# US 11,028,470 B2 · Method for heat-treating metal materials

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- Number: US 11,028,470 B2
- Document ID: US11028470B2
- Status: Granted
- Kind: B2
- Application number: 15/796,357
- Filed: 2017-10-27
- Published: 2018-08-02
- Granted: 2021-06-08
- Earliest claimed: 2017-01-27
- Assignees: Battelle Memorial Institute
- Applicants: Battelle Memorial Institute
- Inventors: Aashish Rohatgi; Saumyadeep Jana
- Web page: https://patentgrep.com/patent/US11028470B2

## CPC

- C22F 1/06: of magnesium or alloys based thereon
- C22F 1/002: {by rapid cooling or quenching; cooling agents used therefor}
- C22F 1/02: in inert or controlled atmosphere or vacuum (adjusting the composition of the atmosphere C21D1/76)
- C22F 1/043: of alloys with silicon as the next major constituent
- C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00)

## Abstract

A method for heat treating metal materials by passing electrical current through a metallic workpiece to heat the workpiece via Joule heating to a preselected temperature for a preselected period of time, based upon the formula I2×R×t, wherein I is current, R is resistance and t is time. The current may be a direct or an alternating one. Various configurations of the method are envisioned wherein multiple current inputs and outputs are attached to the metal material so as to selectively heat specific portions of the piece including irregular shapes and differing diameters.

## Claims

### Claim 1

A method for electrically heat treating an aluminum 319 alloy workpiece comprising the step of: pulsing electrical current directly through the workpiece using at least one current input to heat the workpiece via resistive heating to a temperature less than 450 degrees C. for no more than 1 hour, then aging the piece to produce a hardened material having a harness of at least 50 on the RB scale.

### Claim 2 (depends on 1)

The method of claim 1 wherein the current is direct current.

### Claim 3 (depends on 1)

The method of claim 1 wherein the current is alternating current.

### Claim 4 (depends on 1)

The method of claim 1 wherein the electrical heating is done in a specialty gas atmosphere.

### Claim 5 (depends on 4)

The method of claim 4 wherein the specialty gas atmosphere is an inert gas atmosphere.

### Claim 6 (depends on 4)

The method of claim 4 wherein the specialty gas atmosphere is an oxidizing atmosphere.

### Claim 7 (depends on 4)

The method of claim 4 wherein the specialty gas atmosphere includes a mixture of gases including at least one gas selected from the group consisting of methane, ammonia, nitrogen, oxygen, hydrogen, and cyanide.

### Claim 8 (depends on 1)

The method of claim 1 wherein the current cycles at differing magnitudes.

### Claim 9 (depends on 1)

The method of claim 1 wherein the metallic work piece is quenched in place while still connected to the electrical supply then re-heated by electrical current to a preselected temperature for subsequent treatment.

### Claim 10 (depends on 1)

The method of claim 1 wherein the work piece has a nonuniform three dimensional shape including a circular geometry.