ASTM A213 TP202 Stainless Steel Seamless Pipes

It must be clearly stated that TP202 (UNS S20200) is not a standard or common grade within the ASTM A213 specification. ASTM A213 primarily covers specific alloys designed for high-temperature and high-pressure service, such as:

Austenitic Stainless Steels: TP304/H, TP316/H, TP321/H, TP347/H, etc.

Ferritic/Martensitic Alloy Steels: T2, T5, T9, T11, T12, T22, T91, T92, etc.

TP202, as an economical chromium-nickel-manganese (Cr-Ni-Mn) austenitic stainless steel, is initially designed to provide good formability and moderate corrosion resistance at ambient to moderate temperatures, rather than exceptional high-temperature creep-rupture strength and oxidation resistance. Therefore, it is very rarely selected for manufacturing boiler or superheater tubes that must withstand extremely high thermal loads and pressures.

If considered for heat exchange applications, its potential characteristics and limitations are as follows:

Material Characteristics and Limitations

With reference to its general material properties (based on descriptions in the A312 standard), the chemical composition of TP202 (typically ~18% Chromium, 5% Nickel, 8% Manganese) defines the following traits:

Moderate Corrosion Resistance: Better than carbon steel but significantly inferior to TP304. Particularly sensitive to chloride-induced pitting and stress corrosion cracking due to the absence of molybdenum.

Good Ambient Temperature Mechanical Properties and Formability: Strength can be increased through cold work hardening.

Limited High-Temperature Performance: Its high-temperature strength, creep resistance, and oxidation resistance (scaling) are far below those of grades specifically designed for elevated temperatures within ASTM A213 (e.g., TP304H, TP321H). Long-term use above approximately 300°C may pose risks.

Economy: Its main advantage is lower cost compared to standard 18-8 stainless steels (e.g., TP304).

Potential Application Areas (Non-typical Boiler Applications)

Based on its economy and basic properties, it might be considered for some non-critical or low-temperature heat exchange applications:

Low-pressure, low-temperature heat exchangers or heating coils where the medium is not highly corrosive.

Low-temperature piping for industrial or building heating systems.

Low-temperature section components of general heat recovery units.

Standards and Quality Assurance (If manufactured per A213)

If TP202 steel tubes are specially ordered and produced according to the ASTM A213 standard, their inspection would follow the stringent requirements of that specification:

Chemical Composition: Must meet the composition ranges specified by the standard or purchase agreement.

Mechanical Properties: Room temperature tensile testing is performed.

Hardness Test: Hardness testing may be required.

Hydrostatic Test: Each tube undergoes a hydrostatic pressure test.

Non-Destructive Examination: Typically requires eddy current testing or ultrasonic testing to ensure freedom from defects.

Dimensions and Tolerances: Tolerances for outside diameter, wall thickness, length, and ovality are extremely strict to ensure precise assembly and performance within heat exchanger tube bundles.

High-Temperature Performance Testing (Non-mandatory but critical): For boiler tube applications, verification test reports for the crucial high-temperature creep-rupture strength and oxidation resistance data would need to be provided additionally by the manufacturer.

Chemical Composition

Mechanical Properties