Application of ceramic backing in arc welding

摘要

There are different backings in welding technology. Fig. 1 provides an overview of the most common systems. The natural type of backing is a groove preparation with a root face. This must be dimensioned in such a way that it cannot be melted through when the open side is being welded but must not, on the other hand, be so high, that it does not become completely molten during the cap pass. Natural backing demands high precision in groove preparation and this can considerably increase the manufacturing cost of a welded construction. In addition, it cannot be used for a one-side welding. If the root gap is too large between the two components of the joint or a groove preparation which was totally unsuited to mechanical welding was chosen, passes with a manually guided welding torch must, under some circumstances, first be made to provide backing.