As welds with a diameter > 5 mm and increasing welding times produce an increasingly larger and more turbulent weld pool, a ceramic ferrule must be used to protect the weld pool.
The ceramic ferrule supports the welding process by stabilising and confining the arc, shaping the molten metal and shielding it from the atmosphere. The shielding also slows down cooling, which has a beneficial effect on the weld microstructure.
The ceramic ferrule is slipped over the stud before welding and removed by breaking it off after solidification. Its main components are magnesium aluminium silicate and aluminium oxides, and it is characterised by its high temperature and thermal shock resistance. As your system supplier, we select the right ceramic ferrule for you. This means we always supply you with the best matching combination of ceramic ferrule and stud.
The ceramic ferrule is highly suitable for use on construction sites, as it can usually be welded with lightweight stud welding equipment and no heavy, cumbersome gas cylinders get in the way. It also prevents arc blow caused by environmental influences such as wind.
The ceramic ferrule process works as follows:
First, the ceramic ferrule is placed on the ferrule holder directly at the stud. Both are then placed on the workpiece together. To start the process, the stud is lifted off the workpiece with a low current and a pilot arc. After a short "holding time", the main arc, which actually melts the materials, is ignited. The ceramic ferrule confines the arc and prevents arc blow and dripping.
Throughout the welding process, the stud is thus lifted off the workpiece within the set welding time and then plunged back into the molten pool of the workpiece. This is where the stud joins the workpiece. Finally, the ceramic ferrule is broken off with very little effort.
The result is a firmly welded stud. The graphic shown here illustrates the welding process schematically.
