Drawn Arc Stud Welding
Drawn Arc Stud Welding is generally used to weld large diameter fasteners to rougher and thicker base metals. Arc studs may be almost any shape and there are literally hundreds. However, they must have one end of the fastener designed for arc welding. Mild steel, stainless steel, and aluminum are applicable materials for arc stud welding.
- The weld gun is positioned over the base material and the main gun spring is partially compressed.
- The trigger is pressed and the stud lifts off the base, drawing an arc. The arc melts the end of the weld stud and the base material below. The arc shield (ferrule) concentrates the heat below the weld stud and contains the molten metal within the weld zone.
- The main spring plunges the weld stud down into the molten pool of metal in the base material. The cycle is completed in less than a second and the resulting weld bond develops the full strength of the fastener in the weld zone.
- The weld gun is withdrawn from the weld stud leaving and the ferrule. The ferrule is broken away and discarded.
Capacitor Discharge Stud Welding
Capacitor Discharge (CD) stud welding is generally used to weld smaller diameter fasteners to thin base metals. Since the entire weld cycle is completed in milliseconds, welds can be made without pronounced distortion, burn-through or reverse side discoloration. As long as one end of the fastener is designed for CD welding, CD studs can be manufactured in almost any shape.
- The weld gun and stud is positioned against the work plate. No ferrule is needed.
- Stored energy discharged through special weld “timing” tip and the stud starts downward.
- The stud is forced downward into the pool of molten metal.
- Metal solidifies and weld is completed in a split second.
Stud Welding Guidelines
- Set appropriate time for the weld base diameter.
- Set appropriate amperage for the weld base diameter.
- Ensure that the negative polarity is to the stud gun.
- Align accessories so they are centered and adjust legs so that 3/16″ to 1/4″ of the stud protrudes beyond the ferrule.
- Ensure a good, clean ground connection.
- Keep work surface relatively clean so that impurities don not affect weld.
- Keep studs and ferrules clean and dry.
- Test welds at the beginning of each shift or change in stud (AWS Bend Test).
- Check burn off (1/8″ to 3/16″ depending on stud diameter).
- Check weld fillet (360 degrees).
- Visually inspect all welds.
Difference Between ARC and Capacitor Discharge Style Studs
CD Fasteners generally utilize a specially engineered projection or tip at the weld base. It’s design configuration and length provide accurate welding time control, for consistently reproducible results.
The Stud Fastener held in the weld gun is applied firmly to the work surface under spring tension. Arc welding derives its source of energy from either DC rectifiers or motor-generator set. Its degree and intensity are automatically controlled by precision timing circuits.
Capacitor Weld Pins are available in 12-GA and 14-GA up to lengths of 6-inches as standard. Special lengths are available upon request.Capacitor Weld Studs are manufactured in minimum lengths of 1/4-inch up to 2-inch as standard. Other lengths are available upon request.Capacitor Weld Studs and Pins do not undergo any loss of length after welding.
Arc Studs are available from minimum lengths After Weld (AW) shown on individual specification sheets up to any length in increments of 1/8-inch. Please call one of our service representatives for specification sheets.All Arc Studs and Pins are reduced approximately 1/8-inch in length after welding for diameters up to 1/2-inch weld base diameter and approximately 3/16-inch for 5/8-inch weld base or larger.
What Process Should You Use?
Capacitor Discharge stud welding is a semi-automatic arc welding process. However, with CD welding, you have the ability to weld small diameter studs to very thin material. Since the entire weld cycle is completed in several milliseconds, welds can be made to thin sheets of metal without pronounced distortion, burn through or discoloration. The CD process allows stud welding of dissimilar metals.The CD process is commonly used in most sheet metal shops.
Arc stud welding allows almost any size or type of weld stud to be welded. Studs must be manufactured from weldable material and designed with a special arc stud tip. With the Arc process, you obtain a full fusion weld that becomes stronger than the stud itself. Arc stud welding is applicable to mild steel, stainless steel and aluminum.The Arc process is commonly used in most fabricating/structural steel shops.