Incoloy 20丨UNS N08020
Incoloy 20 (Alloy 20 / UNS N08020) is an austenitic nickel-iron-chromium alloy specifically developed for superior resistance to sulfuric acid and a wide range of corrosive chemical environments. With excellent resistance to pitting, crevice corrosion, and chloride stress corrosion cracking, Incoloy 20 is widely used in chemical processing, pharmaceutical, food processing, and petrochemical industries. J&A Alloy supplies Incoloy 20 in pipe, tube, plate, sheet, bar, flange, and fitting forms with global delivery and full material certification.
Incoloy 20 Supplier & Manufacturer
Incoloy 20, also known as Alloy 20 (UNS N08020), is a nickel-iron-chromium austenitic alloy specifically developed to provide outstanding corrosion resistance in sulfuric acid and other aggressive chemical environments. By combining nickel, chromium, molybdenum, and copper, the alloy offers excellent protection against sulfuric acid attack, chloride stress corrosion cracking, pitting corrosion, and crevice corrosion, making it a reliable choice for demanding industrial applications.
Compared with conventional stainless steels such as 304L and 316L, Incoloy 20 delivers significantly improved performance in corrosive process environments while maintaining good mechanical strength, weldability, and fabrication characteristics. It performs well in sulfuric acid, phosphoric acid, nitric acid, and various chloride-containing solutions, making it suitable for long-term service in chemical processing facilities.
Due to its excellent balance of corrosion resistance, strength, and cost-effectiveness, Incoloy 20 is widely used in chemical processing equipment, heat exchangers, storage tanks, reactors, piping systems, pharmaceutical manufacturing, and pollution control applications. J&A Alloy supplies Incoloy 20 in pipe, tube, plate, sheet, bar, flange, and fitting forms, with full material traceability and Mill Test Certificates (EN 10204 3.1) available upon request.
Key features of Incoloy 20
- Excellent resistance to sulfuric acid.
- Outstanding resistance to chloride stress corrosion cracking.
- Good resistance to pitting and crevice corrosion.
- Enhanced resistance to phosphoric and nitric acids.
- Excellent mechanical strength.
- Good weldability and fabrication performance.
- Suitable for both oxidizing and reducing environments.
- Available in a wide range of product forms.
- Complies with ASTM, ASME, and international standards.
- Widely accepted as a cost-effective alternative to higher-alloy nickel materials in many chemical applications.
Chemical Composition of Incoloy 20
| Element | Content (%) |
|---|---|
| Nickel (Ni) | 32.0 – 38.0 |
| Chromium (Cr) | 19.0 – 21.0 |
| Iron (Fe) | Balance |
| Molybdenum (Mo) | 2.0 – 3.0 |
| Copper (Cu) | 3.0 – 4.0 |
| Niobium (Cb+Ta) | 8 × C min – 1.0 max |
| Manganese (Mn) | ≤ 2.0 |
| Silicon (Si) | ≤ 1.0 |
| Carbon (C) | ≤ 0.07 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.035 |
Physical Properties of Incoloy 20
| Property | Value |
|---|---|
| Density | 8.08 g/cm³ |
| Melting Range | 1357 – 1430°C |
| Electrical Resistivity | 0.98 μΩ·m |
| Thermal Conductivity | 11.5 W/m·K |
| Specific Heat Capacity | 500 J/kg·K |
| Modulus of Elasticity | 200 GPa |
Mechanical Properties of Incoloy 20
| Property | Value |
|---|---|
| Tensile Strength | ≥ 620 MPa |
| Yield Strength (0.2% Offset) | ≥ 300 MPa |
| Elongation | ≥ 35% |
| Hardness | ≤ 95 HRB |
Corrosion Resistance
Incoloy 20 was specifically developed to combat sulfuric acid corrosion and remains one of the most widely used alloys for this purpose. The addition of copper significantly improves sulfuric acid resistance, while chromium and molybdenum enhance resistance to pitting and crevice corrosion.
The alloy performs exceptionally well in sulfuric acid concentrations commonly encountered in chemical processing industries. It also provides excellent resistance to phosphoric acid, nitric acid, chloride-containing environments, and various organic acids.
Compared with conventional stainless steels, Incoloy 20 offers superior resistance to chloride stress corrosion cracking, making it an excellent choice for aggressive industrial environments.
High Temperature Performance
| Property | Performance |
|---|---|
| Recommended Continuous Service Temperature | Up to approximately 540°C |
| Oxidation Resistance | Good |
| Thermal Stability | Good |
| Sulfidation Resistance | Moderate |
Available Forms
| Product Form | Availability |
|---|---|
| Pipe | Seamless / Welded |
| Tube | Seamless / Welded |
| Plate | Available |
| Sheet | Available |
| Bar | Round / Flat / Hex |
| Rod | Available |
| Flange | Available |
| Pipe Fittings | Available |
Applications of Incoloy 20
- Chemical processing equipment
- Sulfuric acid handling systems
- Phosphoric acid production
- Heat exchangers
- Pickling equipment
- Pharmaceutical processing
- Food processing equipment
- Storage tanks and reactors
- Petrochemical facilities
- Marine and offshore equipment
Incoloy 20 vs Other Alloys
| Property | Incoloy 20 | 316L | 904L | Hastelloy C276 |
|---|---|---|---|---|
| Sulfuric Acid Resistance | Excellent | Moderate | Very Good | Excellent |
| Chloride SCC Resistance | Excellent | Poor | Good | Excellent |
| Pitting Resistance | Good | Moderate | Very Good | Excellent |
| Cost | Medium | Low | Medium-High | High |
Welding & Fabrication
Incoloy 20 exhibits excellent weldability using GTAW (TIG), GMAW (MIG), SMAW and SAW processes.
Recommended filler metals include ER320LR and matching Alloy 20 consumables.
The alloy can be readily formed, machined and fabricated using conventional equipment designed for stainless steel and nickel alloys. Proper heat input control and post-weld cleaning are recommended to maintain optimum corrosion resistance.
Standards & Equivalent Grades
| Standard | Designation |
|---|---|
| UNS | N08020 |
| Werkstoff Number | 2.4660 |
| ASTM Pipe | B729 |
| ASTM Tube | B729 / B464 |
| ASTM Plate, Sheet & Strip | B463 |
| ASTM Bar & Rod | B473 |
| ASME | SB463 / SB473 / SB729 |
| Trade Name | Alloy 20 / Incoloy 20 |
Frequently Asked Questions
What is Incoloy 20 used for?
Incoloy 20 is widely used in chemical processing equipment, sulfuric acid handling systems, heat exchangers, reactors, storage tanks, piping systems, pharmaceutical manufacturing, and pollution control equipment where high corrosion resistance is required.
Is Incoloy 20 resistant to sulfuric acid?
Yes. Incoloy 20 was specifically developed for sulfuric acid service and provides excellent resistance across a wide range of concentrations and temperatures.
What is the difference between Incoloy 20 and 316L stainless steel?
Incoloy 20 offers significantly better resistance to sulfuric acid, chloride stress corrosion cracking, and aggressive chemical environments than 316L stainless steel, making it more suitable for severe corrosion applications.
What is the difference between Incoloy 20 and 904L?
Both alloys provide excellent corrosion resistance, but Incoloy 20 generally performs better in sulfuric acid environments and offers improved resistance to chloride stress corrosion cracking compared with 904L.
Is Alloy 20 the same as Incoloy 20?
Yes. Alloy 20 and Incoloy 20 refer to the same nickel-iron-chromium alloy designated as UNS N08020.
Can Incoloy 20 be welded?
Yes. Incoloy 20 has excellent weldability and can be welded using GTAW (TIG), GMAW (MIG), SMAW, and other conventional welding methods.
What is the UNS number of Incoloy 20?
The UNS designation for Incoloy 20 is UNS N08020.
What forms are available for Incoloy 20?
Incoloy 20 is available in pipe, tube, plate, sheet, bar, rod, flange, and fitting forms to meet a wide range of industrial requirements.
Which industries use Incoloy 20?
Incoloy 20 is commonly used in chemical processing, petrochemical, pharmaceutical, food processing, power generation, and pollution control industries.
Is Incoloy 20 suitable for chloride environments?
Yes. Due to its nickel content, Incoloy 20 offers excellent resistance to chloride stress corrosion cracking and performs well in chloride-containing process streams.
Why Choose J&A Alloy
- J&A Alloy specializes in high-performance nickel alloys and corrosion-resistant materials for demanding industrial applications.
- We provide strict quality control and full traceability for every order.
- Mill Test Certificates (EN 10204 3.1) are available upon request.
- Global shipping and flexible logistics solutions support customers worldwide.
- Custom manufacturing services are available for non-standard sizes and specifications.
- Our experienced technical team assists customers in selecting the most suitable alloy for their specific applications.
