ASTM A358 EFW 321H Pipes

ASTM A358 EFW 321H Pipes

ASTM A358 EFW 321H Pipes are high-carbon, titanium-stabilized austenitic stainless steel pipes manufactured using the Electric Fusion Welding (EFW) process. The higher carbon content in 321H enhances high-temperature strength and creep resistance compared to standard 321 grade.

These pipes are specifically designed for elevated temperature service in pressure vessels, heat exchangers, and refinery systems where improved mechanical strength and oxidation resistance are essential.

Specifications

Standard	ASTM A358 / ASME SA358
Grade	321H
UNS Number	S32109
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

• Enhanced High-Temperature Strength: Higher carbon improves creep and stress rupture resistance.
• Titanium Stabilization: Prevents carbide precipitation and intergranular corrosion.
• Excellent Oxidation Resistance: Performs well in continuous elevated temperature service.
• Strong Weld Integrity: EFW process ensures uniform seam strength and durability.
• Reliable Long-Term Performance: Suitable for demanding refinery and power plant applications.

Chemical Composition (Typical)

Element	321H (%)
Carbon	0.04 – 0.10
Chromium	17.0 – 19.0
Nickel	9.0 – 12.0
Titanium	5x(C+N) Min – 0.70 Max

Applications

• Petroleum Refineries
• Boilers & Superheaters
• Heat Exchangers
• Power Generation Plants
• High-Temperature Chemical Processing

Quality Testing

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

Conclusion

ASTM A358 EFW 321H Pipes deliver enhanced high-temperature strength, excellent oxidation resistance, and stable welded construction. Their high-carbon titanium-stabilized composition makes them ideal for critical elevated temperature industrial applications.