Water Treatment
Where Nickel Alloy Earns Its Place in Water Treatment
Industry Overview
Being straight with buyers: most of a municipal or industrial water treatment plant should not be built in nickel alloy. 304L/316L and duplex grades cover the bulk of filtration, distribution and structural piping, and GFRP covers much of the chemical dosing. TOKO ALLOY does not sell those materials, so we will not quote them. What we do supply is the narrow, clearly-defined set of duties where the chloride or oxidising load is high enough that stainless fails early: hypochlorite and chlorine-dioxide generation, high-chloride industrial effluent, and brackish or brine-side heat exchange.
Key Challenges
Hypochlorite and Chlorine Dioxide Generation
Electrochlorination cells and ClO₂ reactors run at high chloride with a strong oxidising potential — the specific combination that pits and crevice-corrodes 316L at welds and gaskets. Hastelloy C-276 and C-22 are the standard answer for these skids.
High-Chloride Industrial Effluent
Effluent from chemical, mining and power sites can carry chloride well above the 200–500 ppm range that stainless tolerates at elevated temperature. Above that, and above about 60°C, the pitting and SCC margins close and a nickel alloy becomes the cheaper lifecycle option.
Brackish and Brine-Side Heat Exchange
Concentrating brackish water in thermal or membrane brine concentrators produces exactly the hot, deaerated, high-TDS condition that defeats duplex. Monel 400 and Inconel 625 handle the tube side in these units.
Oxidising Disinfectant Contact Chambers
Injection quills, static mixers and the first metre of contact piping see the full undiluted disinfectant dose. This is the highest-attack location in the plant and the one place where a nickel alloy is usually cheaper than repeated replacement.
TOKO ALLOY Solutions
C-276 / C-22 Chlorination Skid Piping
ASTM B622/B619 small-bore pipe and B626 tube for electrochlorination, hypochlorite storage and ClO₂ generation. Selected for oxidising-chloride resistance, not for general corrosion duty.
Inconel 625 Brine Concentrator Tubing (N06625)
ASTM B704/B705 tube for brine-concentrator and crystalliser heat exchangers where TDS and temperature together exceed what duplex 2507 will hold long-term.
Monel 400 for Brackish and Marine Cooling (N04400)
ASTM B163 tube and B165 pipe for brackish-water and seawater-cooled exchangers — high resistance to flowing seawater and chloride SCC at moderate temperature.
Incoloy 825 for Acid-Dosed Effluent (N08825)
ASTM B423 pipe for neutralisation and acid-dosing lines in industrial effluent treatment, where sulfuric or phosphoric acid is present alongside chlorides.
Recommended Materials Water Treatment
View detailed chemical composition, mechanical properties, and corrosion resistance data for each recommended grade:
Related Products
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