High pressure boiler tube material selection

High-pressure boiler tubes are designed to withstand high temperatures and pressures, making them essential in the manufacture of piping systems for high-pressure boilers, nuclear power plants, petrochemicals, ships and other industries. The materials used for high-pressure boiler tubes are carefully selected based on their ability to resist creep, corrosion, and oxidation while maintaining strength at elevated temperatures. Here are some of the common materials used for high-pressure boiler tubes.

1. Carbon Steel (e.g., SA178)
Description: Carbon steel is a basic material used in boiler tube. It offers good strength and moderate corrosion resistance at temperatures up to about 1000°F (540°C).

Applications: Suitable for low to medium pressure applications. Used where the operating temperature is below 800°F (427°C) for rimmed steel and below 1000°F (540°C) for killed steel.

2. Carbon-Molybdenum Steel (e.g., SA209)
Description: Carbon-molybdenum steels typically contain about 0.5% molybdenum, which improves creep strength and corrosion resistance compared to plain carbon steels.
Applications: Commonly used in high-temperature and high-pressure environments, such as in superheaters and reheaters. It can handle temperatures up to 1000°F (540°C).

3. Low Alloy Steel (e.g., SA213-T11, T12, T22)
Description: These steels contain small amounts of chromium (up to 2.25%) and molybdenum (up to 1%), which enhance their strength, creep resistance, and oxidation resistance at high temperatures.

Applications: Frequently used in high-pressure boilers, withstanding temperatures up to 1200°F (650°C). T11 and T12 are suitable for slightly lower temperature applications, while T22 is used for higher temperatures due to its superior creep strength.

4. High Alloy Steel (e.g., SA213-T9, T91)
Description: High alloy steels such as T9 and T91 contain higher levels of chromium (up to 9%) and molybdenum (up to 1%), offering excellent corrosion and oxidation resistance, along with high creep strength.
Applications: Used in superheaters, reheaters, and other components in high-pressure boilers operating at temperatures up to 1200°F (650°C).

5. Stainless Steel (e.g., SA213-T304, T316)
Description: Austenitic stainless steels, such as T304 and T316, offer excellent corrosion and oxidation resistance, high strength, and good ductility. These materials can operate at higher temperatures without losing their mechanical properties.
Applications: Ideal for high-pressure and high-temperature environments, especially where corrosion resistance is critical. Used in superheaters and reheaters, with temperature limits depending on the specific grade, usually up to 1650°F (900°C).

6. Superalloys (e.g., Inconel, Hastelloy)
Description: These are nickel-based alloys designed for extreme conditions. They provide exceptional strength, creep resistance, and corrosion resistance at temperatures exceeding those of traditional steels.
Applications: Used in the most demanding environments within high-pressure boilers, including supercritical and ultra-supercritical boilers, where temperatures can reach up to 1800°F (980°C).

Conclusion:
The selection of material for high-pressure boiler tubes depends on the specific operating conditions, including temperature, pressure, and the presence of corrosive environments. Carbon steel and carbon-molybdenum steels are suitable for moderate conditions, while low and high alloy steels, stainless steels, and superalloys are used for more demanding applications. Proper material selection is essential for ensuring the safety, efficiency, and longevity of high-pressure boilers.

Read more: American standard for low and medium pressure carbon steel boiler tubes