Chemical cleaning solutions used in the galvanizing process cannot remove weld flux and slag. Therefore, weld slag must be removed by grinding, abrasive blast cleaning, wire brush, flame-cleaning, or chipping.
In order for weld slag to develop, flux must melt from the flux-coated welding wire/stick, then deposit onto the weld area. Therefore, only welds performed with flux-coated wire or a flux blanket are susceptible to the formation of weld slag. Welds performed with bare wire are not susceptible to weld slag formation and will therefore not require abrasive cleaning for this specific purpose.
See Table 1 for a list of common weld processes and whether weld slag formation is of concern for each process.