What You Need to Know About High-Performance 15CrMoG Boiler Steel Tubes Under High Temperature and Pressure

1. Chemical Composition of 15CrMoG Boiler Steel Tubes

The main alloying elements are chromium and molybdenum. Chromium content is 0.80%-1.25%, molybdenum content is 0.40%-0.60%, and carbon content is controlled at 0.12%-0.18%. Other common elements include silicon and manganese. Chromium improves the steel's oxidation resistance and corrosion resistance, while molybdenum significantly enhances the steel's strength and creep resistance at high temperatures. Carbon ensures a certain level of hardness and strength.

2. Mechanical Properties of 15CrMoG Boiler Steel Tubes

The tensile strength of 15CrMoG boiler steel tubes is typically in the range of 440-640 MPa. This high tensile strength allows it to withstand the enormous tensile force exerted by the high-pressure steam inside the boiler during operation, preventing the steel tube from breaking and maintaining its integrity.

Yield strength of 15CrMoG boiler steel pipe: The yield strength is not less than 235MPa. This means that before reaching this stress value, the pipe will only undergo elastic deformation. Once this value is exceeded, it enters the plastic deformation stage. To ensure pipe safety, the operating stress is generally much lower than the yield strength.

Elongation of 15CrMoG boiler steel pipe: The elongation after fracture is not less than 21%. Good elongation gives the pipe good plasticity, allowing it to have buffering capacity when encountering sudden impacts and vibrations, preventing brittle fracture.

3. High-temperature performance of 15CrMoG boiler steel pipe

High-temperature creep resistance of 15CrMoG boiler steel pipe: In high-temperature environments, material atoms move slowly, causing the pipe to gradually deform. 15CrMoG can withstand temperatures of around 550℃ for extended periods with a low creep deformation rate, ensuring long-term dimensional stability of the pipe. This is crucial for the long-term stable power generation of power plant boilers.

Oxidation Resistance of 15CrMoG Boiler Steel Pipes: When temperatures rise, metals readily react with oxygen. Under high-temperature conditions, 15CrMoG boiler steel pipes spontaneously form a dense oxide film, slowing further oxidation, maintaining the mechanical properties of the steel pipe, and preventing thinning of the pipe wall due to surface oxidation and peeling.

4. Machining Performance of 15CrMoG Boiler Steel Pipes

Welding Performance of 15CrMoG Boiler Steel Pipes: With appropriate welding processes and electrodes, 15CrMoG boiler steel pipes can achieve high-quality welding. However, due to its alloying elements, preheating is required before welding, and appropriate heat treatment is necessary after welding to eliminate welding stress and ensure that the performance of the weld and heat-affected zone is similar to that of the base material.

Cold Working Performance of 15CrMoG Boiler Steel Pipes: A certain degree of cold working, such as cold bending, is permissible, facilitating on-site adjustments to the pipe routing to fit complex installation layouts. However, after cold working, heat treatment is often required to restore its properties.

5. Application Scenarios of 15CrMoG Boiler Steel Tubes

15CrMoG boiler steel tubes are widely used in the heating surface tubes of power plant boilers, such as water-cooled walls, superheaters, and reheaters. They are also used in key parts such as steam pipelines and headers to transport high-temperature and high-pressure steam, helping thermal power generation to operate efficiently and safely.