National Steel Corporation

Weirton Steel Corporation

Lowell W Austin

John R Smith

William D Bingle

Richard A Bird

John A Sinsel

William T Saunders

Tony Georgetti

Eugene J Chelen

Leslie D McGraw

Glenn W Bush

John L Swanson

James O Stoddart

Ralph Wilkerson

Edwin J Smith

Methods and apparatus enabling simultaneous electrolytic tinplating of bottom and top surfaces of continuous-strip flat-rolled steel substrate while moving in the direction of its length, are disclosed. Both surfaces are plated in a first cell of a multi-cell horizontally-oriented tinplating line. The stannous ion plating source and the source of electrical power, for each surface, differ. Tin pellets for an upper surface anode are confined in a solution-permeable material confined, within an electrically-conductive lining. Dissolution of surface iron from the steel strip is substantially eliminated, improving the stannous ion plating solution quality, eliminating requirements for harmful additives, and increasing the variety of electrolytically tinplated continuous-strip steel products and processes.

Electrolytic tinplating of steel substrate and apparatus

A new combination of steel strip electrolytic plating process steps which eliminate iron ion dissolution from continuous-strip steel substrate into chemically-corrosive plating solutions, such as Halogen-bath or methylsulphonic acid plating solutions, of horizontal passline electrolytic tin plating means which plate a single strip surface at a time. The previous use of a cyanide in Halogen-bath tin plating operations which formed a hazardous precipitant (prussian blue) is eliminated by eliminating iron ion dissolution from the steel strip substrate. And conversion of stannous ions to stannic ions, which formed additional Halogen-bath precipitant, is substantially eliminated. Also, new electrolytic plated product, with improved corrosion-prevention characteristics, is provided in which a flat-rolled steel substrate strike-coat of tin and/or nickel is plated simultaneously with electrolytic pickling of such cleansed substrate; pickle-plating is carried out prior to finish-surface electrolytic tin plating in such a horizontal passline electrolytic tin plating means.

Electrolytic plating of steel substrate

Stannous electrolytic tinplating baths utilized in flat-rolled steel tinplating operations contain non-filterable lead in solution at undesirable levels because of the lead content of commercially available tin anode materials. As taught herein, lead in the electrolyte is controllably incapacitated for deposition with the tin by chemical treatment of the bath which establishes, in solid phase, an insoluble bivalent metal compound having an affinity for lead which is adsorbed. In a preferred halogen-system embodiment, calcium fluoride presents an extended surface area for adhesion of lead and not only incapacitates lead in the bath for deposition purposes but also enables separation of such adsorbed lead from the plating bath as part of sludge removal. Quantitatively increasing, within an established range, the concentration of such a lead-absorbent solid-phase bivalent metal compound in the plating bath quantitatively decreases the percent by weight of lead deposited as part of the tin plating on the substrate.

Electrolytic tinplating and product

Drawn and ironed can bodies are formed from cold rolled steel sheet having a thin coating of a nickel-zinc alloy electroplated thereon by drawing the coated steel into a cup and ironing the sidewall of the cup on a mandrel by passing it through a toolpack comprising a plurality of ironing rings each including a generally conical lead-in surface having an angle relative to the axis of the mandrel within the range of 6.degree. to 81/2.degree. and a substantially cylindrical land extending no more than about 0.025 inches in the axial direction of the toolpack through the rings. The diameter of the land on successive ironing rings is progressively smaller in the direction of movement of the can through the toolpack, with the diameter of the final ironing ring being such as to reduce the sidewall of the cup to about one half its original thickness. The length of the land of the final ironing ring may be less than that of the previous ironing rings and preferably is within the range of 0.003 to 0.007 inches.

Method of forming D&I cans from coated steel

An improved sheet steel suitable for the production of containers and the like has a thin composite coating of nickel and zinc plated on both sides thereof. The steel substrate may be flat rolled blackplate and the composite nickel-zinc coating may be plated thereon by drawing a running length or strip of the steel through a nickel electroplating bath to which has been added the necessary concentration of zinc, and electrodepositing the two coating metals simultaneously and in the desired proportions. The coated steel sheet is particularly useful in forming drawn and ironed cans although it may be used for other purposes.

Nickel-zinc alloy coated drawn and ironed can

An electroplating process is disclosed for coating metal strip or sheet with a nickel-zinc alloy comprising at least 80% nickel. Steel sheet coated with the alloy exhibits excellent weldability.

Process of electroplating a nickel-zinc alloy on steel strip

Process for forming a drawn and ironed container

Nickel-zinc alloy coated steel sheet

A lead cathode which is immune to plating zinc on its surface when used in an electrolytic galvanizing solution.

Nonplating cathode and method for producing same

A cathode, particularly a lead cathode, which is immune to plating zinc on its surface when used in an electrolytic galvanizing solution. The method of producing such a cathode which comprises placing the lead cathode in an electrolytic solution containing zinc ions, electrolytically forming a light zinc coating on the surface of the cathode, and removing the zinc coating from the surface of the cathode, preferably by interrupting the applied current for a sufficient period to permit the zinc coating to dissolve in the electrolytic solution.

An electrolytic process and a cathode structure for use in the process for treatment of an elongated strip of metal as the strip is passed between an anode immersed in an acidic anolyte solution and a cathode immersed in a basic catholyte solution separated from the anolyte solution by an ion-permeable membrane. The cathode structure includes means for directing a flow of the catholyte solution through a chamber enclosing a negatively-charged cathode plate to cool the structure and to remove hydrogen gas which is evolved on the active cathode surface to increase the efficiency of the electrolytic process.

Method of and apparatus for electrolytic treatment of metal

A method for producing galvanized metal sheet or strip material having a zinc coating on one side only. The method includes utilizing the strip as a bipolar electrode and electrolytically removing a zinc coating from one side of the strip while simultaneously depositing a substantially equivalent amount of zinc on the opposite side of the strip. The method is most economically performed with a steel strip having a differential coating of zinc.

Method of producing metal strip having a galvanized coating on one side

A method for producing galvanized metal sheet or strip material having a zinc coating on one side only. The method includes immersing a strip (zinc-coated on both sides) in an electrolyte and passing it between anode means and separate cathode means so as to remove a zinc coating from one side of the strip while simultaneously depositing a substantially equivalent amount of zinc on the opposite side of the strip. The cathode means is immersed in a separate caustic catholyte solution which is kept separate from the main electrolyte by an anion exchange membrane, supported at least partly within the electrolyte, so as to prevent migration of zinc ions from the main electrolyte to the catholyte and cathode means and the formation of a deposit on the cathode means. The method is most economically performed with a steel strip having a differential coating of zinc.

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Weirton, WV, United States of America

Lowell W Austin