In the world of industrial piping, Electric Fusion Welded (EFW) pipes are a common solution for medium to high-pressure applications, where corrosion resistance, mechanical strength, and reliable weld integrity are essential. Two common types of EFW pipes specified in industrial projects are ASTM A358 GR 316 CL.3 and ASTM A671 GR CC60 CL.22.
Though both are EFW pipes, they differ significantly in material composition, temperature resistance, application, and dimensional standards. This article explains what EFW pipes are and compares these two specifications to help engineers and buyers select the right product for their projects.
EFW Steel Pipes Produced By Haihao Group
What is an EFW Pipe?
EFW (Electric Fusion Welded) pipe refers to a pipe made by welding stainless steel or carbon steel plate using high-frequency electric current, without the use of filler metal. The process is ideal for producing large-diameter, high-integrity welded pipe, often used in oil & gas, chemical, and power generation industries.
EFW differs from SAW (Submerged Arc Welded) in that it uses electric resistance or arc heating without flux, and is usually applied to stainless steel and alloy steel.
Dimension Standards: ASME B36.19M vs B36.10M
| Standard | Pipe Type | Common Materials | Wall Thickness |
| ASME B36.19M | Stainless steel pipe | ASTM A358, A312, A269, etc. | Schedules 5S, 10S, 40S, 80S (thin wall) |
| ASME B36.10M | Carbon/alloy steel pipe | ASTM A53, A106, A671, A333, etc. | Schedules STD, XS, XXS (heavier wall) |
ASTM A358 316 CL.3 EFW pipe follows ASME B36.19M dimensional standards.
ASTM A671 CC60 CL.22 EFW pipe follows ASME B36.10M standards.
Material Comparison: A358 GR 316 CL.3 vs A671 GR CC60 CL.22
| Property | ASTM A358 GR 316 CL.3 | ASTM A671 GR CC60 CL.22 |
| Material Type | Austenitic stainless steel | Carbon steel (with impact requirements) |
| Welding Process | Electric Fusion Welded (EFW) | Electric Fusion Welded (EFW) |
| Base Material Spec | ASTM A240 Type 316 stainless steel | ASTM A285 Grade C carbon steel |
| Class Definition | CL.3 = Solution annealed + Radiographic Test | CL.22 = Post-weld heat-treated + Impact tested |
| Corrosion Resistance | Excellent (resistant to chlorides and acids) | Poor (requires internal/external coating for service) |
| Tensile Strength (min) | ≥ 515 MPa | ≥ 379 MPa |
| Yield Strength (min) | ≥ 205 MPa | ≥ 205 MPa |
| Temperature Service Range | Up to ~870°C | Low to medium-temperature applications |
| Impact Test | Not mandatory unless specified | Mandatory at specified temperature (e.g. -46°C) |
| Typical Applications | Chemical processing, pharmaceuticals, seawater | Oil & gas, water pipelines, power plants |
| Standard Dimensions | ASME B36.19M (5S/10S/40S/80S) | ASME B36.10M (STD, XS, XXS, etc.) |
Key Technical Differences
1.Material & Corrosion Resistance
A358 GR 316 is made from austenitic stainless steel, containing 16-18% chromium, 10-14% nickel, and 2-3% molybdenum, which makes it highly resistant to pitting, crevice corrosion, and most acids.
A671 GR CC60 is made from carbon steel, which is not corrosion-resistant and generally requires epoxy or galvanized coating in corrosive environments.
2.Weld Integrity & Heat Treatment
CL.3 (A358) requires radiographic inspection of the weld seam and solution annealing to restore corrosion resistance and mechanical properties.
CL.22 (A671) must undergo post-weld heat treatment (PWHT) and must pass impact testing to confirm ductility at low temperatures (e.g., –46°C).
3.Service Conditions
A358 GR 316 CL.3 is ideal for high-corrosion, high-temperature applications (up to ~870°C), often used in chemical plants, desalination units, and refineries.
A671 GR CC60 CL.22 is suitable for moderate-temperature, low-pressure services like oil pipelines, cooling water, and process steam lines, especially where impact toughness is required.
Selection Guidelines
| Application Condition | Recommended Pipe Type |
| Highly corrosive media (chlorides, acids) | ASTM A358 GR 316 CL.3 |
| Non-corrosive fluid, low temp impact | ASTM A671 GR CC60 CL.22 |
| Requires stainless steel, high temp | ASTM A358 GR 316 CL.3 |
| Requires carbon steel with impact test | ASTM A671 GR CC60 CL.22 |
| B36.19M project (SS piping system) | ASTM A358 GR 316 CL.3 |
| B36.10M project (CS piping system) | ASTM A671 GR CC60 CL.22 |
While both ASTM A358 GR 316 CL.3 and ASTM A671 GR CC60 CL.22 are Electric Fusion Welded (EFW) pipes, they serve fundamentally different purposes. The former is a high-performance stainless steel product designed for corrosive and high-temperature environments, while the latter is a carbon steel pipe tailored for low- to medium-temperature systems with impact resistance requirements.
Procurement professionals must carefully consider not just the welding process, but the material composition, heat treatment class, and standard dimensions when sourcing pipe products.
Need help selecting the right EFW pipe for your project? Haihao Group offers complete solutions in both stainless and carbon steel piping systems, with full traceability, testing, and documentation.
Contact us today to receive a quotation or technical consultation for your piping needs. Email:sales@haihaogroup.com
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