The industry choice for weld metal overlay

Digester vessels are typically manufactured from carbon steel. Because of increased production expectations and environmentally driven process changes, these vessels suffer severe corrosion attack by cooking liquor. The AZZ | WSI Unifuse® vessel weld overlay technology was originally developed for the field installation of a fully fused, low dilution, corrosion-resistant cladding to mitigate this degradation process.

In continuous digesters, corrosion zones are easily identified with a periodic thickness mapping program. As critical wastage zones are identified, the Unifuse® vessel overlay process is used to deposit a 309 or 312 stainless steel deposit. Because of the large size and short turnaround windows required for continuous digester plant maintenance, the industry leading application production rates that are achieved using the AZZ | WSI process offer our clients the best possible solution.

Because of their more aggressive corrosion environment, batch digesters typically require the use of 312 stainless steel as a protective deposit. One major difference between the AZZ | WSI Unifuse® process and other welded approaches offered in the industry is our patented duplex stainless welding technology, which eliminates the solidification cracking found in conventional 312 weld deposits. 

Due to technical success and unparalleled return on investment, the industry chooses AZZ | WSI’s Unifuse® solution above all others. This has resulted in the largest installed base of weld metal overlay in the industry, and a solid reputation for safety, quality and overall value.