ASTM A358 TP347H EFW Stainless Steel Pipe

Gnee Steel (Tianjin) Co., Ltd. is one of the most professional manufacturers and suppliers of ASTM A358 TP347H EFW Stainless Steel Pipe in China. With abundant experience, we warmly welcome you to wholesale customized ASTM A358 TP347H EFW Stainless Steel Pipe from our factory. For price consultation, contact us.

If you are looking for large-diameter, heavy-wall process piping capable of long-term, stable operation under high-temperature, high-pressure, severe thermal cycling, and harsh corrosive conditions, ASTM A358 TP347H double automatic electric-fusion-welded (EFW) stainless steel pipe is the ideal choice for petrochemical, hydrocracking, supercritical power generation, and nuclear power industries.

What is ASTM A358 TP347H welded pipe?

ASTM A358 TP347H is an electric-fusion-welded austenitic stainless steel pipe designed specifically for high-temperature and corrosive industrial service. It features a controlled higher carbon content (0.04% to 0.10%) alongside niobium (Nb) stabilization, demonstrating exceptional creep resistance at temperatures above 1000°F (538°C),approximately 20% higher than 304H,with a continuous anti-oxidation operating temperature reaching up to 850°C.

ASTM A358 TP347H Stainless Steel EFW Pipes Supplier

The ASTM A358 TP347H EFW pipes we supply are manufactured using a double automatic electric fusion welding (Double Welded / Class 1) process, with 100% radiographic testing (RT) inspection on the weld seam to achieve a joint factor of 1.0. Delivering a minimum tensile strength of 515 MPa, a yield strength of 205 MPa, and an elongation of ≥ 35%, they provide an exceptionally high pressure-bearing safety margin and superior resistance to thermal fatigue cracking.

GNEE can supply ASTM A358 TP347H pipes with outer diameters ranging from 8" to 72" (DN200–DN1800) and wall thicknesses from SCH 10S to SCH 160/XXS (2.0 mm to 50 mm), with single lengths up to 12 meters. All pipes undergo mandatory solution annealing at a minimum of 1040°C followed by rapid quenching. We also support pipe-end beveling, large-diameter custom bend fabrication, and non-standard wall thickness customization. Every batch passes 100% hydrostatic testing and weld seam RT non-destructive testing, accompanied by EN 10204 3.1 / 3.2 Mill Test Certificates.

ASTM A358 TP347H Pipe with 100% RT Testing

ASTM A358 TP347H Large Diameter Double Welded Pipe

Test Item	Description
Transverse Tension Test	One test is required to check the tensile properties across the weld.
Transverse Guided-Bend Weld Test	Ensures the ductility and soundness of the weld joint.
Hydrostatic Test	100% of pipes must be tested unless NDT (like Eddy Current) is performed.
Radiographic Examination (RT)	Mandatory for Class 1 (100% of weld length) to detect internal defects.
Visual Examination	Pipe shall be free from scale and contaminating exogenous iron particles.

Radiographic Examination (RT)

Transverse Tension Test

High-quality export packaging

ASTM A358 TP347H Stainless Steel Double Welded Pipes are packed with strict protection for large-diameter export transportation. Each pipe is fitted with protective end caps, separated with soft materials, and wrapped with waterproof film to prevent moisture, scratches, and surface contamination. Pipes are secured on steel frames or reinforced wooden supports, with each bundle clearly marked with grade, OD, wall thickness, length, heat number, and quantity. Export packaging is suitable for 20-ft and 40-ft containers, with customized packing available for pipes up to 12 m long and 72" OD.

Q1: What is the difference between ASTM A358 and ASTM A312?

A:

ASTM A358 is a standard for electric-fusion-welded (EFW) stainless steel pipe, typically fabricated from steel plate (ASTM A240) by rolling and welding. It is designed for large-diameter, high-temperature service and permits the addition of filler metal.

ASTM A312 is a standard for general industrial stainless steel pipe (seamless or automatically welded), typically produced in smaller diameters without the addition of filler metal (autogenous welding).

Q2: What is the difference between TP347H and TP347?

A: The "H" designation stands for High Carbon.

Carbon Content: TP347H requires a carbon content controlled between 0.04% and 0.10%, whereas standard TP347 has a upper carbon limit capped at 0.08% max. TP347H provides significantly higher creep strength in operating environments above 1000°F (538°C).

Q3: How should the Class designation be selected when purchasing A358 TP347H?

A:

Class 1 (Double welded + 100% RT): Must be selected for extreme high-pressure or critical service applications, such as nuclear power piping and main steam lines.

Class 2 (Double welded, no RT required, hydrostatic tested): May be chosen for general high-temperature conveyance where budget constraints exist.

Class 3 / Class 4 (Single welded): Typically used for lower pressure applications.

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