# US 5,384,165 A · Method and apparatus to galvanize a ferrous substrate

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,384,165 A
- Document ID: US5384165A
- Status: Granted
- Kind: A
- Application number: 08/075,327
- Filed: 1993-06-11
- Granted: 1995-01-24
- Earliest claimed: 1993-06-11
- Assignees: SMS Engineering, Inc.
- Inventors: Thomas A. Sellitto
- Web page: https://patentgrep.com/patent/US5384165A

## CPC

- C23C 24/106: {Coating with metal alloys or metal elements only}
- C23C 26/02: applying molten material to the substrate
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)

## Abstract

A ferrous strip is galvanized by establishing an electrostatic potential on the strip which is then submerged on a fluidized bed of powdered galvanizing material and then allowing the adhered galvanized powder to be carried by the strip to a reflow station. The reflow station heats the strip and galvanizing material to liquidity the galvanizing material and establish the necessary alloy interface on the ferrous strip. Thereafter, the strip passes to a cooling zone wherein the reflowed galvanizing material is solidified before contacting a roller to use to direct the strip to the exit of the galvanizing apparatus. The atmosphere within the galvanizing apparatus is remained inert through the use of nitrogen which is also used as the fluid medium for the suspension of the galvanizing powder in the fluidized bed.

## Claims

### Claim 1

The method of coating a ferrous substrate with zinc, said method including the steps of:
introducing said substrate to a coating chamber having an inert atmosphere therein;
electro-statically depositing a layer of zinc powder on said substrate;
liquefying the zinc powder on the substrate;
reflowing the liquid zinc on the substrate to create a zinc iron alloy interface; and
cooling the substrate and the reflowed zinc coating thereon below the liquidous temperature of the zinc in an inert atmosphere.

### Claim 2 (depends on 1)

The method of claim 1 wherein said electro-statically depositing includes passing said substrate in a fluidized bed of zinc powder.

### Claim 3 (depends on 1)

The method of claim 1 wherein the zinc powder of the fluidized bed is suspended in a fluid medium including nitrogen.

### Claim 4 (depends on 1)

The method of claim 1 wherein the zinc powder is within the range of 5 to 15 microns.

### Claim 5 (depends on 1)

The method of claim 1 wherein the zinc powder essentially consists of zinc and unavoidable impurities.

### Claim 6 (depends on 1)

The method of claim 1 wherein the zinc powder consists of zinc and aluminum.

### Claim 7 (depends on 1)

The method of claim 1 wherein the reflowed zinc coating has a thickness of between 0.1 ounce per square foot and 0.6 ounce per square foot of substrate.

### Claim 8 (depends on 1)

The method of claim 1 wherein said substrate is introduced to said coating chamber at a temperature of at least about 700.degree. F.

### Claim 9 (depends on 1)

The method of claim 1 wherein said electrostatic deposition includes establishing an electro potential between said substrate and said zinc of between at least 15,000 and 25,000 volts.

### Claim 10 (depends on 1)

The method of claim 1 wherein the inert atmosphere in said coating chamber is nitrogen.

### Claim 11

A method of coating a ferrous substrate with zinc, said method including the steps of:
introducing said substrate to a coating chamber having an inert atmosphere therein;
imparting an static electric charge potential between said substrate and a volume of zinc powder;
statically supporting a film of powdered zinc on the substrate in the coating chamber by immersing the charged substrate in a volume of zinc powder;
heating the zinc powder coating on the substrate to a liquid temperature of the zinc;
allowing the liquid zinc to reflow creating a zinc iron alloy interface; and
cooling the substrate in an inert atmosphere with the reflowed zinc coating thereon.