UNS S32900 Welded Pipes & Tubes

The UNS S32900 welded pipes & tubes are often used in applications that aim to replicate the Type 329 duplex piping system. Referred to in various ways as Grade 329, this duplex stainless steel has 23%-28% Cr, 2.5%-5% Ni & 1%-2% Mo content and a minimum yield strength of 485 MPa. Its welded form is particularly useful for replacement sections, extensions and maintenance work where the existing material grade needs to be maintained. Amardeep Steel supplies Type 329 welded pipes and tubes to ASTM A789 and A790. For heat exchanger tubing, see our UNS S32900 seamless pipes and tubes. For new welded systems, compare 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 S32900 Welded Pipes and Tubes?

Type 329 is one of the earliest duplex stainless steels. Its high chromium and mixed austenite and ferrite structure give about twice the strength of 316L and much better resistance to chloride stress corrosion cracking. Service is generally kept below about 300°C.

Why Solution Annealing Matters for Welded 329

S32900 has no nitrogen requirement in ASTM A790 and allows up to 0.08% carbon. Without nitrogen, an as welded seam can end up with too much ferrite, which lowers toughness and corrosion resistance. Solution annealing and rapid cooling after welding, as ASTM A789 and A790 require, restores the balance. For new welded systems, nitrogen alloyed 2205 is usually the better choice.

Applications of S32900 Welded Pipes and Tubes

• Replacement piping for existing Type 329 plant
• Cooling water and brine lines
• Petroleum refining and petrochemical process lines
• Pulp and paper process piping

Testing and Documentation

Every order of S32900 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
• 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 S32900, 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.