15CrMoG seamless steel pipe is a special alloy steel pipe widely used in high-pressure, high-temperature environments. The “15″ in its name represents a carbon content of approximately 0.15%, “Cr” and “Mo” represent the alloying elements chromium and molybdenum, respectively, and “G” designates it as a boiler steel. This material, with its excellent heat resistance, creep resistance, and high-temperature strength, has become a key material in industries such as power generation, petrochemicals, and boiler manufacturing.

First, the Material Properties and Chemical Composition of 15CrMoG Seamless Steel Pipe
The chemical composition of 15CrMoG seamless steel pipe is the foundation of its performance. Its typical composition is: Carbon: 0.12%-0.18%, Silicon: 0.17%-0.37%, Manganese: 0.40%-0.70%, Chromium: 0.80%-1.20%, Molybdenum: 0.45%-0.60%, and sulfur and phosphorus contents are strictly controlled to below 0.035%. The addition of chromium significantly improves the steel’s oxidation and corrosion resistance, while molybdenum enhances the material’s high-temperature strength and creep resistance, enabling it to maintain stable mechanical properties even under long-term operation at temperatures below 580°C. In terms of mechanical properties, 15CrMoG seamless steel pipe typically boasts a tensile strength of ≥440 MPa, a yield strength of ≥295 MPa, and an elongation of ≥22%. Its metallographic structure is pearlite + ferrite. After normalizing and tempering, the grain size becomes more uniform, further enhancing its high-temperature resistance. Compared to ordinary carbon steel, its strength degradation rate at high temperatures is approximately 30% lower, making it an ideal choice for manufacturing superheater and reheater pipes for supercritical boilers.

Second, the production process and technical difficulties of 15CrMoG seamless steel pipes.
The production of 15CrMoG seamless steel pipes requires multiple precision processes, including smelting, piercing, rolling, and heat treatment. Smelting begins in an electric arc furnace or converter, followed by LF furnace refining and VD vacuum degassing to ensure molten steel purity. During the hot rolling process, a piercing mill is used to form the billet into a rough tube, which is then formed on a continuous rolling mill. Temperature control is crucial: the piercing temperature must be maintained at 1200±20°C, and the final rolling temperature must be no less than 900°C to avoid internal cracks and surface defects. The cold working stage utilizes cold rolling or cold drawing, achieving deformation rates of up to 80% to enhance dimensional accuracy. Heat treatment utilizes a dual process of “normalizing (900-930°C) + tempering (680-720°C)” to eliminate processing stress and ensure uniform carbide precipitation. It is important to note that 15CrMoG is sensitive to cooling rates, requiring staged controlled cooling to prevent increased brittleness caused by martensitic transformation. According to the GB5310-2017 standard, 100% of finished products must undergo eddy current testing and ultrasonic testing to ensure the absence of defects such as slag inclusions and pores.

Third, the core application areas of 15CrMoG seamless steel pipes
1. Power Industry: As the “blood vessels” of supercritical boilers, 15CrMoG seamless steel pipes are widely used in superheater piping with steam temperatures reaching 540°C. A 600MW unit requires approximately 200 tons of this material, with a pressure bearing capacity exceeding 28 MPa and a service life exceeding 100,000 hours.
2. Petrochemical Industry: In hydrogenation reactors and cracking units, this material resists H₂S and CO₂ corrosion. A refinery’s hydrocracking unit, using Φ273×28mm pipes, has operated continuously for five years at 450°C and 15 MPa without experiencing hydrogen embrittlement.
3. Nuclear Power Industry: As a secondary circuit auxiliary piping material, its radiation resistance surpasses that of 304 stainless steel. In the Qinshan Nuclear Power Station Phase II project, 15CrMoG pipes account for 18% of the piping system.

Fourth, Industry Standards and Quality Control for 15CrMoG Seamless Steel Pipes
Major domestic and international standards have strict regulations for 15CrMoG:
China’s GB5310-2017 “Seamless Steel Pipes for High-Pressure Boilers” requires a hydrostatic test on each pipe (test pressure = 2.5 x working pressure).
US ASME SA335 requires the Charpy V-notch impact test for chromium-molybdenum steel.
EU EN10216-2 requires high-temperature endurance strength data (generally requiring a 100,000-hour fracture stress ≥ 80 MPa).
In actual procurement, the following quality documents should be of particular interest:
1. Third-party test reports
2. Heat treatment curve records
3. Original non-destructive testing patterns
4. Material traceability codes

Fifth, Market Status and Development Trends of 15CrMoG Seamless Steel Pipes
In 2024, the global 15CrMoG seamless steel pipe market is expected to be approximately 500,000 tons, with China accounting for 65%. Other companies have already achieved full coverage of sizes from 16 to 762 mm, with some products exported to Southeast Asia and the Middle East. As ultra-supercritical units advance toward 630°C, the new, improved 15CrMoG (with trace additions of V and Nb) is currently in the testing phase and is expected to enter mass production in 2026. Regarding maintenance, wall thickness testing is recommended every three years (with particular attention paid to elbows), and replacement should be considered when carbide spheroidization reaches Level 4. During storage, the relative humidity in the warehouse should be maintained at ≤60% to prevent stress corrosion caused by chloride ion environments. As the backbone of industrial high-temperature piping, technological upgrades in 15CrMoG seamless steel pipe will continue to drive energy equipment toward high efficiency and environmental protection. With the increasing prevalence of intelligent manufacturing, production processes will increasingly utilize digital twin technology for quality prediction, further reducing the defect rate to below 0.2%.