The ASTM A671 CD70 EFW pipe is made from normalized ASTM A537 Class 1 plate and is intended for atmospheric and low-temperature service. Amardeep Steel supplies this grade for applications where the higher minimum yield strength of CD70 can be useful, particularly on larger lines where wall thickness is an important consideration. Its tensile range is the same as our ASTM A671 CC70 pipes, while CD70 offers a higher minimum yield strength. The grade forms part of our ASTM A671 EFW pipe range, along with other carbon steel pipes and tubes. Orders include plate and weld test certificates, radiography reports and full heat traceability.
What Is ASTM A671 CD70 EFW Pipe?
ASTM A671 covers electric fusion welded steel pipe, made by forming pressure vessel plate into a cylinder and welding the seam with filler metal, for atmospheric and lower temperatures. The pipe grade names the plate. CD70 is made from ASTM A537 Class 1, a manganese silicon steel supplied normalized.
Why Normalized A537 Plate Matters
Normalizing refines the grain of the plate, which raises yield strength and improves notch toughness compared with as rolled carbon steel plate. That is why CD70 reaches 345 MPa minimum yield while CC70, made from A516 Grade 70, reaches 260 MPa at the same tensile level.
ASTM A671 CD70 Pipe Specifications
Parameter | Details |
|---|---|
Specification | ASTM A671 / ASME SA671 |
Grade | CD70 |
Plate Material | ASTM A537 / A537M Class 1 (normalized) |
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 12, 22, 32 and 42 |
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 CD70 Chemical Composition
Element | Content (%), plate up to 40 mm |
|---|---|
Carbon (C) | 0.24 max |
Manganese (Mn) | 0.70 to 1.35 |
Phosphorus (P) | 0.025 max |
Sulfur (S) | 0.025 max |
Silicon (Si) | 0.15 to 0.50 |
Copper (Cu) | 0.35 max |
Nickel (Ni) | 0.25 max |
Chromium (Cr) | 0.25 max |
Molybdenum (Mo) | 0.08 max |
Plate over 40 mm thick allows a higher manganese range. The weld deposit is analysed separately for every lot.
ASTM A671 CD70 Mechanical Properties
Property | Requirement |
|---|---|
Tensile Strength | 485 to 620 MPa (70 to 90 ksi) |
Yield Strength, min (plate up to 65 mm) | 345 MPa (50 ksi) |
Yield Strength, min (plate over 65 mm) | 310 MPa (45 ksi) |
Elongation in 50 mm, min | 22% |
A671 Pipe Classes Explained
The class number tells you how the pipe is heat treated and tested. The first digit is heat treatment and the second digit is weld radiography and pressure testing.
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, which lets designers use a weld joint factor of 1.0 under ASME B31.3. Class 22 and Class 32 are the most common orders for CD70.
ASTM A671 CC70 vs CD70 vs CD80
Property | CC70 | CD70 | CD80 |
|---|---|---|---|
Plate | A516 Grade 70 | A537 Class 1 | A537 Class 2 |
Plate Condition | As rolled or normalized | Normalized | Quenched and tempered |
Tensile Strength | 485 to 620 MPa | 485 to 620 MPa | 550 to 690 MPa |
Yield Strength, min | 260 MPa | 345 MPa | 415 MPa |
Where yield strength does not drive the wall, A671 CC70 pipe is usually easier to source.
Heat Treatment of A671 CD70 Pipe
- Post weld heat treatment: 590 to 680 degrees Celsius (1100 to 1250 degrees Fahrenheit)
- Normalizing: 925 degrees Celsius (1700 degrees Fahrenheit) maximum
Applications of ASTM A671 CD70 Pipe
- Large diameter process lines at atmospheric and low temperature
- Headers and manifolds in gas processing plants
- Cold gas and LPG transfer lines, with impact testing to the project specification
- Cooling water and utility mains where wall weight matters
Testing and Documentation
Every order of A671 CD70 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 and weld where specified
- 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 CD70 EFW Pipe
Send us the OD, wall thickness, class, length, quantity and any impact test temperature, 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 CD70 pipe?
ASTM A671 CD70 is electric fusion welded steel pipe made from ASTM A537 Class 1 plate, a normalized manganese silicon steel, for atmospheric and low temperature service. It has a tensile strength of 485 to 620 MPa and a minimum yield of 345 MPa.
What is the difference between A671 CC70 and CD70?
CC70 is made from A516 Grade 70 plate with a minimum yield of 260 MPa. CD70 is made from normalized A537 Class 1 plate with a minimum yield of 345 MPa, so it allows thinner walls at the same tensile level.
What does Class 22 mean on A671 CD70 pipe?
Class 22 means the pipe is stress relieved after welding, the weld is fully radiographed and the pipe is hydrostatically tested.
What plate is used for A671 CD70?
A671 CD70 pipe is made from ASTM A537 / A537M Class 1 plate in the normalized condition.
