Our ASTM B677 seamless pipes are manufactured from high-alloy austenitic stainless steels – UNS N08925, N08354, and N08926. These grades are specifically designed for applications requiring superior corrosion resistance beyond what standard 300 series stainless steels (such as 316L) can offer.
These materials are often referred to as “super austenitic” or “6% molybdenum” grades, providing exceptional resistance to:
Pitting and crevice corrosion (in chloride-containing environments)
Stress corrosion cracking (SCC)
Sulfuric, phosphoric, and organic acids
Key advantages:
- PREN (Pitting Resistance Equivalent Number) > 40 for N08926
- Excellent performance in seawater, brackish water, and sour gas environments
- High strength with good ductility and weldability
- Suitable for downhole tubulars, heat exchangers, and chemical processing
Product Specification Sheet – ASTM B677 Seamless Pipes
| Category | Details |
|---|---|
| Standard | ASTM B677 / ASME SB-677 (Seamless austenitic stainless steel pipe for corrosive service) |
| Grades | UNS N08925 , UNS N08354 , UNS N08926 |
| Outside Diameter | 6.0mm – 610mm (1/4″ – 24″) – larger sizes available upon request |
| Wall Thickness | 0.5mm – 40mm (covers Sch 5S through Sch XXS) |
| Length | Single random: 5–7m / Double random: 10–13m / Fixed lengths available upon request |
| Manufacturing Process | Seamless (SMLS) – hot finished or cold finished |
| Delivery Condition | Solution annealed & pickled (other conditions available upon request) |
| Packaging | Standard export bundling with plastic caps, steel straps, and wooden crates (or as required) |
| Certification | EN 10204 Type 3.1 (Mill Test Certificate) / Type 3.2 (third-party inspection available: SGS, BV, TUV) |
| Main Applications | Seawater cooling systems, flue gas desulfurization (FGD), chemical processing, marine engineering, oil & gas (sour service), desalination plants, heat exchangers, condensers |
Chemical Composition
| Element | UNS N08925 (1.4524) | UNS N08354 (1.4547) | UNS N08926 (1.4529) |
|---|---|---|---|
| Carbon (C), max | 0.020 | 0.030 | 0.020 |
| Manganese (Mn), max | 1.00 | 1.00 | 2.00 |
| Silicon (Si), max | 0.50 | 0.50 | 0.50 |
| Phosphorus (P), max | 0.030 | 0.030 | 0.030 |
| Sulfur (S), max | 0.010 | 0.010 | 0.010 |
| Chromium (Cr) | 19.0 – 21.0 | 20.0 – 23.0 | 19.0 – 21.0 |
| Nickel (Ni) | 24.0 – 26.0 | 24.0 – 26.0 | 24.0 – 26.0 |
| Molybdenum (Mo) | 5.0 – 7.0 | 6.0 – 7.0 | 6.0 – 7.0 |
| Copper (Cu) | 0.8 – 1.5 | 0.5 – 1.0 | 0.5 – 1.5 |
| Nitrogen (N) | 0.10 – 0.20 | 0.15 – 0.25 | 0.15 – 0.25 |
| Iron (Fe) | Balance | Balance | Balance |
| PREN * | ≥ 35 | ≥ 44 | ≥ 43 |
*PREN (Pitting Resistance Equivalent Number) = %Cr + 3.3×%Mo + 16×%N
Mechanical Properties
| Property | UNS N08925 | UNS N08354 | UNS N08926 |
|---|---|---|---|
| Yield Strength Rp0.2 (MPa) | 260 | 310 | 295 |
| Yield Strength Rp0.2 (ksi) | 37.7 | 45.0 | 42.8 |
| Tensile Strength Rm (MPa) | 600 | 680 | 650 |
| Tensile Strength Rm (ksi) | 87.0 | 98.6 | 94.3 |
| Elongation (%), min | 35 | 35 | 35 |
| Hardness (HRB), max | 90 | 95 | 90 |
Supplementary Notes:
Mechanical properties are determined from the solution annealed condition.
For wall thicknesses exceeding 40mm, values may be subject to adjustment – please inquire.
Impact testing (Charpy V-Notch) can be performed upon request. Typical values: ≥60J at room temperature (longitudinal).
