ASTM A358 TP304H Class 1 Stainless Steel EFW Pipe

What is ASTM A358 material?

ASTM A358 is a standard specification for Electric-Fusion-Welded (EFW) austenitic chromium-nickel stainless steel pipes. These pipes are fabricated from steel plates using filler metal and are specially designed for high-temperature service and general corrosive environments.

 

ASTM A358 TP304H EFW Pipe Manufacturer , Supplier, Exporter, Stockist

GNEE has over 18 years of experience in manufacturing stainless steel pressure piping, focusing on the production of double-welded EFW (Electric-Fusion-Welded) pipes that fully comply with the ASTM A358 Class 1 TP304H standard, which are widely used in power plant boilers, petrochemical high-temperature pressure piping, and ASME B31.3 critical process piping.

 

GNEE produces ASTM A358 Class 1 TP304H EFW steel pipes utilizing UNS S30409 stainless steel plates verified by PMI spectroscopy, which are precision cut, bevel ground, and roll-formed into cylindrical shells. To strictly satisfy the mandatory Class 1 manufacturing standard, we execute a double-welded process utilizing filler metal for all passes, and perform 100% full-length Radiographic Testing (RT) on every weld seam, eliminating the spot-check inspection method typical of Class 5 products.

 

All TP304H EFW pipes are subjected to post-weld full solution annealing at 1100–1150℃ to eliminate weld-induced carbide precipitation; subsequently, they undergo hydrostatic testing at 2 times the rated working pressure, as well as full-length Eddy Current Testing (ECT), transverse tensile tests, and guided-bend tests. Our batch delivery weld acceptance rate reaches as high as 99.97%, far exceeding the large-diameter EFW piping industry average of 98.5%.

 

When operating continuously at a temperature of 650℃, the creep-rupture strength of ASTM A358 Class 1 TP304H steel pipes is 32% higher than standard TP304, supporting long-term stable operation under high-temperature conditions of 520–810℃, making them suitable for superheater and reheater piping systems.

 

We supply ASTM A358 TP304H steel pipes covering outside diameters of 10.3–2032mm (NPS 1/8″–80″) and wall thicknesses of SCH5–SCH160 (1–60mm); dimensional tolerances are strictly controlled within ±0.4% for outside diameter and ±5% for wall thickness; we support 1–12.5m cut-to-length customization and provide machined beveled ends conforming to the ASME B36.19 standard.

beveled ends

 

ASTM A358 TP304H Pipe Specification

 

Chemical Composition (Weight %)

Grade	UNS	C	Mn (max)	P (max)	S (max)	Si (max)	Cr	Ni
TP304H	S30409	0.04 – 0.10	2.00	0.045	0.030	1.00	18.0 – 20.0	8.0 – 11.0

 

Mechanical & Physical Properties (At Room Temperature)

Grade	Tensile Strength (min)	Yield Strength 0.2% (min)	Elongation in 2" (min)	Hardness (max)
TP304H	75 ksi (515 MPa)	30 ksi (205 MPa)	35%	192 HBW / 90 HRB

 

Heat Treatment Requirements

Grade	Heat Treatment Type	Temperature (min)	Quenching Media
TP304H	Solution Annealing	1900°F (1040°C)	Water or rapid cooling by other means

 

ASTM A358 Class 1 vs Class 5

Class	Welding Method	Radiography	Description
Class 1	Double welded by filler metal	100% Radiographed	All welds completely examined by X-ray.
Class 2	Double welded by filler metal	None	No radiography required.
Class 3	Single welded by filler metal	100% Radiographed	Single-pass welding with full X-ray.
Class 4	Single welded by filler metal	None	Single-pass welding; no X-ray (Last pass can be without filler).
Class 5	Double welded by filler metal	Spot Radiographed	Spot X-ray examination according to code.

 

ASTM A358 Pipe Dimensional Tolerances

Feature	Parameter	Tolerance
Outside Diameter (OD)	1/8" to 1-1/2" (incl.)	±1/64" (0.4 mm)
	Over 1-1/2" to 4" (incl.)	±1/32" (0.8 mm)
	Over 4" to 8" (incl.)	±1/16" (1.6 mm)
Wall Thickness	Any Size	-12.5% of nominal thickness (no upper limit for EFW)
Weight	All sizes	+10% / -3.5%

 

Applications of ASTM A358 Grade TP304H (UNS S30409) Pipe

Power Generation: Used in fossil-fuel and nuclear power plants for high-pressure boiler tubes, steam piping, superheater headers, and reheater piping.
Petrochemical and Refining: Used for fluid piping, reaction vessels, and piping systems in refineries and petrochemical processing facilities that must withstand high temperatures and corrosive by-products.
Chemical Processing: A key material for manufacturing heat exchangers and condenser tubes, as well as process piping used to handle corrosive acids and high-temperature gases.

 

ASTM A358 TP304H Pipe Stock Available

Regarding certifications and supply capabilities, GNEE holds a comprehensive suite of credentials, including ISO9001, SGS, CE, and PMI material verification. The company maintains a standing inventory of 100 tons of finished TP304H grade piping and 200 tons of certified TP304H plate, enabling shipment of stock items within 7 days and delivery of custom orders within 28 days.

Click Here to Check Our ASTM A358 TP304H Stainless Steel Pipe Stock

ASTM A358 TP304H Pipe Price

The price for ASTM A358 TP304H (Electric Fusion Welded) stainless steel pipe typically ranges from $3,200 to $4,700 USD per metric ton, which translates to roughly $3.20 to $4.70 per pound.

 

Testing and Inspection Requirements

Test Item	Standard Reference	Purpose
Hydrostatic Test	ASTM A999	Ensures pressure integrity (mandatory unless NDT is specified).
Transverse Tension Test	ASTM A358	Verifies the strength of the base metal and the weld seam.
Transverse Guided-Bend Test	ASTM A358	Checks the ductility and fusion quality of the weld.
Radiographic Exam (RT)	ASME BPVC Sec. VIII	Required for Class 1, 3, and 5 to detect internal defects.
Visual/Dimensional	MSS SP-55 / ASTM A999	Checks for surface defects, diameter, and wall thickness.

Packing & Loading

There are probably hundreds of different methods for packing a pipe, and most of them have merit, but there are two principles that are vital for any method to work prevent rusting and Sea transportation security. Our ASTM A358 TP 304L Stainless Steel EFW pipes packing can meet any needs of the customers.
1.Bundle packing
2.Crate packing
3. Naked packing
4.Protect by wood at both ends

FAQ

What filler metal is used for welding A358 TP304H pipe?
When welding ASTM A358 TP304H, a filler metal matching the base metal's properties must be used; ER308H or E308H is typically recommended.
Note: The use of 308L filler metal as a substitute is strictly prohibited, as a low-carbon weld seam would significantly reduce the overall pipe's strength at high temperatures.

 

What is the grain size of A358 TP304H?
According to the ASTM A358 specification, TP304H must meet specific grain size requirements (typically ASTM No. 7 or coarser).

 

What does the "H" in TP304H stand for?
The "H" stands for "High Carbon"; the carbon content of TP304H must be controlled within the range of 0.04% to 0.10%. While TP304 (carbon content ≤0.08%) and TP304L (carbon content ≤0.03%) are primarily used for corrosion resistance, TP304H is specifically designed for high-temperature environments (typically above 525°C). The higher carbon content provides superior creep strength, making the pipe less prone to deformation or rupture at high temperatures.