If agglomerated welding flux isn't properly stored after drying, it's highly prone to secondary moisture absorption. Moist flux releases water vapor during welding, triggering welding defects such as weld porosity and hydrogen-induced cracks, which directly impair welding quality. Proper moisture-proof control after drying is therefore critical.
Secondary moisture absorption originates from the porous particle structure. After drying, internal pores of the flux stay dry and rapidly absorb moisture from humid ambient air. Re-moistening can occur even after short-term storage.
Environment control is the primary preventive measure. Dried flux should be transferred to constant-temperature drying ovens and kept at 100-150 ℃ for heat preservation instead of being stored at room temperature. Storage warehouses shall be dry and well-ventilated, with relative humidity kept below 60 %. Keep flux away from water vapor, rain and areas with ground moisture.
Next comes material transfer and sealing management. Minimize the exposure time of flux taken out of drying ovens in open air. Use sealed heat-preserving buckets for temporary storage and keep lids closed after each access. Take only the required amount each time and don't pour out large quantities of flux and leave it uncovered. Unfinished opened flux shall not be piled up randomly; re-seal it after cooling.
Besides, control stock turnover and follow the principle of drying according to actual demand. Avoid drying excessive batches at one time, so as to lower moisture-absorption risks caused by long-term post-drying storage. Conduct regular spot checks for moisture content. Once moisture is detected, re-dry the flux in accordance with specifications. Don't use damp flux directly for welding.
Standardized heat-preserving storage and sealing management can effectively stop secondary moisture absorption of agglomerated welding flux, stabilize weld formation and reduce risks of welding defects.
