Alloy 825 Stainless Steel Channels

Superior Sulfuric and Phosphoric Acid Resistance: Outstanding performance in H₂SO₄ (all concentrations up to moderate temperature), H₃PO₄, and mixed acids, making Alloy 825 the premier channel material for fertilizer and chemical processing facilities.

NACE MR0175 / ISO 15156 Compliant: Fully qualified for sour service (H₂S) up to 232°C (450°F), with documented HIC and SSC test reports available for oil and gas structural applications.

Excellent Chloride SCC Resistance: High nickel content (38-46%) provides outstanding resistance tochloride-induced SCC, outperforming all austenitic and duplex stainless steel grades.

Good Pitting and Crevice Corrosion Resistance: Molybdenum (2.5-3.5%) and chromium (19.5-23.5%) provide enhanced localized corrosion resistance in chloride-containing environments.

Titanium Stabilization: Titanium addition (0.6-1.2%) stabilizes the alloy against intergranular corrosion after welding, eliminating the need for post-weld heat treatment.

Good Weldability: Nickel-iron-chromium alloy offers good weldability with matching filler metals (ERNiCrMo-3 or ERNiCrMo-10). No preheat required for most applications.

Good High-Temperature Strength: Maintains excellent mechanical properties up to 540°C (1000°F) in non-oxidizing environments.

International Certifications: Channels can be certified by ABS, BV, DNV, LR, and comply with NORSOK M-650, NACE MR0175, and ASME standards.

Alloy 825 is a nickel-iron-chromium alloy with controlled additions of molybdenum and copper for enhanced corrosion resistance in reducing acid environments. The copper content (1.5-3.0%) provides exceptional resistance to sulfuric acid, while molybdenum (2.5-3.5%) enhances pitting resistance. Titanium stabilization (0.6-1.2%) prevents sensitization and intergranular corrosion after welding.

Comparison of Acid Resistance:

High-Temperature Tensile Properties (Typical Values):

Heat Treatment Condition:
All Alloy 825 channels are solution annealed at 925–1040°C followed by rapid cooling (water quenching or rapid air cooling). This heat treatment dissolves precipitated carbides, relieves internal stresses from rolling, restores optimum corrosion resistance and ductility, and ensures titanium stabilization is effective.

Critical Note: Alloy 825 is titanium-stabilized, which prevents sensitization and intergranular corrosion after welding. Unlike many stainless steels, Alloy 825 can be used in the as-welded condition without post-weld heat treatment for most corrosive environments.

Delivery Condition:
Channels are normally supplied in annealed and pickled condition, providing a clean, smooth surface and excellent corrosion resistance.

*Note: Weights calculated based on density 8.14 g/cm³. Custom sizes and longer lengths available upon request.*

Chemical Analysis: PMI verification for Ni (38-46%), Cr (19.5-23.5%), Mo (2.5-3.5%), Cu (1.5-3.0%), Ti (0.6-1.2%).

Intergranular Corrosion Test: ASTM G28 – validates resistance to intergranular corrosion (mandatory for stabilized grades).

Mechanical Testing: Tensile (≥585 MPa), yield (≥240 MPa), elongation (≥30%), hardness (≤200 HBW).

Dimensional Inspection: Web height, flange width, thickness, squareness, straightness, length.

Surface Inspection: Visual check for surface defects, cracks, and consistency.

Ultrasonic Testing (UT): Upon request.

Sour Service Qualification (upon request): HIC per NACE TM0284, SSC per NACE TM0177.

Third-Party Inspection: SGS, BV, DNV, TUV, LR, ABS available.

Sulfuric Acid Plants: Structural supports for acid coolers, heat exchanger platforms, acid storage tank support frames, piping rack structures in acid handling areas.

Phosphoric Acid Production: Evaporator structural frameworks, reaction vessel supports, agitator platforms, fertilizer storage building structures.

Pickling Plants (Stainless Steel): Pickling tank support structures, acid recovery system platforms, rinse tank framing, steel mill pickling line structures.

Oil & Gas Sour Service: Amine unit structural supports, sour water stripper platforms, glycol regeneration skid frames (NACE MR0175 compliant).

Offshore Chemical Injection: Methanol injection skid frames, glycol unit structural supports, chemical storage platform structures (ABS/BV/DNV/LR certified).

Chemical Processing (Aggressive): Reactor support structures, distillation column platforms, agitator framing, catalyst handling system supports.

Fertilizer Production: DAP/MAP production plant structures, granulation unit supports, conveyor structural framing.

Hydrometallurgy: Solvent extraction plant structural frames, electrowinning cell supports, pregnant leach solution tank structures.

Standard Packaging:

Bundles with steel straps and woven fabric wrapping

Plastic end protection for cut edges

Wooden pallets for export sea-worthy transport

Individual bundle labeling with grade, heat number, dimensions, quantity

Womic Steel's Shipping Strengths:

Direct cooperation with global shipowners – competitive freight rates

Professional loading and securing teams prevent bending and damage

Efficient document preparation (EN 10204 Type 3.1 MTR, PMI reports, ASTM G28 test reports, NACE certificates) minimizes customs delays

Continuous cargo tracking and after-sales follow-up

1. How does Alloy 825 compare to 316L for channel applications in acid service?
Alloy 825 offers significantly better resistance to sulfuric acid (H₂SO₄), phosphoric acid (H₃PO₄), and sour gas (H₂S). For acid plant structural supports and pickling line equipment where 316L would corrode rapidly, Alloy 825 is required.

2. Is Alloy 825 resistant to hydrochloric acid (HCl)?
Limited. Alloy 825 has fair resistance to dilute HCl but is not recommended for concentrated or aerated HCl. For hydrochloric acid service, consider Hastelloy C276.

3. Can Alloy 825 channels be welded without post-weld heat treatment?
Yes. Titanium stabilization prevents sensitization, and PWHT is not required for most corrosive environments. This is a major advantage for field fabrication.

4. Are Alloy 825 channels suitable for sour service (H₂S)?
Yes, with proper hardness control. Alloy 825 can be NACE MR0175 / ISO 15156 compliant for sour service. Full documentation including HIC/SSC test reports available upon request.

5. What is the maximum service temperature for Alloy 825 channels?
400°C (752°F) for general corrosive service. For sulfuric acid service specifically, limit to 150°C (302°F) depending on acid concentration.

Premier Acid Service Material: Excellent resistance to H₂SO₄, H₃PO₄, and sour gas – ideal for chemical processing and fertilizer production

NACE MR0175 / ISO 15156 Compliant: Full documentation for sour service applications

Titanium Stabilized: ASTM G28 intergranular corrosion tested – no PWHT required

Full Traceability: Heat number on each bundle – traceable to original mill certificate

Complete Size Range: From 75mm to 250mm web height – standard and custom sizes

Flexible Customization: Special lengths, surface finishes, and non-standard sizes available

Global Delivery: Exported to major chemical plants, acid facilities, and offshore projects worldwide

Website: www.womicstainless.com

E-mail: info@womicstainless.com

Tel / WhatsApp / WeChat:

Victor: +86 15575100681

Jack: +86 18390957568

Womic Steel – Your reliable partner for high‑quality stainless steel products, precision machined components, and custom solutions for corrosion‑resistant applications.

Stock Examples (Alloy 825 Stainless Steel Channels – Annealed & Pickled – Acid Service Grade):

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