ASTM A358 EFW 347 Pipes

ASTM A358 EFW 347 Pipes

ASTM A358 EFW 347 Pipes are niobium (columbium) stabilized austenitic stainless steel pipes manufactured using the Electric Fusion Welding (EFW) process. The addition of niobium enhances resistance to intergranular corrosion and improves performance in elevated temperature applications.

Grade 347 is widely used in environments where resistance to carbide precipitation during welding and high-temperature exposure is critical. These pipes offer excellent oxidation resistance and long-term structural stability.

Specifications

Standard	ASTM A358 / ASME SA358
Grade	347
UNS Number	S34700
Manufacturing Process	Electric Fusion Welded (EFW)
Size Range	1/2" NB to 24" NB
Wall Thickness	Schedule 5S to Schedule 80S
Length	6 Meters Standard / Custom Length
Surface Finish	Annealed & Pickled, Polished, Matte Finish
End Type	Plain End, Beveled End, Threaded

Key Benefits

• Excellent Intergranular Corrosion Resistance: Niobium stabilization prevents carbide precipitation.
• High-Temperature Stability: Suitable for prolonged elevated temperature service.
• Strong Welded Structure: EFW process ensures uniform seam integrity.
• Good Oxidation Resistance: Performs well in high heat and oxidizing environments.
• Durable & Reliable: Ideal for critical industrial systems.

Chemical Composition (Typical)

Element	347 (%)
Carbon	0.08 Max
Chromium	17.0 – 19.0
Nickel	9.0 – 13.0
Niobium (Columbium)	10xC Min – 1.00 Max

Applications

• Heat Exchangers
• Boilers & Superheaters
• Petroleum Refineries
• Power Generation Plants
• Chemical Processing Equipment

Quality Testing

• Hydrostatic Testing
• Ultrasonic Testing (UT)
• Radiographic Testing (RT)
• PMI Testing
• Dimensional Inspection

Conclusion

ASTM A358 EFW 347 Pipes offer superior high-temperature strength, excellent resistance to intergranular corrosion, and dependable welded construction. Their niobium-stabilized composition ensures long-term reliability in demanding industrial environments.