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US 10,240,222 B2Granted
Current schedule for optimized reaction metallurgical joining
AssigneeGM Global Technology Operations LLC
InventorsJames G. Schroth, Thomas A. Perry
Life of this patent
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Abstract
A method of joining a first metal workpiece substrate and a second metal workpiece substrate by way of reaction metallurgical joining involves passing a pulsating DC electrical current through the metal workpiece substrates and a reaction material disposed between confronting faying surfaces of the workpiece substrates. The electrical current comprises a plurality of current pulses that generally increase in applied current level.
Claims19
A method of joining a first metal workpiece substrate and a second metal workpiece substrate by way of reaction metallurgical joining, the method comprising:
- providing a first metal workpiece substrate and a second metal workpiece substrate, the first and second metal workpiece substrates being stacked in overlapping fashion such that a faying surface of the first metal workpiece substrate confronts a faying surface of the second metal workpiece substrate, and wherein a reaction material is disposed between the faying surface of the first metal workpiece substrate and the faying surface of the second metal workpiece substrate at a joining location, the reaction material having a liquidus temperature below both a solidus temperature of the first metal workpiece substrate and a solidus temperature of the second metal workpiece substrate;
- passing a pulsating DC electrical current through the reaction material to resistively heat the reaction material and cause the reaction material to at least partially melt into a molten reaction material that contacts both the faying surface of the first metal workpiece substrate and the faying surface of the second metal workpiece substrate, neither the first metal workpiece substrate nor the second metal workpiece substrate being melted during passage of the pulsating DC electrical current, and wherein the pulsating DC electrical current comprises a plurality of current pulses, each of which has a maximum attained current level, and wherein the plurality of electrical current pulses increase in applied current level such that at least 75% of the maximum attained current levels are contained within an amperage band defined by an upper amperage limit and a lower amperage limit, the upper amperage limit and the lower amperage limit having positive linear slopes and being parallel to each other so as to provide the amperage band with a bandwidth of between 2 kA and 6 kA;
- and
- pressing the first and second metal workpiece substrates together while the molten reaction material is present between the faying surfaces of the first and second metal workpiece substrates, the passing of the pulsating DC electrical current and the pressing together of the first and second metal workpiece substrates resulting in formation of a solid state metallurgical joint between the faying surfaces of the first and second workpiece substrates.
1 more element
A method of joining a first metal workpiece substrate and a second metal workpiece substrate by way of reaction metallurgical joining, the method comprising:
- stacking a first metal workpiece substrate and a second metal workpiece substrate such that a faying surface of the first metal workpiece substrate confronts a faying surface of the second metal workpiece substrate, and wherein a reaction material having a liquidus temperature below both a solidus temperature of the first metal workpiece substrate and a solidus temperature of the second metal workpiece substrate is disposed between the faying surfaces of the first and second metal workpiece substrates;
- passing a pulsating DC electrical current through the reaction material to resistively heat the reaction material to a temperature above a solidus temperature of the reaction material yet below the solidus temperature of the first metal workpiece substrate and the solidus temperature of the second metal workpiece substrate, the pulsating DC electrical current comprising a plurality of electrical current pulses, each of which has a maximum attained current level, and wherein the plurality of electrical current pulses increase in applied current level such that at least 75% of the maximum attained current levels are contained within an amperage band defined by an upper amperage limit and a lower amperage limit, the upper amperage limit and the lower amperage limit having positive linear slopes and being parallel to each other so as to provide the amperage band with a bandwidth of between 2 kA and 6 kA;
- and
- pressing the first and second metal workpiece substrates together at least during passage of the pulsating DC electrical current to form a solid state metallurgical joint between the faying surface of the first metal workpiece substrate and the faying surface of the second metal workpiece substrate.
1 more element
A method of joining a first metal workpiece substrate and a second metal workpiece substrate by way of reaction metallurgical joining, the method comprising:
- stacking a first metal workpiece substrate and a second metal workpiece substrate such that a faying surface of the first metal workpiece substrate confronts a faying surface of the second metal workpiece substrate, and wherein a reaction material having a liquidus temperature below both a solidus temperature of the first metal workpiece substrate and a solidus temperature of the second metal workpiece substrate is disposed between the faying surfaces of the first and second metal workpiece substrates;
- 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 in axial facing alignment with each other at a joining location;
- 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;
- and
- passing a pulsating DC electrical current between the first and second electrodes and through the reaction material to resistively heat the reaction material thereby causing the reaction material to melt without melting the first and second metal workpiece substrates, the pulsating DC electrical current comprising a plurality of current pulses, each of which has a maximum attained current level, and wherein the plurality of electrical current pulses generally increase in applied current level such that at least 75% of the maximum attained current levels are contained within an amperage band defined by an upper amperage limit and a lower amperage limit, the upper amperage limit and the lower amperage limit having positive linear slopes and being parallel to each other so as to provide the amperage band with a bandwidth of between 2 kA and 6 kA.
2 more elements
Dependencies are inferred from the claim text.