# US 8,253,081 B2 · System and method for electromagnetic pulse surface treatment

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- Number: US 8,253,081 B2
- Document ID: US8253081B2
- Status: Granted
- Kind: B2
- Application number: 11/939,046
- Filed: 2007-11-13
- Published: 2008-03-13
- Granted: 2012-08-28
- Earliest claimed: 2006-01-11
- Assignees: Gatekey Engineering, Inc.
- Inventors: James R. Dydo; Sergei P. Yushanov
- Web page: https://patentgrep.com/patent/US8253081B2

## CPC

- H05B 6/101: {for local heating of metal pieces}
- C21D 7/06: by shot-peening or the like
- Y02P 10/25: Process efficiency
- Y10T 428/12993: Surface feature [e.g., rough, mirror]
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (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; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A system and method for electromagnetic surface treatment of a work piece has an electromagnetic pulse generator and an electromagnetic pulse tool. The work piece has a working surface. A current pulse generated by the electromagnetic pulse generator travels through the tool producing an electromagnetic pulse. The electromagnetic pulse interacts with the working surface causing an indentation to form. A residual compressive stress layer is also formed. The indentation has a smooth and continuous topography that is described by an indentation perimeter, an indentation transition region, an indentation sidewall, an impact transition region, and an impact region. The method may also simultaneously, or subsequently, form a second indentation which overlaps with the indentation. An inter-indentation overlap region is formed when the indentations overlap. The inter-indentation overlap region is smooth and continuous. Multiple treated surfaces may easily be formed on the working surface of the work piece.

## Claims

### Claim 1

A work piece (20), having a bearing surface (22) and a working surface (24) wherein the working surface (24) is treated by an electromagnetic pulse, comprising:
a treated surface (30) formed when the electromagnetic pulse strikes the working surface (24), wherein the treated surface (30) has:
(A) a residual compressive stress layer (600), whereby the residual compressive stress layer (600) is formed such that substantially no stress change occurs in the bearing surface (22) opposite the residual compressive stress layer (600), and
(B) an electromagnetic indentation (300) having:
(i) an indentation perimeter (310);
(ii) an indentation sidewall (330);
(iii) an indentation transition region (320) extending from the indentation perimeter (310) to the indentation sidewall (330), wherein the indentation transition region (320) is described by an indentation transition radius (322);
(iv) an impact region (350) formed at an indentation depth (360), wherein the indentation depth (360) is measured from an untreated surface (26) to the impact region (350); and
(v) an impact transition region (340) extending from the indentation sidewall (330) to the impact region (350), wherein the impact transition region (340) is described by an impact transition region radius (342), and the indentation transition region (320) and the impact transition region (340) are curvilinear.

### Claim 2 (depends on 1)

The work piece (20) of claim 1, wherein the indentation transition radius (322) and the impact transition region radius (342) are greater than 1 millimeter.

### Claim 3 (depends on 1)

The work piece (20) of claim 1, wherein the indentation transition radius (322) and the impact transition region radius (342) are greater than 10 millimeters.

### Claim 4 (depends on 1)

The work piece (20) of claim 1, further including:
a second indentation (400), having a second indentation perimeter (410), formed adjacent to the indentation (300) by the electromagnetic pulse such that an inter-indentation overlap region (500) is formed, wherein:
(A) the indentation perimeter (310) and the second indentation perimeter (410) overlap to form a treatment perimeter (32) surrounding the treated surface (30) and the residual compressive stress layer (600) is formed in the treated surface (30) with substantially no stress change in the bearing surface (22);
(B) the second indentation (400) has:
(i) a second indentation sidewall (430);
(ii) a second transition region (420) that extends from the second indentation perimeter (410) to the second indentation sidewall (430), wherein the second transition region (420) is described by a second indentation transition radius (422);
(iii) a second impact region (450) formed at a second indentation depth (460), wherein the second indentation depth (460) is measured from the untreated surface (26) to the second impact region (450); and
(iv) a second impact transition region (440) that extends from the second indentation sidewall (430) to the second impact region (450), wherein the second impact transition region (440) is described by a second impact transition region radius (442), and the second transition region (420) and the second impact transition region (440) are curvilinear; and
(C) the inter-indentation overlap region (500) has:
(i) an overlap sidewall (520);
(ii) an overlap impact transition region (510) that extends from the impact region (350) to the overlap sidewall (520), wherein the overlap impact transition region (510) is described by an overlap impact transition region radius (512);
(iii) an overlap working region (540) formed at an overlap depth (544), wherein the overlap working region (540) is described by an overlap radius (542) and the overlap depth (544) is measured from the untreated surface (26) to a nearest portion of the overlap working region (540);
(iv) an overlap transition region (530) that extends from the overlap sidewall (520) to the overlap working region (540), wherein the overlap transition region (530) is described by an overlap transition region radius (532);
(v) a second overlap sidewall (560);
(vi) a second overlap transition region (550) that extends from the overlap working region (540) to the second overlap sidewall (560), wherein the second overlap transition region (550) is described by a second overlap transition region radius (552); and
(vii) a second overlap impact transition region (570) that extends from the second impact region (450) to the second overlap sidewall (560), wherein the second overlap impact transition region (570) is described by a second overlap impact transition region radius (572), the overlap impact transition region (510), the overlap sidewall (520), the overlap transition region (530), the second overlap transition region (550), and the second overlap impact transition region (570) are curvilinear.

### Claim 5 (depends on 4)

The work piece (20) of claim 4, wherein the indentation transition radius (322), the impact transition region radius (342), the second indentation transition radius (422), the second impact transition region radius (442), the overlap impact transition region radius (512), the overlap transition region radius (532), the second overlap transition region radius (552), and the second overlap impact transition region radius (572) are greater than 1 millimeter.

### Claim 6 (depends on 4)

The work piece (20) of claim 4, wherein the indentation transition radius (322), the impact transition region radius (342), the second indentation transition radius (422), the second impact transition region radius (442), the overlap impact transition region radius (512), the overlap transition region radius (532), the second overlap transition region radius (552), and the second overlap impact transition region radius (572) are greater than 10 millimeters.

### Claim 7 (depends on 4)

The work piece (20) of claim 4, wherein the overlap radius (542) is greater than 1 millimeter.

### Claim 8 (depends on 4)

The work piece (20) of claim 4, wherein the indentation depth (360) is greater than the overlap depth (544), and the second indentation depth (460) is greater than the overlap depth (544).

### Claim 9 (depends on 4)

The work piece (20) of claim 4, wherein the inter-indentation overlap region (500), the indentation (300), and the second indentation (400) are formed such that no portion of the inter-indentation overlap region (500), no portion of the indentation (300), no portion of the second indentation (400), and no portions of the working surface (24) adjacent to the treated surface (30), project away from the bearing surface (22).

### Claim 10 (depends on 4)

The work piece (20) of claim 4, wherein the indentation (300) and the second indentation (400) are formed substantially simultaneously.