathodic and establishing an anodic current from a second rectifier between said cathodic electrode and the adjacent surface of said metal sheet which is made anodic, and maintaining the anodic current at a current density level so as to maintain the surface of said metal sheet which is to remain coated completely cathodic and effects complete removal of said protective metal coating from the anodic surface during the period said sheet remains in said electrolytic treating chamber, and with the cathodic current maintained at a current density level below said anodic current density level but sufficiently high to neutralize the E.M.F. generated when the said protective metal coating is immersed in said electrolyte bath.

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Cedar Lake, IN, United States of America

Brian A Sok