ASTM A312 TP309S Welding Thin Wall Steel Tubing
Type：Welded
Technique：Cold Finished/Argon Arc Welding
Surface Treatment：Annealing and Pickling/Polished
Section Shape：Round
Length：Customized by Client and Typically 6000mm
Specification：OD 6.35~762mm
Manufacturer of ASTM A312 TP309S Welded SS tube
GNEE is a leading supplier of stainless steel products with extensive experience in supplying ASTM A312 TP309S stainless steel pipes widely used across diverse industries.
Our manufactured 309S stainless steel pipes are produced with chromium and nickel, elements that form a protective oxide layer on the pipe surface to effectively resist oxidation and corrosion even in harsh environments. In terms of mechanical properties, the material features a minimum tensile strength of 590 MPa. Its high tensile strength and yield strength enable the pipes to withstand heavy loads and high pressure. Furthermore, it supports intermittent operation at temperatures up to 980 °C and continuous operation at up to 1100 °C, making it ideal for high‑temperature working conditions.
Our thin‑walled 309S welded pipes are seam‑formed via high‑frequency current without filler metal through autogenous welding. After welding, the pipes undergo integral solution annealing at 1050–1120 °C to relieve welding stress. Subsequent internal and external weld dressing and pickling treatments deliver smooth weld surfaces, ensuring outstanding performance in a variety of industrial environments.
To meet diversified application demands, we provide ASTM A312 TP309S stainless steel pipes in a full range of sizes and diameters, alongside customized surface treatment services tailored to client requirements.
If you are sourcing this material for a project, please let me know:
Do you require a seamless (SML) or welded (WLD) pipe type?
What Nominal Pipe Size (NPS) and Schedule (wall thickness) do your design pressures demand?
Specification Chart of ASTM A312 TP309S Pipe
Chemical Analysis of SS TP309s Pipe
| Grade | Iron | Chromium | Nickel | Manganese | Silicon | Carbon | Phosphorous | Sulfur |
| 309 Stainless Steel | 60 | 23 | 14 | 2 | 1 | 0.20 | 0.045 | 0.030 |
Dimensional Tolerances of TP309S SS tube
| 1/8～1½ | ±0.4 mm |
| ＞1½～4 | ±0.8 mm |
| ＞4～8 | ±1.6 mm |
| ＞8～18 |
±2.4 mm |
| ＞18～26 | ±3.2 mm |
wall thickness tolerance of TP309S SS Pipe
| 1/8～2½ | +20% | −12.5% |
| 3～18,t/D≤5% | +22.5% | −12.5% |
| 3～18,t/D＞5% | +15% | −12.5% |
| ≥20 | +17.5% | −12.5% |
How to choose between TP309S and TP310S
| Item | TP309S | TP310S |
|---|---|---|
| Cr&Ni Content | Cr 22%–24%, Ni 12%–15% | Cr 24%–26%, Ni 19%–22% |
| Continuous Working Temp | Around 1100℃ | Up to 1150℃ |
| Sulfidation Resistance | Excellent | Ordinary |
| Oxidation Resistance | Good | Superior |
| Cost | Moderate, cost‑effective | Higher due to rich nickel |
| Typical Uses | Boiler flue pipes, incinerator exhaust pipes | Heat‑treatment furnace tubes, clean high‑temperature kiln piping |
For sulfur‑containing media, flue gas working conditions and cost control requirements, choose TP309S;
For clean high‑temperature environments, pursuit of ultimate oxidation resistance and sufficient budgets, choose TP310S.
Applications of ASTM A312 TP309S SS Pipes
ASTM A358 TP309S stainless steel is mainly applied in the construction industry and also widely used in the chemical industry.
If you need more details, let me know:
What size, schedule, or outer diameter do you need?
What is your operating temperature or environment?
Quality Control of ASTM A312 TP309S Pipe
Our stainless steel pipes undergo multi‑level quality inspection throughout the whole production process. Raw materials are subject to spectral composition testing first, and finished products of each batch go through hydrostatic pressure tests and eddy current inspection to detect inner‑wall cracks and pores. After production, sampling checks are conducted on outer diameter, dimensional tolerances of the inner wall and surface finish. EN10204 3.1/3.2 material certificates and inspection reports can be issued for each batch to realize traceable quality.
chemical composition testing
outer diameter measurement
wall thickness measurement
If you are interested in our product inspection and testing processes, please click the links below to view relevant inspection videos and reports.
premium packaging
Our stainless steel pipes adopt multi‑layer protective packaging. Plastic end caps are fitted at both pipe ends to block moisture, and each pipe is wrapped with VCI anti‑rust paper to isolate salt fog and dampness. Small‑diameter pipes are bundled with steel straps with rubber pads to avoid indentations, while large‑diameter ones are protected individually and separated by wooden spacers.
waterproof film
wooden case packaging
moisture-proof packaging
Customer Cases
Project Background
For a new waste‑heat boiler project of an engineering client in the UAE, the flue‑gas pipeline operates continuously at 550‑850 °C with sulfide‑containing flue gas. Pipes are required to deliver both high‑temperature oxidation resistance and sulfidation‑corrosion resistance. ASTM A312 TP309S pickled welded pipes were selected.
GNEE Supply Solution
Product: ASTM A312 TP309S TIG welded pipes with pickled surface finish.
Process: Integral solution annealing at 1050‑1120 °C after welding. Both internal and external weld seams are milled to remove weld reinforcement and relieve residual stress.
Quality Control: 100% hydrostatic test, eddy‑current and ultrasonic testing (UT), and PMI material verification. Full documentation including EN10204 3.1 material test certificate, heat‑treatment records and NDT inspection reports are provided.
Export Packing: VCI anti‑rust paper, plastic end caps, fumigated wooden crates for seaworthy marine shipment. Custom client shipping marks can be printed.
Project Outcome
Since commissioning, the equipment has been in continuous service for 18 months. No intergranular corrosion or high‑temperature creep deformation has been found on weld seams, showing stable sulfidation‑corrosion resistance. The client has signed an annual long‑term framework supply agreement.
Group photos with clients
client discussions
client site visits
FAQ
1.What are the benefits of pickling ASTM A312 TP309S stainless steel pipes?
Pickling treatment for ASTM A312 TP309S stainless steel pipes aims to thoroughly remove surface scale, chromium‑depleted layers and ferric ion contamination generated during high‑temperature processes such as hot rolling, solution heat treatment and welding, so as to restore and significantly improve the pipes' high‑temperature corrosion resistance and oxidation resistance.
2.What are the differences in high‑temperature resistance among 309S and 310S?
309S: It can work continuously at roughly 1100℃ with prominent sulfidation corrosion resistance, making it suitable for boiler flue gas operating conditions;
310S: It supports continuous operation up to 1150℃ and delivers the best oxidation resistance in clean high‑temperature environments, yet it has poorer sulfidation resistance than 309S and a higher cost.
3.What is the lead time for ASTM A312 TP309S stainless steel pipes?
Within 10-25 days or asap if we have enough stock
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