Drawn-arc stud welding with ceramic ferrule
Our welding technology explained in detail
The process “Drawn arc stud welding” is used for studs of an approximate diameter of 3 to 25 mm, welding current up to 3.000 A and welding times up to 3.000 ms.
In general, the positive pole of the power-source is connected to the workpiece.
The stud will be inserted into the chuck of the stud welding gun and positioned onto the workpiece, possibly by adding a ceramic ferrule.
Initiating the welding process: by means of a lifting mechanism, the stud will be lifted and at first an auxiliary arc (pilot arc) of a low current will be drawn. Then the main arc will be drawn between the tip of the stud and the workpiece.
The main arc of a high amperage must be adjusted to the diameter of the stud.
The cross sectional area of the stud and the opposite workpiece a partially melting.
After the lapse of the adjusted welding time, the stud is moved towards the work piece and both melting zones join tightly.
The power-source turns off, the melting zone solidifies and cools down.
If a ceramic ferrules was used, it will be removed afterwords.
| Operation | Stud welding with ceramic ferrule |
|---|---|
| Minimum sheet thickness t | 1/4 d |
| Maximum stud diameter d for welding from different positions | 25 ↓ 16 ← 20 ↑ |
| Suitable surface conditions¹) | bright metal, rolling skin, primer suitable for welding, surface rust, thin layer of oil |
| Unsuitable surface conditions¹) | hot-dip galvanising, loose layers of scaling, heavily corroded, protective coating |
| Common applications | studs with more than 8 mm ø in steel and boiler construction, and shipbuilding, on surfaces only coarsely cleaned, deep penetration, suitable for field welding |
¹) Here, we can give only general hints without any commitment or warranty on our part. The conditions must be tested in each individual case. Basically, a higher degree of surface cleanliness is required for shorter welding times. The best results are always achieved on bright metal surfaces.
