Drawn Arc Stud Welding: How It Works & Applications
Explore the principles, welding parameters, common defects, and industrial applications of drawn arc stud welding. This technical guide covers structural steel connections, bridge construction, shipbuilding, and heavy fabrication.
What Is Drawn Arc Stud Welding?
Drawn arc stud welding is an arc-based joining process used to permanently attach metal studs to a metal workpiece. The stud is briefly lifted to establish an electric arc, which melts the stud tip and a localized area of the base metal. The stud is then plunged into the molten pool, where the metal solidifies to form a metallurgical weld. Depending on the application, ceramic ferrules or shielding gas may be used to protect the weld area.
How Drawn Arc Stud Welding Works: The 4-Stage Process
Stage 1: Stud Positioning & Ferrule Setup
The stud is secured in the welding gun chuck and positioned against the prepared workpiece. For conventional ferrule-shielded drawn arc welding, a correctly matched ceramic ferrule is fitted around the stud base. It helps shield the arc, contain molten metal, and shape the weld collar during the welding cycle.
Stage 2: Stud Lift & Arc Formation
When the welding cycle starts, the gun’s lifting mechanism raises the stud to create an arc gap. In systems that use a pilot arc, it is established before the main welding arc. The arc melts the stud tip and the adjacent area of the base metal, forming a molten weld pool.
Stage 3: Controlled Plunge
At the end of the programmed arc time, the lifting mechanism releases the stud, and the gun’s spring pressure drives it into the molten pool. The stud tip and base metal fuse as the welding current is switched off. Where a ceramic ferrule is used, it helps contain the molten metal and shape a consistent weld collar around the stud.
Stage 4: Solidification & Inspection
The weld metal solidifies around the stud while the gun is held steady. After cooling, the welding gun is removed and the ceramic ferrule, where used, is broken away. Inspect the weld collar, stud alignment, and visible surface condition against the applicable welding procedure and project acceptance criteria. Visual appearance alone does not confirm weld strength.
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Drawn Arc Stud Welding Applications
Drawn arc stud welding is widely used to attach shear connectors, threaded studs, and other weld studs to steel structures and fabricated components. Common applications include bridge construction, composite steel buildings, shipbuilding, and heavy industrial fabrication. The appropriate stud type and welding procedure depend on the materials and project requirements.
Bridge & Infrastructure
Headed shear studs are welded to steel bridge girders to connect the steel structure with concrete bridge decks in composite construction. Welding procedures and inspection requirements are determined by the project specifications.
Structural Steel Construction
Studs welded to structural steel beams provide shear connections for composite floor systems. These connections help steel beams and concrete slabs work together in commercial buildings, warehouses, and industrial structures.
Shipbuilding & Marine Fabrication
Drawn arc welding can attach suitable studs to steel plates and fabricated marine assemblies, providing fastening points for equipment mounting, onboard fixtures, and other applications requiring welded attachments.
Industrial Machinery & Fabrication
Weld studs provide fastening points on machinery frames, heavy steel components, and fabricated industrial assemblies. Stud sizes and welding parameters are selected according to material thickness, joint design, and application requirements.
Drawn Arc Stud Welding Parameters: Reference Chart
The following drawn arc stud welding parameter chart provides reference settings for carbon steel stud welding with ceramic ferrules. Welding current, welding time, lift height, and stud protrusion vary depending on stud diameter, material, equipment, and welding conditions. Use these values as preliminary guidance and verify the final settings through trial welds and the applicable welding procedure.
| Stud Size | Stud Protrusion (mm) | Lift Height (mm) | Welding Current (A) | Welding Time (ms) |
|---|---|---|---|---|
| M6 | 2.5–3.0 | 1.2 | 300–500 | 100–200 |
| M8 | 3.0–3.5 | 1.2 | 450–600 | 150–300 |
| M10 | 3.5–4.5 | 1.5 | 550–750 | 250–450 |
| M13 | 4.5–5.0 | 2 | 800–1,000 | 400–650 |
| M16 | 5.0–5.5 | 2.5 | 1,100–1,350 | 550–800 |
| M19 | 6.0–6.5 | 3 | 1,450–1,650 | 750–1,000 |
| M22 | 7.0–7.5 | 3.5 | 1,700–1,950 | 900–1,200 |
| M25 | 8.0–8.5 | 4.5 | 2,100–2,400 | 1,100–1,500 |
Technical Note: The values above are preliminary reference settings for drawn arc stud welding and are not a qualified welding procedure. Actual welding current, time, lift height, and stud protrusion depend on the stud design, material, welding equipment, and operating conditions. Confirm suitable settings through trial welds and the applicable inspection requirements before production.
Key Factors Affecting Drawn Arc Welding Parameters
Welding Current & Time: Current and arc duration control heat input. Settings should be selected according to stud size, material, equipment, and welding conditions.
Stud Protrusion: The length of the stud extending beyond the ferrule affects plunge travel and weld collar formation. Check the gun and ferrule setup before welding.
Lift Height: The distance the stud is lifted creates the arc gap. Incorrect lift settings can affect arc stability and weld fusion.
Weld Collar Inspection: A consistent weld collar supports visual assessment, but appearance alone cannot confirm joint strength. Follow the applicable inspection and testing requirements.
Common Drawn Arc Stud Welding Defects & Troubleshooting
Common drawn arc stud welding defects include porosity, undercut, excessive spatter, incomplete fusion, and uneven weld collars. These issues may result from surface contamination, incorrect welding parameters, ferrule condition, gun alignment, or magnetic arc blow. The troubleshooting chart below outlines typical symptoms, possible causes, and recommended checks to help improve weld quality.
| Weld Defect | Typical Appearance | Possible Causes | Recommended Checks |
|---|---|---|---|
| Porosity | Visible pinholes or small cavities in the weld collar. | Moist ceramic ferrules, surface contamination, or inadequate shielding. | Clean and dry the workpiece. Use dry, correctly sized ferrules. Review welding conditions and shielding where applicable. |
| Undercut | A groove in the base metal near the edge of the weld collar. | Magnetic arc blow, poor ferrule alignment, or unsuitable welding parameters. | Check stud centering and return-clamp placement. Verify current and time settings against the applicable welding procedure. |
| Excessive Spatter | Excess molten metal droplets around the stud and an irregular weld collar. | Excessive heat input, incorrect stud protrusion, or improper plunge movement. | Review welding current, time, protrusion, and gun movement. Confirm adjustments through trial welds. |
| Incomplete Fusion | Partial fusion between the stud and base metal; the defect may not be visible externally. | Insufficient heat input, contaminated surfaces, incorrect polarity, or inadequate plunge. | Clean the workpiece. Verify polarity, electrical connections, welding parameters, and plunge settings. Perform the required weld tests. |
| Uneven Weld Collar | An off-center weld collar with more metal on one side of the stud. | Gun misalignment, an incorrectly positioned ferrule, or magnetic arc blow. | Check gun perpendicularity and ferrule positioning. Review return-clamp locations and possible arc deflection. |
Practical Quality Checks for Drawn Arc Stud Welding
Bend Testing & Weld Acceptance: Where required, perform bend or other mechanical tests according to the applicable welding procedure and project acceptance criteria. Visual appearance or an arbitrary bend angle alone cannot confirm weld quality.
Magnetic Arc Blow Control: An off-center weld collar may indicate magnetic arc blow. Check the location of return clamps, cable routing, and welding near plate edges or corners. Adjust the setup as appropriate.
Ceramic Ferrule Condition: Use clean, dry, correctly sized ceramic ferrules. Check ferrule alignment before welding, and do not reuse damaged or previously used ferrules.
Drawn Arc Stud Welding FAQs
Find answers to common questions about drawn arc stud welding, including AWS D1.1 requirements, base metal thickness, material compatibility, ceramic ferrules, and welding parameters.
AWS D1.1 includes requirements for stud welding on structural steel. Compliance depends on the stud and base metal specifications, applicable welding procedure, required qualification or preproduction testing, and inspection criteria. Using the drawn arc process alone does not automatically guarantee code compliance.
There is no single minimum thickness suitable for every application. The required base metal thickness depends on stud diameter, weld base design, material properties, welding parameters, and project requirements. Verify the thickness against the applicable welding procedure and conduct trial welds when necessary.
Yes, certain stainless steel studs can be welded to carbon steel using suitable drawn arc procedures. However, the stud grade, base metal, corrosion requirements, and welding conditions must be considered. Material selection and weld quality should be verified for the intended application.
No. Ceramic ferrules are commonly used in conventional drawn arc stud welding to protect the weld area, contain molten metal, and help form the weld collar. Some drawn arc applications use shielding gas instead. The protection method depends on the stud material, welding equipment, and applicable procedure.
Yes, aluminum studs can be welded using suitable drawn arc equipment and welding procedures. Specialized aluminum studs, controlled welding parameters, and appropriate shielding, often involving argon, may be required. The most suitable welding process depends on the stud size, base material, and application requirements.
Welding current, welding time, lift height, and stud protrusion are selected according to the stud diameter, material, weld base design, equipment, and welding conditions. Reference charts provide starting points, but the final settings should be verified through trial welds and the applicable welding procedure.
