# US 9,125,243 B2 · System for electromagnetic pulse surface treatment

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- Number: US 9,125,243 B2
- Document ID: US9125243B2
- Status: Granted
- Kind: B2
- Application number: 13/537,270
- Filed: 2012-06-29
- Published: 2012-10-25
- Granted: 2015-09-01
- Earliest claimed: 2006-01-11
- Assignees: Gatekey Engineering, Inc.
- Applicants: James R. Dydo; Sergei P. Yushanov
- Inventors: James R. Dydo; Sergei P. Yushanov
- Web page: https://patentgrep.com/patent/US9125243B2

## 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

An electromagnetic pulse surface treatment system for treating a work piece, having a bearing surface and a working surface, with a single electromagnetic pulse, comprising:
an electromagnetic pulse generator having a power supply and a capacitor,
wherein the electromagnetic pulse generator produces a current pulse having a current pulse duration;
an electromagnetic pulse tool in electrical communication with the electromagnetic pulse generator, wherein the electromagnetic pulse tool has a tool face and the tool face has a tool face perimeter, for forming and directing the single electromagnetic pulse toward the working surface; and
a controller to control operation of the electromagnetic pulse generator to generate the current pulse which travels to the electromagnetic pulse tool such that the single electromagnetic pulse emanates from the electromagnetic pulse tool to produce an indentation and a residual compressive stress layer in the working surface with substantially no stress change in the bearing surface opposite the residual compressive stress layer, wherein the tool face produces the indentation entirely below an untreated surface and free of pile-up above the level of the untreated surface along a perimeter of the indentation, and wherein the indentation is free of sharp transitions and comprises only smooth and continuous surfaces having radii greater than 1 millimeter and an indentation depth of less than 0.5 millimeter.

### Claim 2 (depends on 1)

The system of claim 1, wherein the controller further includes a sensor to measure the stress at the bearing surface opposite the residual compressive stress layer to ensure the stress does exceed the yield strength of the work piece.

### Claim 3 (depends on 1)

The system of claim 1, wherein the controller further includes an indentation depth sensor to measure an indentation depth upon creation of the indentation, and the controller compares the measured indentation depth to a target depth and adjusts at least one parameter selected from the parameter group including a current pulse magnitude, a current pulse duration, and a working distance from the working surface, in response to the comparison.

### Claim 4 (depends on 3)

The system of claim 3, wherein the controller controls the movement of the electromagnetic pulse tool and positions the tool face at the working distance from the working surface.

### Claim 5 (depends on 4)

The system of claim 4, wherein the at least one parameter selected from the parameter group is the working distance.

### Claim 6 (depends on 1)

The system of claim 1, further including at least a second electromagnetic pulse tool in electrical communication with the electromagnetic pulse generator wherein the second electromagnetic pulse tool has a second tool face and the second tool face has a second tool face perimeter, different from the tool face perimeter, for forming and directing a second electromagnetic pulse toward the working surface, wherein the controller controls operation of the electromagnetic pulse generator to generate a second current pulse which travels to the second electromagnetic pulse tool such that the second electromagnetic pulse emanates from the second electromagnetic pulse tool to produce a second indentation and a second residual compressive stress layer in the working surface with substantially no stress change in the bearing surface opposite the second residual compressive stress layer.

### Claim 7 (depends on 6)

The system of claim 6, wherein the controller controls the current pulse and the second current pulse so that the electromagnetic pulse and the second electromagnetic pulse occur simultaneously.

### Claim 8 (depends on 6)

The system of claim 6, wherein the controller controls the current pulse and the second current pulse so that the electromagnetic pulse and the second electromagnetic pulse are not simultaneous.

### Claim 9 (depends on 1)

The system of claim 1, wherein the controller includes at least one predetermined treatment pattern and automatically moves the electromagnetic pulse tool and discharges the electromagnetic pulse to achieve the predetermined treatment pattern.

### Claim 10 (depends on 1)

The system of claim 1, wherein the current pulse is 300 kA or less and the current pulse duration is 1 second or less.

### Claim 11 (depends on 10)

The system of claim 10, wherein the surface area of the tool face is no more than 4 mm2.

### Claim 12 (depends on 11)

The system of claim 11, wherein the tool face has a pulse concentration element to influence the shape of the electromagnetic pulse.

### Claim 13

An electromagnetic pulse surface treatment system for treating a work piece having a working surface, with an electromagnetic pulse, comprising:
an electromagnetic pulse generator having a power supply and a capacitor, wherein the electromagnetic pulse generator for generating a current pulse, wherein the current pulse has a current pulse duration;
a set of electromagnetic pulse tools including at least a first electromagnetic pulse tool and a second electromagnetic pulse tool, wherein:
the first electromagnetic pulse tool is configured for electrical communication with the electromagnetic pulse generator, wherein the first electromagnetic pulse tool has a first tool face and the first tool face has a first tool face perimeter, for forming and directing a first electromagnetic pulse toward the working surface, wherein a portion of the first tool face is a working distance of less than 1.0 millimeter from the working surface and no portion of the first tool face is in contact with the working surface; and
the second electromagnetic pulse tool is configured for electrical communication with the electromagnetic pulse generator, wherein the second electromagnetic pulse tool has a second tool face and the second tool face has a second tool face perimeter that is different than the first tool face perimeter, for forming and directing a second electromagnetic pulse toward the working surface, wherein a portion of the second tool face is a working distance of less than 1.0millimeter from the working surface and no portion of the second tool face is in contact with the working surface; and
a controller to control operation of the electromagnetic pulse generator to generate the current pulse which travels to either the first electromagnetic pulse tool or the second electromagnetic pulse tool such that the electromagnetic pulse emanates from the first electromagnetic pulse tool or the second electromagnetic pulse tool to produce an indentation and a residual compressive stress layer in the working surface with substantially no stress change in a surface opposite the residual compressive stress layer, and both the first tool face and the second tool face are configured to produce the indentation entirely below an untreated surface and free of pile-up above the level of the untreated surface alone a perimeter of the indentation, and wherein the indentation is free of sharp transitions and comprises only smooth and continuous surfaces having radii greater than 1 millimeter and an indentation depth of less than 0.5 millimeter.

### Claim 14 (depends on 13)

The system of claim 13, wherein a curvature of the second tool face is different than the first tool face.

### Claim 15 (depends on 13)

The system of claim 13, wherein the second tool face is asymmetric.

### Claim 16 (depends on 13)

The system of claim 13, wherein the first tool face has a pulse concentration element to influence the shape of the electromagnetic pulse, and the second tool face is flat.

### Claim 17 (depends on 13)

The system of claim 13, wherein the controller further includes an indentation depth sensor to measure an indentation depth upon creation of the indentation, and the controller compares the measured indentation depth to a target depth and adjusts at least one parameter selected from the parameter group including a current pulse magnitude, a current pulse duration, and a working distance from the working surface, in response to the comparison.

### Claim 18

An turbine airfoil electromagnetic pulse surface treatment system for treating a portion of a turbine airfoil having a working surface, with an electromagnetic pulse, comprising:
an electromagnetic pulse generator for generating a current pulse, wherein the current pulse has a current pulse duration;
an electromagnetic pulse tool in electrical communication with the electromagnetic pulse generator, wherein the electromagnetic pulse tool has a tool face and the tool face has a tool face perimeter, for forming and directing the electromagnetic pulse toward the working surface; a second electromagnetic pulse tool in electrical communication with the electromagnetic pulse generator, wherein the second electromagnetic pulse tool has a second tool face and the second tool face has a second tool face perimeter for forming and directing a second electromagnetic pulse toward a second working surface on an opposite side of the turbine airfoil from the working surface wherein the electromagnetic pulse tool and the second electromagnetic pulse tool are configured in substantially opposing orientation on opposite sides of the turbine airfoil to substantially cancel the forces generated by the electromagnetic pulses;
a controller to control operation of the electromagnetic pulse generator to generate (a) the current pulse which travels to the electromagnetic pulse tool such that the electromagnetic pulse emanates from the electromagnetic pulse tool to produce an indentation and a residual compressive stress layer in the working surface, and (b) a second current pulse, simultaneous with the current pulse, which travels to the second electromagnetic pulse tool such that the second electromagnetic pulse emanates from the second electromagnetic pulse tool to produce a second indentation and a second residual compressive stress layer in the working surface, wherein the tool face and the second tool face produce indentations entirely below an untreated surface and free of pile-up above the level of the untreated surface along a perimeter of the indentation, and wherein the indentations are free of sharp transitions and comprises only smooth and continuous surfaces having radii greater than 1 millimeter and an indentation depth of less than 0.5 millimeter.

### Claim 19 (depends on 18)

The system of claim 18, wherein the second tool face perimeter is different from the tool face perimeter.