# US 12,766,635 B2 · Method for manufacturing dissimilar material joint structure, and dissimilar material joint structure

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- Number: US 12,766,635 B2
- Document ID: US12766635B2
- Status: Granted
- Kind: B2
- Application number: 17/652,173
- Filed: 2022-02-23
- Published: 2022-06-09
- Granted: 2026-10-20
- Earliest claimed: 2019-08-27
- Assignees: Kobe Steel, Ltd.
- Applicants: Kobe Steel, Ltd.
- Inventors: Kyohei Maeda; Reiichi Suzuki
- Web page: https://patentgrep.com/patent/US12766635B2

## CPC

- B23K 26/323: involving parts made of dissimilar metallic material
- B23K 26/21: by welding
- F16B 5/08: by means of welds or the like (welding B23K)
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- F16B: DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING (couplings for transmitting rotation F16D)

## Abstract

A method for manufacturing a joint structure of dissimilar materials, the method includes: forming a low-temperature thermal spray coating on at least a part of a surface of an aluminum or aluminum alloy material by low-temperature thermal spraying a metal powder of at least one metal selected from the group consisting of pure iron, carbon steel, stainless steel, nickel, a nickel alloy, cobalt, and a cobalt alloy; overlapping the aluminum or aluminum alloy material and a steel material such that the low-temperature thermal spray coating and the steel material face each other; and joining the aluminum or aluminum alloy material and the steel material by laser a welding from a steel material side, in which the joining is performed under welding conditions in which a fusion zone is formed in the steel material, the low-temperature thermal spray coating, and the aluminum or aluminum alloy material.

## Claims

### Claim 1

A method for manufacturing a joint structure of dissimilar materials, the method comprising:
forming a low-temperature thermal spray coating on at least a part of a surface of an aluminum or aluminum alloy material by low-temperature thermal spraying a metal powder of at least one metal selected from the group consisting of pure iron, carbon steel, stainless steel, nickel, a nickel alloy, cobalt, and a cobalt alloy;
overlapping the aluminum or aluminum alloy material and a steel material such that the low-temperature thermal spray coating and the steel material face each other; and
joining the aluminum or aluminum alloy material and the steel material by a laser welding from a steel material side,
wherein the joining is performed under a welding condition in which a fusion zone is formed in the joint structure, the fusion zone comprising material from the steel material, the low-temperature thermal spray coating, and the aluminum or aluminum alloy material.

### Claim 2 (depends on 1)

The method for manufacturing a joint structure of dissimilar materials according to claim 1, wherein the joining is performed by laser radiation at least twice, and an amount of heat input in a second or subsequent laser radiation is less than an amount of heat input in a first laser radiation.

### Claim 3 (depends on 1)

The method of claim 1, wherein the fusion zone comprises aluminum in an amount of greater than 0 mass % to 5 mass %, based on a total mass of the fusion zone.

### Claim 4

A method for manufacturing a joint structure of dissimilar materials, the method comprising:
forming a low-temperature thermal spray coating on at least a part of a surface of an aluminum or aluminum alloy material by low-temperature thermal spraying a metal powder of at least one metal selected from the group consisting of pure iron, carbon steel, stainless steel, nickel, a nickel alloy, cobalt, and a cobalt alloy;
overlapping the aluminum or aluminum alloy material and a steel material such that the low-temperature thermal spray coating and the steel material face each other; and
joining the aluminum or aluminum alloy material and the steel material by a laser welding from a steel material side,
wherein the joining is performed by laser radiation at least twice under a condition in which the low-temperature thermal spray coating is partially penetrated, and an amount of heat input in a second or subsequent laser radiation is equal to or less than an amount of heat input in a first laser radiation, and
the joining forms a fusion zone in the joint structure that comprises material from the steel material, the low-temperature thermal spray coating, and the aluminum or aluminum alloy material.

### Claim 5 (depends on 4)

The method of claim 4, wherein the fusion zone comprises aluminum in an amount of greater than 0 mass % to 5 mass %, based on a total mass of the fusion zone.