JOINING PROCESS

• US 3,807,033 A
• Filed: 08/29/1972
• Issued: 04/30/1974
• Est. Priority Date: 12/14/1970
• Status: Expired due to Term

• Current Assignee: Heinz Schoer, Werner Schultze
• Original Assignee: Heinz Schoer, Werner Schultze
• Inventors: Schultze, Werner, Schoer, Heinz
• Primary Examiner(s): Overholser, J. Spencer
• Assistant Examiner(s): Shore, Ronald J.
• Application Number:
  US05/285,099
• Time in Patent Office: 609 Days
• Field of Search: 75/178A,178R,178AC,178AT,178AM,178AN 29/494,504
• US Class Current: 228/221
• CPC Class Codes: B23K 35/282 Zn as the principal constituent

Abstract

A process for the fluxless soldering of aluminum-containing workpieces in substantially non-oxidizing atmospheres is carried out with a solder which contains 2-45% by weight of Al and at least one additive from the group consisting of Bi Sr, Ba, Sb and Be, the balance being Zn. The additives Bi, Sr, Ba and Sb constitute 0.01-10% by weight and the additive Be constitutes 0.00001-1.0% by weight of the solder. These additives lower the viscosity and surface tension of the molten solder and also decrease the interfacial tension between the molten solder and the workpieces.

Claims

2. In a process as defined in claim 1, wherein said filler metal contains 0.002-0.1% by weight of Be.

3. In a process of brazing aluminum-containing workpieces, the step of brazing said workpieces with a filler metal consisting essentially of 26-45% by weight of Al, up to about 1% by weight of Mn, 0.00001-1.0% by weight of Be, and 0.01-10% by weight of at least one substance selected from the group consisting of Bi, Sr, Ba and Sb, the remainder being substantially Zn, said Bi, Sr, Ba, Sb and Be lowering the viscosity and surface tension of said filler metal in its molten state and substantially decreasing the interfacial tension between the molten filler metal and said workpieces, and said step being performed without a flux and in a substantially non-oxidizing atmosphere.

4. In a process as defined in claim 3, wherein said filler metal contains 0.05-2% by weight of said at least one substance.

5. In a process as defined in claim 3, wherein said filler metal contains 0.002-0.1% by weight of Be.

6. In a process as defined in claim 1, wherein said filler metal contains 32.73% by weight of Al, 0.09% by weight of Be, and 0.03% by weight of impurities.

7. In a process of soldering aluminum-containing workpieces, the step of soldering said workpieces with a solder consisting essentially of 4.18% by weight of Al, 0.06% by weight of Be, 0.86% by weight of Mn, and 0.10% by weight of impurities, the remainder being substantially Zn, said Be lowering the viscosity and surface tension of said solder in its molten state and substantially decreasing the interfacial tension between the molten solder and said workpieces.

8. In a process of soldering aluminum-containing workpieces, the step of soldering said workpieces with a solder consisting essentially of 4.55% by weight of Al, 0.16% by weight of Bi, 0.02% by weight of Be, and 0.08% by weight of impurities, the remainder being substantially Zn, said Be and Bi lowering the viscosity and surface tension of said solder in its molten state and substantially decreasing the interfacial tension between the molten solder and said workpieces.

9. In a process of brazing aluminum-containing workpieces, the step of brazing said workpieces with a brazing alloy consisting essentially of 39.88% by weight of Al, 0.06% by weight of Bi, 0.01% by weight of Be, 0.37% by weight of Mn, and 0.05% by weight of impurities, the remainder being substantially Zn, said Be and Bi lowering the viscosity and surface tension of said brazing alloy in its molten state and substantially decreasing the interfacial tension between the molten solder and said workpieces.