Reaction material pre-placement for reaction metallurgical joining

Patent metadata

Field	Value
Publication number	US-10036083-B2
Application number	US-201514789134-A
Country	US
Kind code	B2
Filing date	Jul 1, 2015
Priority date	Jul 8, 2014
Publication date	Jul 31, 2018
Grant date	Jul 31, 2018

Abstract

A method of pre-placing a reaction material onto a surface of a metal workpiece substrate involves the use of oscillating wire arc welding. The method involves depositing and adhering the reaction material from a consumable electrode rod. In doing so, the reaction material can be deposited at any time before the metal workpiece substrate is ready for joining by reaction metallurgical joining, and the size and shape of the reaction material deposit can be more easily controlled.

First claim

The invention claimed is:

1. A method of performing reaction metallurgical joining, the method comprising:
using oscillating wire arc welding to adhere a reaction material deposit onto a faying surface of a first metal workpiece substrate at a deposition site, the use of oscillating wire arc welding involving transferring a molten reaction material droplet from a leading tip end of a consumable reaction material electrode rod onto the faying surface and allowing the droplet to solidify into the reaction material deposit;
pressing the first metal workpiece substrate and a second metal workpiece substrate together such that the reaction material deposit contacts and extends between the faying surface of the first metal workpiece, onto which the reaction material deposit is adhered, and a confronting faying surface of the second metal workpiece; and
heating the reaction material deposit while the first and second metal workpiece substrates are being pressed together to melt the reaction material deposit between the confronting faying surfaces of the first metal workpiece substrate and the second metal workpiece substrate, neither the first metal workpiece substrate nor the second metal workpiece substrate being melted during heating of the reaction material deposit, and wherein pressing the first and second metal workpiece substrates together and heating the reaction material deposit results in a solid-state metallurgical joint being formed between the faying surfaces of the first and second metal workpiece substrates.

2. The method set forth in claim 1 , wherein the first metal workpiece substrate is composed of copper or a copper alloy, and wherein the second metal workpiece substrate is composed of copper or a copper alloy.

3. The method set forth in claim 2 , wherein each of the first metal workpiece substrate and the second metal workpiece substrate is a phase lead tab of an electric motor stator.

4. The method set forth in claim 2 , wherein the reaction material electrode rod comprises a Cu—Ag—P reaction material alloy.

5. The method set forth in claim 4 , wherein the Cu—Ag—P reaction material alloy contains, on a weight percent basis, 70%-95% copper, 2%-20% silver, and 3%-8% phosphorus.

6. The method set forth in claim 1 , wherein pressing the first metal workpiece substrate and a second metal workpiece substrate together comprises:
contacting the first metal workpiece substrate with a first electrode and contacting the second metal workpiece substrate with a second electrode, the first and second electrodes being axially facially aligned with each other and being positioned so that current will flow through the reaction material deposit when exchanged between the electrodes; and
applying a compressive force to the first and second metal workpiece substrates through the application of pressure by the first electrode and the second electrode on the first metal workpiece substrate and the second metal workpiece substrate, respectively.

7. The method set forth in 1 , wherein heating the reaction material deposit comprises:
passing an electric current through the reaction material deposit to resistively heat the reaction material deposit.

8. The method set forth in claim 1 , wherein using oscillating wire arc welding to adhere a reaction material deposit onto a faying surface of a first metal workpiece substrate comprises:
(a) bringing the leading tip end of the consumable reaction material electrode rod into contact with the faying surface of the first metal workpiece substrate;
(b) passing electric current through the consumable reaction material electrode rod while the leading tip end of the electrode rod is in contact with the faying surface;
(c) retracting the consumable reaction material electrode rod away from the faying surface of the first metal workpiece substrate to thereby strike an arc across a gap formed between the consumable reaction material electrode rod and the faying surface, the arc initiating melting of the leading tip end of the consumable reaction material electrode rod;
(d) protracting the consumable reaction material electrode rod forward to close the gap and bring the molten reaction material droplet that has formed on the leading tip end of the electrode rod into contact with the faying surface of the first metal workpiece substrate, the contact between the molten reaction material droplet and the faying surface extinguishing the arc; and
(e) retracting the consumable reaction material electrode rod away from the faying surface to transfer the molten reaction material droplet from the leading tip end of the electrode rod to the faying surface of the first metal workpiece substrate, the molten reaction material droplet transferred to the faying surface of the first metal workpiece substrate solidifying into the molten reaction material deposit.

9. The method set forth in claim 8 , wherein the electric current is passed at an initial level when the leading tip end of the consumable reaction material electrode rod is first brought into contact with the faying surface of the first metal workpiece substrate.

10. The method set forth in claim 9 , wherein the electric current is passed at an intermediate level when the consumable reaction material electrode rod is protracted toward the faying surface to bring the molten reaction material droplet into contact with the faying surface, the intermediate level of applied current being less than the initial level.

11. The method set forth in claim 10 , wherein the intermediate level of the electric current is 50% to 75% of the initial level.

12. The method set forth in claim 9 , wherein the electric current is passed at a short level once the molten reaction material droplet is brought into contact with the faying surface of the first metal workpiece substrate and the arc is extinguished, the short level being greater than the initial level.

13. The method set forth in claim 12 , wherein the short level of the electric current is 125% to 150% of the initial level.

14. The method set forth in claim 8 , wherein steps (a) through (e) are repeated at least once to increase the size of the molten material droplet on the faying surface of the first metal workpiece substrate.

15. The method set forth in claim 8 , wherein the consumable reaction material electrode rod has a positive polarity throughout steps (a) through (e).

16. A method comprising:
providing a first metal workpiece substrate having a faying surface;
performing a first oscillating wire arc welding cycle to transfer a molten reaction material droplet from a consumable reaction material electrode rod onto the faying surface of the first metal workpiece substrate, the first oscillating wire arc welding cycle comprising:
bringing a leading tip end of the consumable reaction material electrode rod into contact with the faying surface of the first metal workpiece substrate;
applying an electric current through the consumable reaction material electrode rod at an initial level while the leading tip end of the electrode rod is in contact with the faying surface;
retracting the consumable reaction material electrode rod away from the faying surface of the first metal workpiece substrate to thereby strike an arc across a gap formed between the consumable reaction material electrode rod and the faying surface, the arc melting the leading tip end of the consumable reaction material electrode rod to form the molten reaction material droplet;
applying the electric current through the consumable reaction material electrode rod at an intermediate level, which is less than the initial

Assignees

• Gm Global Tech Operations Llc

Inventors

• Schroth James G
• Perry Thomas A
• Zhou Chen

Classifications

• B23K20/165

  involving an exothermic reaction of the interposed material · CPC title

• B23K9/042

  Built-up welding on planar surfaces · CPC title

• C22C9/00 Primary

  Alloys based on copper · CPC title

• B23K35/302

  Cu as the principal constituent · CPC title

• B23K9/0008 Primary

  Welding without shielding means against the influence of the surrounding atmosphere · CPC title