THE DRAWN ARC STUD WELDING PROCESS.
|Stud tip touches workpiece.||Stud lifts off workpiece, electric arc is ignited.||Stud is plunged into welding pool. Material solidifies and stud is welded.|
Arc Stud Welding involves the same basic principles and metallurgical aspects as any other arc welding procedure, in that a controlled electric arc is used to melt the end of the stud or electrode and a portion of the base metal. The stud is thrust automatically into the molten metal and a high quality fusion weld is accomplished where the weld is stronger than the stud itself. Stud Welding is applicable to mild steel, stainless steel, and aluminum.
Welded fasteners or studs may be almost any size, shape, or type and there are literally hundreds, however they must be made of weldable materials and one end of the fastener must be designed for welding. Conventional DC welding machines of all types may be used, but special power units designed specifically for stud welding are also available.
The ARC stud weld can be visually inspected by observing the fillet at the base of the stud. The illustrations and comments below will assist you in visually judging the quality of the weld.
If after visual inspection the weld quality is still questionable, or specifications require, the welded stud can be submitted to additional testing, The following are suggested physical tests.
BEND TEST: (see illustrations) By striking the weld stud with a hammer, or by sliding a length of pipe over the weld stud, the stud can be bent a minimum of 30 degrees away from its axis, or until failure occurs. Satisfactory welded studs should exhibit a complete 90 degree bend without failure.
TORQUE TEST: The weld stud may be torqued with conventional torque testing equipment by applying torque until a predetermined torque or proof load is reached or until failure occurs.
TENSILE TEST: The weld stud may be tested with conventional tensile testing equipment until a predetermined load is reached or until failure occurs.
OTHER:The stud and weld can be submitted to other conventional forms of destructive or non-destructive testing as specifications may require.