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Hastelloy® G-30 Alloy — Superior Corrosion Resistance for Aggressive Environments

TIME: 2025-06-24 SOURCE: Ruisen

Hastelloy® G-30 is a high-performance nickel-based alloy engineered to withstand severe corrosive and high-temperature environments. Its advanced chemical composition and robust mechanical properties make it an ideal material for chemical processing, oil & gas, marine engineering, and other demanding industries. Ruisen proudly offers precision-cut and custom-fabricated G-30 alloy products tailored to your critical applications.


1. Chemical Composition & Microstructure

Element

Content (%)

Role

Ni

Balance

Matrix foundation

Cr

28.5–31.5

Forms a dense protective oxide layer; significantly improves resistance to oxidizing acids (e.g., nitric and phosphoric acid)

Mo

4.0–6.0

Enhances resistance to reducing acids (e.g., sulfuric acid)

W

1.5–4.0

Works synergistically with Mo for acid resistance

Cu

1.0–2.4

Improves performance in fluoride-containing media

C

≤ 0.03

Reduces risk of intergranular corrosion



2. Key Performance Benefits

Exceptional Corrosion Resistance

  • Strong Acid Environments: In wet-process phosphoric acid containing Cl⁻ and F⁻, G-30 exhibits a corrosion rate as low as 0.025–2.5 mm/year—2 to 10 times better than Alloy G-3 and Alloy 625. Outstanding resistance in nitric + hydrofluoric acid mixtures.

  • High-Temperature Stability: Performs reliably at 1000–1100°C with excellent oxidation resistance.

  • Stress Corrosion Cracking Resistance: Superior resistance to chloride-induced SCC, especially in marine and chloride-rich environments.

Outstanding Mechanical Properties

  • High Strength: Tensile strength of 760–870 MPa, yield strength of 345–415 MPa, with elongation of 40–45%.

  • Thermal Strength: Maintains mechanical integrity at elevated temperatures—outperforming conventional stainless steels.

Excellent Fabrication & Weldability

  • Formability: Supports both cold and hot working (stamping, bending, forging, rolling) with moderate work hardening.

  • Welding: Recommended processes include GTAW (TIG) and GMAW (MIG) with ERNiCrMo-11 filler metals. Avoid SAW (submerged arc welding) to minimize heat input. Post-weld solution annealing at 1177°C (air or water quench) restores corrosion resistance.


3. Typical Applications

Chemical Processing

  • Phosphoric Acid Production: Evaporators, reactors, and pipelines—particularly suited for fluoride-rich wet-process systems.

  • Acid Pickling Equipment: Ideal for nitric/hydrofluoric acid-based pickling tanks and heat exchangers.

  • Aggressive Media Handling: Tanks and reactors for sulfuric, nitric, and formic acid service.

Oil & Gas

  • Sour Gas Wells: Components exposed to H₂S and CO₂-rich environments.

  • Refinery Equipment: Reactors and separators operating under high pressure and temperature.

Marine Engineering

  • Seawater Systems: Desalination units and offshore platform piping, offering excellent chloride corrosion resistance.

  • Ship Components: Pumps, valves, and seawater-contacting parts.

Nuclear Industry

  • Waste Management: Storage containers and processing equipment for radioactive and corrosive materials.


4. Comparison with Other Alloys

Alloy

Key Strengths Compared to G-30

G-3

G-30 has higher Cr content (30% vs. 22%) — significantly better in fluoride-bearing phosphoric acid; improved weld HAZ corrosion resistance

C-276

G-30 excels in oxidizing acid resistance (e.g., nitric acid), while C-276 performs better in reducing acids (e.g., hydrochloric acid)

316L SS

G-30 offers far superior high-temperature strength and localized corrosion resistance (pitting, crevice)



5. Processing Notes

  • Work Hardening: Cold forming may induce stress; intermediate annealing is recommended.

  • Cutting Techniques: Use laser or waterjet cutting; avoid flame cutting to prevent surface oxidation.

  • Surface Preparation: Clean thoroughly before welding to eliminate oil and oxides and prevent weld defects.


6. Standards & Certifications

Hastelloy® G-30 complies with major international standards:

  • ASTM: B366 (fittings), B581 (bars), B619 (welded pipes)

  • Corrosion Standards: NACE MR0175 (for sour oil & gas environments)

  • Equivalent Grades:

    • UNS N06030 (ASTM)

    • DIN 2.4603 (Germany)

    • NS3404 (China)


Conclusion

With its high-chromium formulation and balanced alloying elements, Hastelloy® G-30 delivers unparalleled corrosion resistance and mechanical durability in extreme environments. Ruisen proudly supplies this premium alloy for mission-critical applications in chemical processing, energy, and marine sectors—ensuring long service life and performance reliability where it matters most.

For technical datasheets or project consultations, please contact Ruisen Special Steel.