ASTM A333 Seamless Carbon Steel Pipe
Dec 04, 2025
ASTM A333 Seamless Carbon Steel Pipe description
ASTM A333/ASME SA333 steel pipe is designed for low-temperature environments and is available in both seamless and welded forms. It is widely used in low-temperature pressure vessels and cryogenic heat exchanger piping systems.
Standard stock specifications for ASTM A333/ASME SA333 pipes typically range from 8 to 1240 mm (OD) × 1 to 200 mm (wall thickness) (i.e., 1/8" to 48" with schedules SCH5S to SCH160, STD, XS, XXS). These dimensions can be customized to meet specific application requirements.
ASTM A333 Seamless Carbon Steel Pipe Specification
OD: NPS 1/8″ TO 30″
WT: 2.0mm-60mm Schedule: SCH40, SCH60, XS, SCH80, SCH100, SCH120, SCH140, SCH160, XXS
Grade: ASTM A333 Gr. 1, Gr. 3, Gr. 6...
Single Random: 17′ ~ 24′ lengths
Double Random: 36′ ~ 44′ lengths
A333 Pipe Chemical Composition & Mechanical Properties
| Chemical | Grade | C | Si | Mn | P | S |
| composition | Grade 1 | ≤0.30 | 0.40~1.06 | ≤0.025 | ≤0.025 | |
| Grade 3 | ≤0.19 | 0.18~0.37 | 0.31~0.64 | ≤0.025 | ≤0.025 | |
| Grade 4 | ≤0.12 | 0.18~0.37 | 0.50~1.05 | ≤0.025 | ≤0.025 | |
| Grade 6 | ≤0.30 | ≥0.10 | 0.29~1.06 | ≤0.025 | ≤0.025 | |
| Grade 7 | ≤0.19 | 0.13~0.32 | ≤0.90 | ≤0.025 | ≤0.025 | |
| Grade 8 | ≤0.13 | 0.13~0.32 | ≤0.90 | ≤0.025 | ≤0.025 | |
| Grade 9 | ≤0.20 | 0.40~1.06 | ≤0.025 | ≤0.025 | ||
| Grade 10 | ≤0.20 | 0.10~0.35 | 1.15~1.50 | ≤0.03 | ≤0.015 | |
| Grade 11 | ≤0.10 | ≤0.35 | ≤0.6 | ≤0.025 | ≤0.025 | |
| Mechanical | Grade | Tensile Strength (MPa) | Yield Point (MPa) | Elongation (%) | ||
| Property | Y | X | ||||
| Grade 1 | ≥380 | ≥205 | ≥35 | ≥25 | ||
| Grade 3 | ≥450 | ≥240 | ≥30 | ≥20 | ||
| Grade 4 | ≥415 | ≥240 | ≥30 | ≥16.5 | ||
| Grade 6 | ≥415 | ≥240 | ≥30 | ≥16.5 | ||
| Grade 7 | ≥450 | ≥240 | ≥30 | ≥22 | ||
| Grade 8 | ≥690 | ≥515 | ≥22 | |||
| Grade 9 | ≥435 | ≥315 | ≥28 | |||
| Grade 10 | ≥550 | ≥450 | ≥22 | |||
| Grade 11 | ≥450 | ≥240 | ≥18 | |||
ASTM A333 vs ASTM A671 Comparison Table
| Parameter | ASTM A333 | ASTM A671 |
|---|---|---|
| Standard Type | Low-Temp Seamless/Welded Pipe | Cryogenic/Cryo EFW Pipe (Electric-Fusion-Welded) |
| Manufacturing | ✅ Seamless: Hot-rolled/Cold-drawn ✅ Welded: SAW |
EFW Only: Plate rolling + SAW |
| Material Scope | Carbon Steel/Nickel Alloys (C-Mn, Ni) | Carbon Steel/Low-Alloy Steel (C-Mn, Cr-Mo) |
| Cryo Certification | Full-Pipe Charpy Test (-196°C to +50°C) | Weld-Only Impact Test (Class CC+ only) |
| Design Temp Range | -196°C ~ +50°C (Gr.8: -196°C) | -45°C ~ +260°C (CC70: -45°C) |
| Wall Thickness Cap. | ≤200 mm (seamless limitations) | Heavy Walls (up to 300+ mm) |
| Diameter Range | 8–1240 mm | Large DIA (up to 4000+ mm) |
| Inspection Focus | Full-body cryo toughness | Weld defect control (100% RT/UT) |
| Typical Grades | Gr.1(-29°C), Gr.6(-45°C), Gr.8(-196°C) | CA/CB/CC/CD/CE (CC65: -30°C, CC70: -45°C) |
| Applications | LNG pipes (-162°C), LN₂ systems (-196°C) | Cryo tanks, large-dia process pipes (>-45°C) |
| Cost Advantage | High cost for Ni grades (e.g., Gr.8) | 30–50% cost savings for large sizes |
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