Alloy 33's Superior Performance in Harsh Acidic Environments

Alloy 33,W.Nr.1.4591,a high-performance nickel-based corrosion-resistant alloy, has emerged as a game-changer in industries handling aggressive nitric and hydrofluoric acid mixtures. Its unique composition—comprising 31-35% chromium, 30-33% nickel, and strategic additions of molybdenum, copper, and nitrogen—delivers unparalleled resistance to extreme chemical conditions.

Nitric Acid Resistance: A Tested Legacy

With the ability to withstand concentrations up to 160 g/L nitric acid, Alloy 33's high chromium content forms a dense Cr₂O₃ passive layer, effectively shielding the alloy from oxidation. Nitrogen enhances passivation film regeneration, maintaining stability even in pH=1 hydrochloric acid environments.

Hydrofluoric Acid Compatibility: Engineered for Safety

Alloy 33 exhibits exceptional tolerance to 30 g/L hydrofluoric acid, thanks to synergistic effects of molybdenum (1.6%) and copper (0.3-0.7%). These elements improve resistance in reducing acids and fluoride-containing media, making it the material of choice for mixed-acid pickling equipment.

Comprehensive Advantages for Demanding Applications

1.Pitting & Crevice Corrosion Resistance: PREN value exceeding 50 ensures reliability in chloride-rich settings, with critical pitting temperature above 80°C.

2.High-Temperature Stability: Oxidative film integrity persists at 1100°C, ideal for high-temperature mixed-acid processes.

3.Weldability & Process Adaptability: Post-weld corrosion resistance retention exceeds 95%, facilitating complex structural fabrication.

Practical Considerations

While Alloy 33's performance is proven, engineers should evaluate temperature, flow rate, and acid ratios to optimize corrosion rates. Current data confirms its suitability for 160 g/L nitric + 30 g/L hydrofluoric acid mixtures, offering a cost-effective alternative to C-276.

Applications Across Industries

●Chemical Processing: Reactors, heat exchangers, and storage tanks for sulfuric/nitric acid blends.

●Marine Engineering: Seawater desalination plants and offshore platforms resisting chloride-induced degradation.

●Phosphate Production: Evaporators handling wet-process phosphoric acid.

Conclusion

Alloy 33 redefines corrosion resistance in the most aggressive acid environments. Its balanced composition, coupled with mechanical strength and thermal stability, positions it as a sustainable solution for industries prioritizing longevity and safety. For projects involving nitric/hydrofluoric acid mixtures, Alloy 33 ensures operational efficiency while minimizing material replacement costs.

Supplier of Quality Nickel Alloy  Wudenalloy has focused on the production and manufacture of nickel alloys for more than ten years. We are a principal worldwide supplier of corrosion-resistant  alloys and other superalloy metals. We have a professional technical team and after-sales service, so we can offer high -quality Hastelloy, Incoloy, Inconel,  Monel, Duplex Stainless Steel, and other alloy material. These materials are available in wire, bar, sheet&plate, pipe&tube, flange, forging, and other forms to meet  the needs of our customers. 

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