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AL 718

AL 718 Technical Data


Used for a variety of applications including brazing electronic vacuum tube assemblies.  Common base materials joined include copper, nickel, metalized ceramics, nickel-cobalt-iron, and carbide.  

Brazing Characteristics

AL 718 (or BAlSi-4) is a low melting general purpose aluminum alloy with a narrow freezing range. AL 718’s silicon content provides for increased fluidity and reduced shrinkage. AL 718 produces bright and almost smut free welds. Hot cracking is reduced when this alloy is used.

Properties of Brazed Joints

The properties of a brazed joint are dependent upon numerous factors including base metal properties, joint design, metallurgical interaction between the base metal and the filler metal. Joint clearances of 0.003-0.005 in. (.076-.127mm) per side are optimum for achieving highest joint strength. Joints with increased clearances can still produce adequate joint strengths depending on final operating conditions.


AL 718 alloy conforms to: Aluminum Association (AA) 4047, American Welding Society (AWS) A5.8/A5.8M BAlSi-4, Aerospace Material Specifications (AMS) 4185

Available Forms

Wire, strip, engineered preforms, specialty preforms per customer specification, powder and paste. 

Compare With

  • AMS: 4185
  • AWS: BAlSi-4
  • Lucas: Al 718
  • UNS: A94047


  • Brazing Temperature Range High: 1120 F / 604 C
  • Brazing Temperature Range Low: 1080 F / 582 C
  • Liquidus: 1080 F / 582 C
  • Solidus: 1070 F / 577 C



  • Al: 86.45%
  • Si: 12%
  • Fe: 0.8%
  • Cu: 0.3%
  • Zn: 0.2%
  • Mn: 0.15%
  • Mg: 0.1%

The information and recommendations contained in this publication have been provided without charge & compiled from sources believed to be reliable and to represent the best information available on the subject at the time of issue. No warranty, guarantee, or representation is made by the Prince and Izant Company, Inc. as to the absolute correctness or sufficiency of any representation contained in this and other publications; Prince and Izant Company, Inc. assumes no responsibility in connection therewith; nor can it be assumed that all acceptable safety measures are contained in this and other publications, or that other or additional measures may not be required under particular or exceptional conditions or circumstances. The company and product names referenced herein are for identification purposes only. All trademarks and registered trademarks are the property of their respective owners.

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