Lean duplex UNS S32304 welded pipes and tubes offer a useful balance of corrosion resistance, strength and reduced wall thickness. Also known as Grade 2304 or EN 1.4362, this duplex stainless steel contains about 23% chromium and 4% nickel with a low molybdenum content. Its pitting resistance is close to 316L, while the 400 MPa minimum yield strength is more than twice that of 316L, allowing thinner walls in many applications. Amardeep Steel supplies these pipes and tubes to ASTM A789, A790 and A928. Compare our SS 316L pipes and tubes and UNS S32205 duplex pipes and tubes, or browse all duplex steel pipes and tubes. Every order includes an EN 10204 3.1 mill test certificate and full heat traceability.
What Are UNS S32304 Welded Pipes and Tubes?
S32304 is a lean duplex stainless steel with a mixed austenite and ferrite structure. The ferrite gives strength and resistance to chloride stress corrosion cracking, and the low molybdenum keeps cost below 2205. Like other duplex grades, it is kept below about 300°C in service to avoid 475°C embrittlement.
How Welded S32304 Is Made
Strip is formed and welded along a longitudinal seam with nitrogen bearing shielding gas to keep the austenite and ferrite balance in the weld. ASTM A789 and A790 then require the tube or pipe to be solution annealed and rapidly cooled. Large bores are made as EFW pipe with filler to ASTM A928, in classes that set radiography and pressure test.
S32304 Welded Pipe Specifications
Parameter | Details |
|---|---|
Grade | Lean Duplex 2304 |
UNS | S32304 |
Standards | ASTM A789 / ASME SA789 (tube), ASTM A790 / ASME SA790 (pipe), ASTM A928 (EFW pipe), EN 10217-7 (1.4362) |
Type | Welded tube and pipe, longitudinal seam, TIG or plasma welded; larger bores as EFW pipe with filler |
Size Range | Tube and pipe sizes to the purchase specification |
Schedules | SCH 5S, 10S, 40S, 80S and specified wall |
Length | Random, fixed and cut lengths |
Ends | Plain end and bevelled end |
Heat Treatment | Solution annealed and rapidly cooled after welding |
Test Certificate | EN 10204 3.1, with 3.2 available on request |
Lean Duplex UNS S32304 Welded Pipes & Tubes Chemical Composition
Element | Content (%) |
|---|---|
Carbon (C) | 0.030 max |
Manganese (Mn) | 2.50 max |
Phosphorus (P) | 0.040 max |
Sulfur (S) | 0.040 max |
Silicon (Si) | 1.00 max |
Nickel (Ni) | 3.0 to 5.5 |
Chromium (Cr) | 21.5 to 24.5 |
Molybdenum (Mo) | 0.05 to 0.60 |
Nitrogen (N) | 0.05 to 0.20 |
Copper (Cu) | 0.05 to 0.60 |
Limits are per ASTM A790. ASTM A240 strip is held to 0.030% sulfur maximum.
S32304 Mechanical Properties
Property | Value |
|---|---|
Tensile Strength, min | 600 MPa (87 ksi) |
Yield Strength (0.2% offset), min | 400 MPa (58 ksi) |
Elongation in 50 mm, min | 25% |
Hardness, max | 290 HBW / 30 HRC |
Lean Duplex UNS S32304 Welded Pipes & Tubes Equivalent Grades
Standard | Designation |
|---|---|
UNS | S32304 |
EN / Werkstoff | 1.4362 (X2CrNi23-4) |
Common name | Duplex 2304, SAF 2304 |
ASTM pipe / tube | A790 / A789 / A928 |
316L vs S32304 vs S32205
Property | 316L | S32304 | S32205 |
|---|---|---|---|
Chromium | 16 to 18% | 21.5 to 24.5% | 22.0 to 23.0% |
Nickel | 10 to 14% | 3.0 to 5.5% | 4.5 to 6.5% |
Molybdenum | 2.0 to 3.0% | 0.05 to 0.60% | 3.0 to 3.5% |
Nitrogen | Not specified | 0.05 to 0.20% | 0.14 to 0.20% |
Min. yield strength | 170 MPa | 400 MPa | 450 MPa |
PREN (spec range) | 22.6 to 27.9 | 22.5 to 29.7 | 34.1 to 37.8 |
PREN is worked out as Cr + 3.3 Mo + 16 N, using the minimum and maximum of each specified range. Yield values are ASTM A790 and ASTM A312 minimums.
Where chlorides are higher or pitting is the main risk, step up to UNS S32205 duplex pipes and tubes. For a lower nickel lean duplex, see our UNS S32101 welded pipes and tubes.
Applications of S32304 Welded Pipes and Tubes
- Water and wastewater treatment piping
- Pulp and paper process lines
- Heat exchanger and cooler tubes; see our heat exchanger tubes
- Chemical tank and transfer lines in place of 316L
- Structural and architectural hollow sections
Testing and Documentation
Every order of S32304 welded pipe and tube goes through the checks below at our testing facility or approved third party labs.
- Chemical analysis and PMI
- Tension and hardness tests
- Flattening test, with flange test on tube
- Hydrostatic or eddy current test on every length
- Weld seam radiography for ASTM A928 classes that call for it
- Ferrite content check on weld and base metal on request
- Visual and dimensional inspection, including weld bead height
Mill test certificates are issued to EN 10204 3.1, with 3.2 available on request. You can view our approvals on the certificates page.
Packing and Marking
Each length is marked with the standard, UNS S32304, size, heat number and manufacturer name. Ends are capped, and pipes are kept apart from carbon steel and packed in bundles or wooden boxes. Read more about our packing and despatch process.
Request a Quote for UNS S32304 Welded Pipes & Tubes
Send us the OD or NB, wall or schedule, standard (A789, A790 or A928), length and quantity, and our team will reply with price and delivery. Use the enquiry form or reach us through the contact page.
Frequently Asked Questions
What is UNS S32304?
UNS S32304 (Duplex 2304, EN 1.4362) is a lean duplex stainless steel with 21.5% to 24.5% chromium, 3.0% to 5.5% nickel and up to 0.60% molybdenum.
Which standards cover S32304 welded pipe?
ASTM A790 covers welded pipe, ASTM A789 covers welded tube, and ASTM A928 covers electric fusion welded pipe with filler. EN 10217-7 covers 1.4362 welded tube.
Is S32304 a replacement for 316L?
Often, yes. S32304 has pitting resistance close to 316L, much better resistance to chloride stress corrosion cracking and more than twice the minimum yield strength.
What is the minimum yield strength of S32304 pipe?
ASTM A790 sets 400 MPa (58 ksi) minimum yield and 600 MPa (87 ksi) minimum tensile strength for S32304.
What is the maximum service temperature for S32304?
Like other duplex grades, S32304 is generally kept below about 300°C to avoid 475°C embrittlement.
