Alloy 20 (UNS N08020) Supplier: Bars, Pipes & Fittings for Sulfuric Acid | Shanghai Hangbo Alloy Group

Shanghai Hangbo Alloy Group Co., Ltd. is an ISO 9001:2015 certified manufacturer and global supplier of Alloy 20 (UNS N08020, W.Nr. 2.4660) round bars, seamless pipes, plates, and fittings — the standard “super stainless” choice for sulfuric acid and chloride service across the chemical, pharmaceutical, and food industries worldwide.

Quick Answer: What Is Alloy 20?

Alloy 20 (Carpenter 20) is a nickel-iron-chromium alloy (approx. 35% Ni, 20% Cr, 2.5% Mo, 3.5% Cu) stabilized with columbium. It was developed specifically for sulfuric acid service and offers excellent resistance to sulfuric acid over a wide range of concentrations and temperatures, plus strong resistance to chloride stress-corrosion cracking and pitting. It sits between stainless steel and nickel alloys in both performance and price.

Key standards: ASTM B473 (bar), ASTM B729 (seamless tube), ASTM B464 (welded pipe), ASTM B463 (plate), ASTM B462 (forgings).

Why Engineers Choose Alloy 20

• Sulfuric Acid Champion: Excellent across 20–80% H2SO4 concentrations at moderate temperatures
• Chloride SCC Resistance: High nickel content resists stress-corrosion cracking
• Pitting & Crevice Resistance: Mo + Cu additions improve localized corrosion performance
• Stabilized Chemistry: Columbium prevents sensitization during welding
• Broad Fabricability: Cast, forged, rolled, and welded with matching AWS ERNiCr-3 or ENiCrMo-3 fillers

Shanghai Hangbo Alloy Group: Product Forms & Manufacturing Process

Alloy 20 Round Bars

Manufacturing route: EAF → VIM/ESR → hot forging/rolling → solution annealing (1120–1170°C) → water quenching → peeling/grinding.

• Diameter range: 6 mm — 400 mm
• Standards: ASTM B473; fasteners and valve stock available
• QC: Spectral analysis, tensile, hardness, UT

Alloy 20 Seamless Pipes & Tubes

Manufacturing route: VIM/ESR billet → hot extrusion → cold pilgering → solution annealing → pickling → NDT.

• OD range: 6 mm — 219 mm | Wall: 0.5 mm — 20 mm
• Standards: ASTM B729 (seamless), ASTM B464 (welded)
• Testing: 100% hydrostatic + eddy current or ultrasonic

Plates, Fittings & Forgings

• Plates: ASTM B463, thickness 2–60 mm
• Fittings: Elbows, tees, reducers per ASTM B366 (WPNC20); flanges per B462

Chemical Composition (ASTM B729)

Nickel (Ni): 32.0–38.0

Chromium (Cr): 19.0–21.0

Molybdenum (Mo): 2.0–3.0

Copper (Cu): 3.0–4.0

Columbium (Cb): ≥ 8 × C — 1.0

Iron (Fe): Balance

Carbon (C): ≤ 0.07

Manganese (Mn): ≤ 2.0

Silicon (Si): ≤ 1.0

Mechanical Properties (Solution Annealed)

• Tensile Strength: ≥ 550 MPa (80 ksi)
• Yield Strength (0.2%): ≥ 240 MPa (35 ksi)
• Elongation: ≥ 30%
• Hardness: ≤ 217 HBW

Typical Applications by Industry

• Chemical Processing: Sulfuric acid piping, tanks, pumps, and heat exchangers
• Pharmaceutical: Reactors and processing equipment requiring high-purity corrosion resistance
• Food Processing: Fatty acid, edible oil, and salt-processing equipment
• Pollution Control: Scrubbers and waste-acid recovery systems
• Solvent Extraction: Copper and uranium processing mixer-settlers

Quality Assurance at Shanghai Hangbo Alloy Group

1. Raw material traceability: Full heat-number traceability from melt to finished product.
2. Spectral analysis (OES): Chemistry verified per ASTM on every heat.
3. Mechanical testing: Tensile, hardness, and intergranular corrosion tests (ASTM A262 on request).
4. NDT: Ultrasonic for bars; eddy current + hydrostatic for tubes.
5. Certification: MTC per EN 10204 3.1 / 3.2; third-party inspection on request.

Frequently Asked Questions (FAQ)

What concentrations of sulfuric acid can Alloy 20 handle?

Alloy 20 is generally excellent in 20–80% H2SO4 below about 50°C, and in many dilute and concentrated acid services; higher temperatures and azeotropic concentrations require 28, 31, or nickel alloys.

What is the difference between Alloy 20 and 316L stainless steel?

Alloy 20 contains roughly three times the nickel plus 2.5% Mo and 3.5% Cu, giving substantially better resistance to sulfuric acid and chloride SCC than 316L.

Does Shanghai Hangbo supply Alloy 20 fasteners and flanges?

Yes — bolts, studs, and flanges are available from stock or short production runs, with full MTC documentation.

Contact Shanghai Hangbo Alloy Group

Get a quote within 10 minutes.

Shanghai Hangbo Alloy Group Co., Ltd.

Website: www.nickel-alloy.com

WhatsApp / Phone: +86 15821512599

Email: vicky@hangboalloy.com

Founded 2012 | ISO 9001:2015 | Specializing in Nickel Alloys, Superalloys & Special Metals