ASTM A213 / ASME SA213 TP347 Stainless Steel Seamless Heat Exchanger Tube

ASTM A213 / ASME SA213 TP347 Stainless Steel Seamless Heat Exchanger Tube

ASTM A213 / ASME SA213 specification covers seamless ferritic and austenitic steel boiler, superheater and heat exchanger tubes. TP347 is an important material under this standard and is commonly used in heat transfer equipment such as boilers, reheaters, superheaters and heat exchangers. ASTM A213 /ASME SA213 TP347 heat exchanger tube is an austenitic stainless steel with a face-centered cubic structure. It is usually non-magnetic and may have weak magnetism after cold working. It can be used in high temperature environments and has excellent oxidation resistance, toughness, formability and weldability.

Chemical Composition of TP347 Stainless Steel Heat Exchanger Tube Boiler Tube

ASTM A213 TP347 stainless steel heat exchanger tube has top-level intergranular corrosion resistance, excellent welding condition, high reliability in sensitized environments such as welding heat affected zone, excellent high temperature strength, high temperature oxidation resistance and resistance to multiple corrosion, can adapt to harsh combustion and chemical environments, and is an irreplaceable material in the high temperature section. 

However, it should be noted during use that the cost of ASTM A213 TP347 is significantly higher than that of ferritic alloy steels such as T5 and T9, and the thermal expansion coefficient is higher, which will produce higher thermal stress and thermal fatigue sensitivity. At the same time, the thermal conductivity is low and the thermal conductivity is poor. It should avoid aqueous solutions or steam environments containing chloride ions to reduce the risk of chloride stress corrosion cracking. The welding process must be strictly controlled during welding to reduce the tendency of thermal cracking.

When choosing to use TP347 or TP347H heat exchange tubes, the decision is mainly based on the design temperature of the specific equipment and the life requirements of the heat exchange tubes. As mentioned above, the difference between TP347 and TP347H heat exchange tubes lies mainly in the carbon content. The upper limit of the carbon content of TP347 is 0.08%, and the "H" in TP347H stands for High Temperature. Its carbon content is usually 0.04% - 0.10%. The higher carbon content can make the heat exchange tube precipitate fine niobium carbide or carbon chromium compounds at higher temperatures, which can make the heat exchange tube have higher high temperature creep rupture strength. It is specially designed for heat exchange tubes used in high temperature environments for a long time.

ASTM A213/ASME SA213 TP347 Application Scenarios

• Welded parts or parts that cannot be solution treated after welding: Because TP347H has strong anti-sensitization ability, unless there are special requirements or severe deformation, it is usually not necessary to perform solution annealing like 304 to restore corrosion resistance after welding.
• Equipment exposed to the sensitization temperature range (425-860°C) for a long time: such as some heat exchange equipment.
• Higher temperature areas requiring higher creep strength: TP347H is usually selected. For example, high-temperature superheaters and reheaters of modern ultra-supercritical (USC) power plant boilers.
• Environments exposed to certain specific corrosive media: such as nitric acid, organic acids, etc.