ASME SA312 347H is an austenitic stainless steel whose core advantages lie in its superior high-temperature strength, excellent oxidation resistance, and outstanding resistance to intergranular corrosion.
This material is specifically designed for high-temperature and high-pressure environments, maintaining high mechanical strength and stable oxidation resistance within a temperature range of 600°C to 800°C, making it particularly suitable for thermal cycling.
Therefore, ASME SA312 347H is widely used in petrochemical, nuclear power, large power plant boilers, and heat exchangers, making it a crucial material choice for high-temperature and high-pressure piping systems.
ASME SA312 347H Seamless Pipe Material Specification
The following is a table of main specifications for ASME SA312 347H stainless steel seamless tubes.
|
Product Standards |
ASME SA312 (or equivalent ASTM A312) |
|
Material Grade |
TP347H (UNS S34709) |
|
Type |
Seamless (SMLS) |
|
Chemical Composition |
Carbon (C): 0.04-0.10%, Chromium (Cr): 17.00-19.00%, Nickel (Ni): 9.00-13.00%, Niobium (Nb): ≥8×C%, Manganese (Mn) ≤2.0%, Silicon (Si) ≤1.0%, Phosphorus (P) ≤0.045%, Sulfur (S) ≤0.03%, Iron (Fe) Balance |
|
Mechanical Properties |
Tensile Strength ≥515 MPa, Yield Strength ≥205 MPa, Elongation ≥35% |
|
Physical Properties |
Density ~7.96 g/cm³, Melting Point ~1454°C |
|
Outer Diameter Range |
Seamless Tube: 1/2 inch to 24 inches (or 6 mm to 630 mm) OD) |
|
Wall Thickness Grade |
SCH 5S, 10, 10S, 20, 30, 40, STD, 40S, 60, 80, XS, 80S, 100, 120, 140, 160, XXS, etc. |
|
Manufacturing Process |
Hot-rolled, cold-rolled, cold-drawn |
|
Heat Treatment Condition |
Solution treatment (annealing), temperature not lower than 1040°C |
|
Main Applications |
Boiler tubes, superheaters, high-temperature chemical processing, petroleum refining, heat exchangers, high-temperature steam pipelines, etc. |
Type of A312 TP347H Stainless Steel Pipe
Classification by Manufacturing Process
347H seamless steel pipes are formed by piercing blanks and then cold drawing or cold rolling, without weld seams. This manufacturing process gives them uniform circumferential mechanical properties, enabling them to withstand higher pressures and mechanical stresses.
Therefore, seamless pipes are particularly suitable for critical high-temperature and high-pressure applications, such as superheaters and reheaters in power plant boilers, and high-temperature and high-pressure pipelines in the petrochemical industry.
The disadvantages are relatively high production costs, and the technical difficulty in producing large-diameter, ultra-thin-walled pipes, with the risk of cold-drawing fracture.
347H welded steel pipes are made by rolling and welding TP347H steel plates or strips using various welding methods. Welded pipes have higher production efficiency, lower costs, and can produce large-diameter pipes.
Common welding methods include TIG, MIG, and high-frequency resistance welding used for manufacturing finned tube base pipes.
These are commonly used in heat exchangers, condensers, certain structural components, and water filtration systems in power systems-applications where pressure and temperature requirements are not extremely stringent.
Classification by Product Form
TP347H finned tubes are specially processed products, significantly increasing their external surface area by welding spiral or longitudinal fins onto the outer wall of the tube.
This design greatly improves heat exchange efficiency. Due to their excellent high-temperature strength and oxidation resistance, TP347H finned tubes are commonly used in boilers, air preheaters, industrial furnaces, and various high-efficiency heat exchangers.
With proper maintenance, these finned tubes have a design life of over 20 years.
347H plain tubes with smooth inner and outer walls, are the most widely used form. They are supplied in standard sizes and can also be customized to customer needs, including specific outer diameters, wall thicknesses, and cut to length.
Price of A312 TP347H Stainless Steel Pipe
The prices for ASTM A312 TP347H stainless steel seamless pipes in 2025 are as follows.
|
Price Categories |
Price (USD) |
Units |
|
Market Average Price |
2,500 - 4,100 |
ton |
|
Common Price Quotes |
500 - 3,000 |
ton |
|
High-End Precision Tubes |
6,000 - 15,000 |
ton |
|
Price Per Kilogram |
1.5 - 9 |
kilogram |
|
Large Diameter Tubes |
About 4,500 |
ton |
|
Cold-Drawn Tubes |
3,000 - 5,000 |
ton |
The price fluctuation of ASTM A312 TP347H stainless steel pipe is mainly influenced by the following factors:
First, raw material costs are crucial. As a high-performance austenitic stainless steel, its price is closely linked to the global market prices of alloying elements such as nickel, chromium, and niobium.
Second, manufacturing processes and specifications, such as seamless cold drawing or hot rolling, product diameter and wall thickness, and whether high-precision tolerances are required, all significantly increase production costs.
Third, order size and supply chain factors play a role. Larger-volume purchases typically yield better unit prices, while logistics costs and supplier inventory levels also affect the final quote.
Finally, quality certifications and additional services, such as requiring special third-party certifications, stringent material testing reports, or additional surface treatments, all incur additional costs.
ASME SA312 347H Stainless Steel Pipe Applications
Energy and Power Industry
In the energy and power sector, this material is a key component in the manufacture of superheater tubes, reheater tubes, and main steam pipes for supercritical boilers.
Its excellent high-temperature strength and creep resistance allow it to operate stably for extended periods under high temperature and pressure conditions exceeding 650°C, making it commonly used in thermal and nuclear power projects.
Petrochemical and Refining Industries
In the petrochemical and refining industries, TP347H steel pipes are widely used in corrosion-resistant components such as refining units, heat exchanger tubes, and reactors in chemical equipment.
It effectively resists corrosive media such as acids, alkalis, and salts, and is suitable for high-temperature and high-pressure process environments.
Special Industrial Environments
Furthermore, this material is also used in the inlet piping systems of hydrogen production converters, flue gas desulfurization units in power plants, and high-temperature equipment in industries such as synthetic fibers and papermaking.
It exhibits good resistance to intergranular stress corrosion caused by polysulfides, making it suitable for harsher operating environments.
