Alloy 20 (UNS N08020) - ASTM B473 Bar, Pipe & Plate Supplier | Hangbo Alloy
Date: 2026年7月21日 Categories: All Products、News Views: 373
Hangbo Alloy Group provides high-performance Alloy 20 (Carpenter 20) products, including round bars, seamless tubes, and corrosion-resistant plates. Below is the technical profile for Alloy 20:
Detailed Introduction to Alloy 20
Alloy 20 (UNS N08020), also known as Carpenter 20, is an "austenitic" nickel-iron-chromium alloy developed specifically for maximum resistance to acid attack, especially sulfuric acid. It possesses excellent resistance to general corrosion, pitting, and crevice corrosion in chemicals containing chlorides and sulfuric, phosphoric, and nitric acids. It also contains niobium for stabilization against sensitization and resultant intergranular corrosion.
Key Standards: ASTM B473 (Bar), ASTM B463 (Plate), ASTM B729 (Seamless Pipe), DIN 2.4660.
Chemical Composition of Alloy 20 (UNS N08020)
| Element | Content (%) |
|---|---|
| Nickel (Ni) | 32.0 - 38.0 |
| Chromium (Cr) | 19.0 - 21.0 |
| Iron (Fe) | Remainder (29.9 - 44.0) |
| Molybdenum (Mo) | 2.0 - 3.0 |
| Copper (Cu) | 3.0 - 4.0 |
| Niobium (Nb) + Ta | 8*C - 1.00 |
| Manganese (Mn) | 2.0 max |
| Silicon (Si) | 1.0 max |
| Carbon (C) | 0.07 max |
Mechanical Properties (ASTM B473 / B463)
| Property | Value (Min) |
|---|---|
| Tensile Strength | 551 MPa (80 ksi) |
| Yield Strength (0.2% Offset) | 241 MPa (35 ksi) |
| Elongation | 30% |
| Hardness (Rockwell B) | 95 HRB max |
Material Characteristics
- Excellent Sulfuric Acid Resistance: Specifically designed to withstand sulfuric acid up to boiling temperatures in a wide range of concentrations.
- Intergranular Corrosion Resistance: Stabilization with niobium prevents carbide precipitation during welding.
- Chloride Resistance: Good resistance to chloride stress corrosion cracking, superior to standard 300-series stainless steels.
- Ease of Fabrication: Excellent fabricability and weldability using common industrial processes.
Common Applications of Alloy 20
- Chemical Processing: Production of sulfuric acid, solvents, explosives, and plastics.
- Pharmaceuticals: Piping and reactors for active ingredient synthesis.
- Food Processing: Equipment exposed to pickling liquors and cleaning agents.
- Petrochemical: Gasoline production and heat exchangers.
Pros & Cons of Alloy 20
| Pros | Cons |
|---|---|
| Unmatched performance in boiling sulfuric acid environments. | Higher cost than standard stainless steels (316L, 904L). |
| Great weldability without the need for post-weld heat treatment. | Lower overall strength compared to high-nickel superalloys. |
| Versatile across a broad range of inorganic acids. | Limited high-temperature creep strength above 500°C. |
Frequently Asked Questions (FAQ)
Q: Is Alloy 20 a stainless steel or a nickel alloy?
A: It is often categorized as a "super stainless steel" because of its high iron content (~35%), but its performance in aggressive acids places it among high-performance nickel alloys.
Q: Can Alloy 20 be used for marine applications?
A: Yes, it offers useful resistance to seawater, though alloys like Monel 400 or Inconel 625 are typically preferred for direct long-term immersion.
Internal Links:
904L Stainless Steel - High Corrosion Resistance
Incoloy 825 - Excellent Acid Resistance
Production Process
Our Alloy 20 is produced using **AOD (Argon Oxygen Decarburization)** or VIM melting to ensure precise control over chromium and nickel levels. Material is solution annealed at 1800-1850°F and water quenched to ensure maximum corrosion resistance.
Testing & Inspection
- Sulfuric Acid Test: Verification of corrosion rate in boiling H2SO4.
- Intergranular Corrosion Test: ASTM A262 Practice B or C.
- Mechanical Testing: Tensile and hardness checks.
- Dimensional Inspection: Strict tolerance control for precision piping.
Quality Control
We provide full MTC (Material Test Certificates) according to **EN 10204 3.1**, ensuring compliance with **ASTM B473 and ASME SB473** standards.
Product Forms & Standards Comparison
| Product Form | Main Standard | Typical Range |
|---|---|---|
| Round Bar | ASTM B473 | Φ3mm - Φ350mm |
| Seamless Pipe | ASTM B729 | 1/2" - 8" Sch 40/80 |
| Plate | ASTM B463 | T 2mm - 25mm |
