Besides screw joints or clip-on joints metallic anchoring systems are attached mainly by welding. For attaching anchors mainly 2 welding methods are in general use: manual welding with electrodes or wire (inert gas shielded arc welding) and semi-automated welding with stud welding units using the liftoff ignition method.

For the anchors themselves mostly heat-resistant alloys are used or those which are creep resistant at elevated temperatures. The support to which the anchoring system is welded is most frequently made from weldable carbon steel. This constellation is called a black-white joint. Black-black or white-white joints are found less often. We are offering in our supply programme the correct electrodes and wires for expert manual welding. We will be glad to assist you to choose the right electrode. Stud welding, or rather arc welding with lift-off ignition belongs among the arc pressure welding methods. From the various welding methods, stud welding with ferrules is practically the only method used for welding on fire resistance anchors. For this reason other methods are not discussed here.

For preparing the weld, the stud or anchor is inserted into the stud holder and the ferrule into the ferrule holder.The tip of the part to be welded protrudes from the ferrule by as much as it is desired to be immersed into the weld. The stud welding is carried out in four steps: The welding pistol is moved to touch the workpiece so that the ferrule touches it with its complete area (A). For the initiation of he welding process the stud / anchor is first lifted by 1 to 3 mm. At the same time the electric arc is ignited between the tip of the stud and the workpiece (B). The electric arc partially melts both the piece to be welded on and the workpiece.

After a time matched to the joint being welded, the stud is moved into the pool of molten metal on the work piece and the welding current is switched off (C). The welding zone cools down and the joint hardens; now the welding process is complete. Finally the ferrule is removed (D).The process parameters which have to be adjusted are the welding current, the welding time, the lift-off distance and the immersion distance.