ASTM A671 CF70 EFW pipe is associated with 70 ksi nickel steel pipe for low-temperature service. Amardeep Steel supplies the current grades used for this strength level: CFB70, manufactured from ASTM A203 Grade B plate with 2.25% nickel, and CFE70, made from ASTM A203 Grade E plate with 3.5% nickel. Buyers looking for the lower nickel option can refer to our ASTM A671 CFB70 pipes, while the higher nickel grade is covered by our ASTM A671 CFE70 pipes. You can also explore the complete ASTM A671 EFW pipe range. Every order includes plate and weld certificates, specified temperature impact test results and radiography reports.
What Is ASTM A671 CF70 EFW Pipe?
ASTM A671 covers electric fusion welded steel pipe for atmospheric and lower temperatures. Its nickel steel grades are made from ASTM A203 plate. Nickel lowers the temperature at which steel turns brittle, so these grades are used where carbon steel pipe would not have enough toughness.
CF70 Today: CFB70 or CFE70
Older A671 lists used CF65 and CF70 for the nickel steel grades. The current table splits them by A203 plate grade: CFA65, CFB70, CFD65 and CFE70. A CF70 order therefore means one of two current grades with the same 70 ksi strength, and the nickel content decides which. Choose CFB70 for moderate low temperature service and CFE70 for colder service. Tell us your design temperature and we will confirm the grade.
ASTM A671 CF70 EFW Pipe Specifications
Parameter | Details |
|---|---|
Specification | ASTM A671 / ASME SA671 |
Grade | CF70, supplied as CFB70 or CFE70 |
Plate Material | ASTM A203 Grade B (2.25% Ni) or Grade E (3.5% Ni) |
Manufacturing Process | Electric fusion welded (EFW) with filler metal, longitudinal seam |
Size Range | 16 inch (406 mm) OD and larger as standard, smaller sizes on request |
Wall Thickness | Up to 75 mm (3 inch) |
Common Classes | Class 22 and Class 32, with impact testing to the project specification |
Length | Single random, double random and cut lengths |
Ends | Bevelled end or plain end |
Test Certificate | EN 10204 3.1, with 3.2 available on request |
ASTM A671 CF70 EFW Pipe Chemical Composition
Element (%), plate up to 50 mm | A203 Gr B (CFB70) | A203 Gr E (CFE70) |
|---|---|---|
Carbon (C) | 0.21 max | 0.20 max |
Manganese (Mn) | 0.70 max | 0.70 max |
Phosphorus (P) | 0.025 max | 0.025 max |
Sulfur (S) | 0.025 max | 0.025 max |
Silicon (Si) | 0.15 to 0.40 | 0.15 to 0.40 |
Nickel (Ni) | 2.10 to 2.50 | 3.25 to 3.75 |
ASTM A671 CF70 EFW Pipe Mechanical Properties
Property | Requirement |
|---|---|
Tensile Strength | 485 to 620 MPa (70 to 90 ksi) |
Yield Strength, min | 275 MPa (40 ksi) |
Elongation in 50 mm, min | 21% |
Impact Testing and Service Temperature
2.25% nickel steel (CFB70) is commonly selected for service down to about minus 60 degrees Celsius and 3.5% nickel steel (CFE70) down to about minus 100 degrees Celsius. The impact test temperature is set by the purchaser and the governing code.
A671 Pipe Classes Explained
Class (first digit) | Heat Treatment on Pipe | Class (second digit) | Weld Radiography and Pressure Test |
|---|---|---|---|
1x | None | x0 | Neither |
2x | Stress relieved | x1 | Radiography only |
3x | Normalized | x2 | Radiography and pressure test |
4x | Normalized and tempered | x3 | Pressure test only |
5x | Quenched and tempered |
Classes ending in 2 include full radiography and a hydrostatic test. Nickel steel pipe is normally ordered stress relieved (Class 22) or normalized (Class 32).
ASTM A671 Nickel Steel Grades Compared
Property | CFA65 | CFB70 | CFD65 | CFE70 |
|---|---|---|---|---|
A203 Plate Grade | A | B | D | E |
Nickel | 2.10 to 2.50% | 2.10 to 2.50% | 3.25 to 3.75% | 3.25 to 3.75% |
Tensile Strength | 450 to 585 MPa | 485 to 620 MPa | 450 to 585 MPa | 485 to 620 MPa |
Yield Strength, min | 255 MPa | 275 MPa | 255 MPa | 275 MPa |
For cryogenic service, 9% nickel grades are used; see our ASTM A333 Grade 8 pipes.
Heat Treatment of ASTM A671 CF70 EFW Pipe
- Post weld heat treatment: 590 to 635 degrees Celsius (1100 to 1175 degrees Fahrenheit)
- Normalizing: 950 degrees Celsius (1750 degrees Fahrenheit) maximum
Applications of ASTM A671 CF70 EFW Pipe
- Propane, propylene and LPG transfer lines (CFB70)
- Ammonia refrigeration and storage piping (CFB70)
- Ethane and cold gas processing lines (CFE70)
- Cold flare and blowdown headers (CFE70)
Testing and Documentation
Every order of A671 CF70 pipe goes through the checks below at our testing facility or approved third party labs.
- Chemical analysis of plate and deposited weld metal
- Transverse tension test
- Transverse guided weld bend test
- Charpy impact test of plate, weld and heat affected zone at the specified temperature
- Radiography of the weld seam (Class x1 and x2)
- Hydrostatic test (Class x2 and x3)
- Visual and dimensional inspection
Mill test certificates are issued to EN 10204 3.1, with 3.2 available on request. You can view our approvals on the certificates page.
Packing and Marking
Each length is marked with the specification, grade, class, size, heat number and manufacturer name. Bevelled ends are protected with caps or bevel protectors, and lengths are shipped loose with dunnage or in lashed bundles. Read more about our packing and despatch process.
Request a Quote for ASTM A671 CF70 EFW Pipe
Send us the OD, wall thickness, nickel grade, class, impact test temperature, length and quantity, and our team will reply with price and delivery. Use the enquiry form or reach us through the contact page.
Frequently Asked Questions
What is ASTM A671 CF70 pipe?
ASTM A671 CF70 is the older name for 70 ksi nickel steel EFW pipe for low temperature service. It is now supplied as CFB70 (A203 Grade B, 2.25% nickel) or CFE70 (A203 Grade E, 3.5% nickel).
How do I choose between CFB70 and CFE70 for a CF70 order?
Both have the same strength. Choose CFB70 for service down to about minus 60 degrees Celsius and CFE70 for colder service down to about minus 100 degrees Celsius, as confirmed by your project specification.
What is the tensile strength of A671 CF70 pipe?
Both CFB70 and CFE70 have a tensile strength of 485 to 620 MPa (70 to 90 ksi) and a minimum yield strength of 275 MPa (40 ksi).
What plate is used for A671 CF70 pipe?
ASTM A203 Grade B plate for CFB70 and ASTM A203 Grade E plate for CFE70.
