West Conshohocken, PA: ASTM International, 2010, DOI 10.1520/A0449-10. 24. ASTM International. ASTM Standard A490, 2010 Standard Specifications for Structural Bolts, Alloy Steel, Heat Treated, relatively high temperatures, above 840°F (450°C), using al- loys of copper, silver, aluminum, silicon, or zinc. Of course, the metals to be joined must have a significantly higher melt- ing temperature. Metals successfully brazed include plain carbon and alloy steels, stainless steels, nickel alloys, copper, aluminum, and magnesium. Soldering is similar to brazing, except that it is performed at lower temperatures, less than 840°F (450°C). Several soldering alloys of lead-tin, tin-zinc, tin-silver, lead-silver, zinc-cadmium, zinc-aluminum, and others are used. Brazed joints are generally stronger than soldered joints due to the inherently higher strength of the brazing alloys. Most soldered joints are fabricated with in- terlocking lap joints to provide mechanical strength, and then the solder is used to hold the assembly together and possibly to provide sealing. Joints in piping and tubing are frequently soldered. Adhesives are seeing wide use. Versatility and ease of application are strong advantages of adhesives used in an array of products from toys and household appliances to automotive and aerospace structures. (See Internet sites 3 and 17.) Some types include the following: Acrylics: Used for many metals and plastics. Cyanoacrylates: Very fast curing; flow easily between well-mated surfaces. Epoxies: Good structural strength; joint is usually rigid. Some require two-part formulations. A large variety of formulations and properties are available. Anaerobics: Used for securing nuts and bolts and other joints with small clearances; cures in the absence of oxygen. Silicones: Flexible adhesive with good high-temperature performance (400°F, 200°C). Polyester hot melt: Good structural adhesive; easy to apply with special equipment. Polyurethane: Good bonding; provides a flexible joint. REFERENCES 1. ASTM International. ISO Standards Handbooks—Fasteners and Screw Threads—Volumes 1&2. West Conshohocken, PA: ASTM International, 2001. 2. ASTM International. Publication STP 587, Metric Mechanical Fasteners. West Conshohocken, PA: ASTM International, originally published 1975, updated 2011. 3. Barrett, R. T., and National Aeronautics and Space Administration (NASA). Fastener Design Manual. Seattle, WA: Create Space/Amazon.com, 2011. 4. Bickford, J. H. Introduction to the Design and Behavior of Bolted Joints: Non-Gasketed Joints. 4th ed. Boca Raton, FL: CRC Press, 2008. [See also Payne, Item 16.] 5. Bickford, J. H., and Sayed Nassar (eds). Handbook of Bolts and Bolted Joints. New York: Marcel Dekker, 1998. 6. Blake, Alexander. Design of Mechanical Joints. Boca Raton, FL: CRC Press, 1985. [Note: This is a reference book recommended by International Fasteners Institute.]
CHAPTER NINETEEN Fasteners 641 Ltd. and Interfast (USA). Engineering guide available on the website.
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