Neutral Flux
Neutral welding flux is a SAW flux that is metallurgically largely inert and barely changes the alloy composition of the weld metal, independent of layer thickness. It is preferred for thick multi-pass welds.
Physical-Chemical Mechanism of Action
Neutral welding flux contains no additional metals or chemical additives that would alter the alloy of the weld metal. It stays metallurgically inert and does not react with the metals in the weld pool.
Metallurgical Relevance & Risks in Welding
Because neutral flux brings no additives, the weld metal alloy stays unchanged. This is especially important for thick-walled multi-pass welds, where a homogeneous alloy structure matters. Wrong selection or use of non-neutral fluxes can cause chemical reactions and imbalances in the weld pool, leading to porosity, cracking, and reduced mechanical properties of the weld metal.
Workshop Practice & Action Instructions
Use neutral welding flux for thick-walled multi-pass welds. Make sure the flux is dry and free of contaminants. A precise temperature of the weld pool is key to get a homogeneous alloy. If you have questions about selecting or handling neutral flux, check the manufacturer's instructions.