ASTM A671 / A671M pipe is a widely recognized Standard Specification developed by the American Society for Testing and Materials (ASTM) for Electric-Fusion-Welded (EFW) steel pipes. These pipes are specifically designed for atmospheric and lower temperature services where high-pressure performance is critical.
This specification plays a vital role in piping systems across various industries such as petrochemical, oil & gas, power generation, and process industries, where strength, reliability, and weld integrity are of utmost importance.
Pipes under this specification are fabricated using pressure-vessel grade carbon steel plates. The plates are first rolled into cylindrical shapes and then joined using the electric-fusion welding process (EFW). This method ensures a strong, consistent longitudinal weld, which is vital for pressure-bearing applications.
The raw plates must conform to specific material grades such as:
These plates are chosen for their superior mechanical properties, ductility, and resistance to brittle fracture, especially in low-temperature environments.
Pipes are offered in multiple grades, representing different steel chemistries & strength levels. Here’s a snapshot of three common grades:
Grade | C (% max) | Mn (%) | P, S (%) max | Si (%) |
CC60 | 0.21 | 0.79–1.30 | 0.035 | – |
CC65 | 0.24 | 0.79–1.30 | 0.035 | – |
CC70 | 0.27 | up to ~1.30 | 0.035 | – |
For reference, CA55 is ~0.28% C, CB60 ~0.24% C, CC70 ~0.31% C longma-group.comvalouralloys.com+3astrometsteel.com+3metcoresteel.com+3.
Typical mechanical characteristics by grade:
Grade | Yield (MPa) | Tensile (MPa) | Elongation (%) |
CC60 | ≥ 220 | 415–550 | ≥ 25 |
CC65 | ≥ 240 | 450–585 | ≥ 23 |
CC70 | ≥ 260 | 485–620 | ≥ 21 |
Matches the requirements for pressure-sensitive applications .
Pipes are subdivided into classes based on heat treatment, radiography (RT), and hydrostatic pressure testing (PHWT). Here’s a breakdown:
Class | Heat‑Treatment | Radiography (RT) | Pressure Test (PHWT) |
10–13 | None | Optional or none | Optional or none |
20–23 | Stress‑relieved | RT in Class 22/23 | PHWT in Class 20/22 |
30–33 | Normalized | RT in 32/33 | PHWT optional |
40–43 | Normalized & tempered | RT in 42/43 | PHWT optional |
50–53 | Quenched & tempered | RT in 52/53 | PHWT optional |
A robust suite of tests ensures safety and performance:
Example from Grade CC65 @400 °F (per ANSI B36.10):
NPS OD (in) SCH 40 ψ SCH 80 ψ 1″ 1.315 ~4,956 ~6,670 6″ 6.625 ~2,071 ~3,195 12″ 12.75 ~961 ~1,268 24″ 24 ~510 ~766 Wall thickness examples:
ASTM A671 Carbon Steel EFW Pipes offer a versatile combination of strong chemical/mechanical performance, tailored treatment and inspection classes, precise sizing, and reliable quality systems—ideal for demanding service environments.
If you’d like, I can also provide:
Whether you’re based in India or shipping internationally, we’re here to make sourcing simple. We supply across the USA, Canada, Australia, Germany, Brazil , and the United Kingdom. Fast quotes, custom sizes, and bulk orders available.
Let us know what you need—we’ll take care of the rest
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