15CrMoG seamless steel pipe

15CrMoG seamless steel pipe is a chromium-molybdenum alloy steel pipe widely used in high-temperature and high-pressure applications. Thanks to its outstanding strength, oxidation resistance, and stability, it has become a critical material in industries such as power generation, petrochemicals, and boiler manufacturing.

Chemical Composition of 15CrMoG Seamless Steel Pipe

The primary alloying elements of 15CrMoG steel are chromium (1.00–1.50%) and molybdenum (0.45–0.65%).

Chromium forms a dense oxide layer that protects against further oxidation.

Molybdenum enhances hot strength and creep resistance, ensuring the pipe maintains stability at elevated temperatures.

Additional elements—carbon, silicon, manganese, phosphorus, and sulfur—are carefully controlled to balance overall performance.

This alloy design enables the pipe to combine strength, durability, and corrosion resistance in extreme environments.

Production Process of 15CrMoG Seamless Steel Pipe

15CrMoG seamless steel pipes are typically produced via hot rolling or cold drawing:

Hot rolling: Steel billets are heated, pierced, and rolled into pipes, offering high efficiency for mass production.

Cold drawing: Hot-rolled billets are drawn through dies at room temperature, resulting in higher precision and superior surface quality.

To achieve optimal microstructure and mechanical performance, the pipes undergo heat treatments such as normalizing and tempering. Strict control of parameters such as temperature and deformation is essential to ensure compliance with standards.

Mechanical & Physical Properties of 15CrMoG Seamless Steel Pipe

Tensile strength: 440–640 MPa

Yield strength: ≥295 MPa

Elongation: ≥21%

High-temperature resistance: Stable below 500 °C, short-term use up to 550 °C

Creep resistance: Excellent under prolonged high-temperature stress

Thermal expansion coefficient: ~12.5 × 10⁻⁶/°C

Thermal conductivity: 42.7 W/(m·K)

These properties make the pipe highly reliable in demanding high-pressure and high-heat systems.

Key Applications of 15CrMoG Seamless Steel Pipe

Power generation – widely used in superheaters, reheaters, and main steam lines of supercritical and ultra-supercritical boilers.

Petrochemical industry – applied in hydrogenation reactors, catalytic cracking units, and other high-pressure, high-temperature equipment.

Boiler manufacturing – standard choice for high-pressure boiler heating surfaces.

Other industries – nuclear power, metallurgy, and machinery manufacturing.

15CrMoG is chosen where long-term stability under extreme stress is required.

Comparison with Other Steels

Vs. carbon steel:

2–3× higher allowable stress at the same temperature

Superior oxidation resistance → longer service life

Greater structural stability → less prone to pearlite spheroidization

Vs. 12Cr1MoVG:

Lower alloy content → cost advantage

Adequate for most medium-temperature, high-pressure conditions

Vs. P91/P92 steels:

Slightly lower high-temperature strength

Better weldability and processability, making it suitable for specific applications

Welding Considerations of 15CrMoG Seamless Steel Pipe

Due to its alloy content, 15CrMoG is prone to cold cracking during welding. Best practices include:

Preheating: 150–200 °C

Interpass temperature: ≤300 °C

Post-weld tempering: 680–720 °C to relieve residual stresses

Welding materials: Electrodes or wires matching the base metal (e.g., E5515-B2)

Controlled heat input: Prevents overheating and performance loss in the weld zone

Market Outlook of 15CrMoG Seamless Steel Pipe

The demand for 15CrMoG seamless steel pipes continues to grow with the advancement of supercritical and ultra-supercritical power technologies and the expansion of the petrochemical sector. Domestic production capacity has improved, with many products now meeting international standards and entering global markets.

Future developments in material technology are expected to enhance its performance further and broaden its applications.

Maintenance & Storage of 15CrMoG Seamless Steel Pipe

Regular inspections are essential for pipes in continuous high-temperature and high-pressure service.

Watch for wall thinning, oxidation, and structural degradation.

Store in dry environments to avoid rust and protect from impact during transportation.

Proper maintenance can extend service life and ensure operational safety.

Conclusion

15CrMoG seamless steel pipe is a reliable and cost-effective alloy steel pipe designed for high-temperature and high-pressure environments. With its balanced composition, advanced production process, and proven performance, it remains indispensable in modern industry. As technology advances, it is expected to play an even greater role in ensuring the safe, efficient, and sustainable operation of critical equipment worldwide.