Applications

Fasteners smaller than 3/32 in. in diameter and bolts or unthreaded pins up to 1¼ in. in diameter can be successfully welded. Fastener lengths vary from ¼ to 40 in., depending upon end use. Fasteners may be made of mild steel, stainless steel, alloy steel, aluminum, brass, bronze, or magnesium. Welded stud fasteners may be used to replace studs normally secured by drilling and tapping, arc welding, resistance welding, or brazing. The studs may be placed, where required, without regard to clearances behind the plate, and may be secured to exposed surfaces after other assembly operations have been completed. The base metal must be weldable. Straight low-carbon steels or austenitic (300 Series) stainless steels, except free-machining grades, produce good weld results with normal techniques. Other steel alloys can be welded, but heat treatment may be required to develop full weld strength. Many aluminum, brass, and copper alloys can also be welded. Weld quality with special materials may have to be determined through testing of prototype samples. The most common fasteners used in electric-arc welding are made from low-carbon steels, with a minimum tensile strength of 60,000 psi and a minimum yield strength of 50,000 psi. Special high-strength fasteners, comparable in strength to SAE grade 5 bolts, are also available. Capacitor-discharge fasteners are generally made from C-1008 to C-1010 steels in the annealed condition. Tensile strengths are 40,000 to 50,000 psi. Austenitic stainless steel, magnesium-aluminum, silicon-aluminum, and other nonferrous fasteners are made most commonly from materials in the as-rolled condition. Fasteners for capacitor-discharge welding are most effectively used on flat or nearly flat surfaces. Since point contact is not needed for drawn-arc capacitor-discharge welding, fasteners can be welded to round or contoured surfaces. Electric-arc stud welding is adaptable to round or angled surfaces, since it depends on the ferrule for the formation