BS 3059-1 Hot Finished Carbon Steel Seamless Tube for Boiler (HFS 320)
Material
BS 3059-1 boiler tubes are hot finished seamless carbon steel tubes designed for boiler and superheater service where reliable pressure performance, good heat transfer, and consistent wall integrity are required. The BS 3059-1 scope covers plain-end tubes (seamless or welded) up to 127 mm OD and up to 12.5 mm wall thickness for boilers and superheaters.
A commonly supplied hot-finished seamless designation under this standard is HFS 320, a low-tensile carbon steel tube that can be supplied hot-finished and, when required, with normalizing/subcritical annealing practices to achieve the specified properties.
Specifications
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Standard: BS 3059-1:1987 (status shown as withdrawn/inactive by standard catalogs; still widely used for legacy projects and replacements)
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Grade / Designation: HFS 320 (Hot Finished Seamless)
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Product form: Seamless tube, hot finished (hot rolled/hot finished)
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Dimensional scope (per BS 3059-1): OD ≤ 127 mm; WT ≤ 12.5 mm
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Tube ends: Plain end (standard), bevelled/threaded available on request
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Length: SRL/DRL/fixed cut lengths available; up to ~16 m by request
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Delivery condition: Hot finished; normalizing/subcritical anneal can be applied when specified
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Inspection documents: Mill Test Certificate (EN 10204 3.1; 3.2 or third-party inspection available)
Main Features
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True seamless structure: eliminates weld-related weak points and improves pressure reliability.
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Stable mechanical performance for boiler circulation and superheater duties within the standard’s intended size range.
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Good fabrication behavior: suitable for bending, forming, and welding procedures typically used in boiler tube assemblies (with proper WPS/PQR).
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Quality-verifiable: chemistry + mechanical tests and common NDT options support safe acceptance for critical service.
Our Advantages
Buyers typically focus on grade compliance, dimensional accuracy, traceability, testing, and surface condition.
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Q: How do you ensure the tube truly matches BS 3059-1 HFS 320?
A: We provide heat-number traceability and MTCs showing chemical composition and tensile results, aligned with the ordered standard and grade. -
Q: What about OD/WT tolerance and fit-up issues during installation?
A: We run full dimensional checks (OD, WT, length, straightness) and keep the supply within the BS 3059-1 dimensional scope to reduce site rework and unexpected mismatch. -
Q: Can you support NDT and pressure-tightness verification?
A: NDT such as UT / ECT and hydrostatic testing can be provided as required, plus flattening/flaring checks commonly used for boiler tubes. -
Q: How do you prevent transit rust and surface-related rejection?
A: We offer oil-dip/varnish/phosphating/shot blasting/painting options and package to protect surfaces during shipment and storage. -
Q: Can we use third-party inspection (SGS/BV/TÜV) or special documentation?
A: Yes—third-party inspection reports and upgraded documentation packages (e.g., EN 10204 3.2 where applicable) can be arranged.
Chemical Composition
| Standard / Grade | C (%) | Si (%) | Mn (%) | P (%) | S (%) |
|---|---|---|---|---|---|
| BS 3059-1 HFS 320 | ≤0.16 | 0.10–0.35 | 0.30–0.70 | ≤0.04 | ≤0.04 |
| ASTM A210 Grade A-1 | ≤0.27 | ≤0.10 | ≤0.93 | ≤0.035 | ≤0.035 |
| EN 10216-2 P235GH (1.0345) | ≤0.16 | ≤0.35 | 0.60–1.20 | ≤0.025 | ≤0.015 |
| JIS G3461 STB340 | ≤0.18 | ≤0.35 | 0.30–0.60 | ≤0.035 | ≤0.035 |
| GB/T 5310 20G | 0.17–0.23 | 0.17–0.37 | 0.35–0.65 | ≤0.025 | ≤0.015 |
Mechanical Properties (5 related grades)
Mechanical properties can vary by size/thickness and delivery condition; values below reflect commonly published minimums/ranges for each grade family.
| Standard / Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) |
|---|---|---|---|
| BS 3059-1 HFS 320 | 320–480 | ≥195 | ≥25 |
| ASTM A210 Grade A-1 | ≥415 | ≥255 | ≥30 |
| EN 10216-2 P235GH (+N) | 360–480 | ≥235 (t≤16 mm) | 24–25 |
| JIS G3461 STB340 | ≥340 | ≥175 | ≥35* |
| GB/T 5310 20G | 410–550 | ≥245 | ≥24* |
*Elongation for STB340 and 20G is size-dependent in published tables; the values shown are commonly referenced minimums for typical boiler tube sizes.
Execution Standards (ASTM / EN / GOST / JIS / GB)
If your project accepts equivalent standards, the following are commonly used for boiler/pressure tube supply (final selection should match design code and operating temperature/pressure requirements):
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ASTM: ASTM A210/A210M, ASTM A192/A192M, ASTM A179/A179M
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EN: EN 10216 series (seamless tubes for pressure purposes, incl. elevated-temperature grades such as P235GH)
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GOST: GOST 8731 (technical requirements) + GOST 8732 (hot-deformed seamless pipes; assortment/dimensions)
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JIS: JIS G3461 (carbon steel boiler and heat exchanger tubes; e.g., STB340)
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GB: GB/T 3087 (low/medium pressure boiler) and GB/T 5310 (high pressure boiler)
Application Areas
Primary industries: steam boilers, power generation, petrochemical heating systems, industrial heat transfer equipment.
Where it is used inside the system
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Boilers: waterwall/circulation tubes, generating bank tubes, downcomers and connecting tube runs (within size limits)
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Superheaters / reheaters (where applicable by design): tube coils and interconnecting hot-side tubing
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Economizers / heat exchangers: heat-transfer tube bundles and recovery sections