8.3.1 Only neutral fluxes (as defined in AWS A5.17) are acceptable for pressure retaining welds or attachments welds to pressure retaining components. Active fluxes shall not be used.
8.3.2 Addition of principal alloying elements to the weld via the flux (other than to compensate for arc losses) is not permitted for pressure retaining welds or attachments welds to pressure retaining components. Alloy fluxes may be used for CRA weld overlay and metallic hard-facing.
8.3.3 Substantiating data shall be submitted for Owner review confirming that the flux-wire combination for welding with Nb-containing wire or strip (e.g. ER347, EB9, ERNiCrMo-3) has been specifically formulated to avoid the risk of hot cracking and tightly adherent slag (“tiger stripe”) deposits on the weld metal surface.
8.3.4 The use of composite cored wire or metal powder additions is acceptable for welding pressure retaining welds or attachments to pressure retaining components in carbon steel.
8.3.5 Flux that is not fused during welding may be re-cycled providing it is sieved to removed any slag impurities, re-processed in accordance with the manufacturer’s recommendation and is mixed with fresh flux (no more than 20% by volume of re-cycled flux) prior to welding.
8.3.6 Recrushed slag (as defined in AWS A5.17) shall not be used for pressure retaining welds or attachments welds to pressure retaining components.