Wire electrodes for submerged-arc weld surfacing

Because of the many types of wear encountered in practice, the wire electrodes employed for weld surfacing must withstand the respective surface stresses involved with a variety of different chemical compositions.

For submerged-arc weld surfacing with solid wire electrodes, two approaches are possible: On the one hand, alloyed electrodes can be employed with standard welding powders. On the other hand, unalloyed electrodes can be used with powders which up-alloy the weld metal. Since submerged-arc welding with wire electrodes results in deep penetration with increased dilution, a larger number of passes is necessary for weld surfacing. In order to ensure identical conditions for producing individual structural constituents with different wire electrodes, welding is generally performed at an intermediate-pass temperature. Submerged-arc wire electrodes, that is, their chemical composition, are selected in combination with a suitable welding powder. With due consideration of the appropriate welding data, the prerequisites are thus satisfied for the welding behaviour as well as for the mechanical properties of the weld metal. Basically, fused and agglomerated welding powders are available. Fused powders are characterised by greater homogeneity, low sensitivity to moisture, good storage properties, and high abrasion resistance. An essential advantage of agglomerated powders is the fact that comparatively low temperatures are necessary for their manufacture. Consequently, for instance, these powders can be added for improving the technological properties in welding of temperature-sensitive deoxidation and alloying components.