What is the chemical composition of 15CrMoG steel pipe?
The main components of 15CrMoG steel pipe include carbon (0.12%-0.18%), chromium (0.80%-1.20%), molybdenum (0.45%-0.60%), and small amounts of silicon, manganese, phosphorus, and sulfur. The addition of chromium improves the steel's oxidation resistance and high-temperature strength, while molybdenum enhances creep resistance. This composition makes it suitable for high-temperature and high-pressure environments. Compared with other alloy steels, its lower carbon content provides superior weldability. This balanced chemical composition is the key to its superior overall performance.
What are the mechanical properties of 15CrMoG steel pipe?
The tensile strength of this steel pipe is typically between 440-640 MPa, the yield strength is no less than 245 MPa, and the elongation is approximately 21%. It maintains high endurance strength and creep resistance even at high temperatures (e.g., 500°C). Its hardness is controlled to HB ≤ 170, ensuring excellent processability. These mechanical properties make it a preferred material for boilers and pressure vessels. Testing must comply with GB/T 3077.
Why is 15CrMoG steel pipe suitable for high-temperature environments?
The alloying combination of chromium and molybdenum forms a stable oxide film at high temperatures, slowing corrosion. Molybdenum effectively inhibits carbide aggregation and maintains high-temperature strength. Experiments have shown that it maintains stable performance even under long-term use at temperatures below 550°C. Compared to ordinary carbon steel, its high-temperature deformation resistance is significantly improved. This property makes it widely used in superheater piping in power plant boilers.
What is the difference between 15CrMoG steel pipe and 12Cr1MoVG?
Both are chromium-molybdenum alloy steels, but 12Cr1MoVG has a higher chromium content (1.00%-1.50%) and contains vanadium (V) for further grain refinement. 15CrMoG has a slightly higher molybdenum content, resulting in better medium-temperature performance. The welding process for 12Cr1MoVG is more complex, requiring strict control of the preheating temperature. Cost-effectively, 12Cr1MoVG is slightly higher, but it is suitable for boilers with higher specifications. The selection process requires a balance between operating temperature and economic efficiency.
What are the density and thermal conductivity of 15CrMoG steel pipe?
Its density is approximately 7.85 g/cm³, similar to that of ordinary carbon steel, but alloying elements enhance its high-temperature performance. Its thermal conductivity is 45 W/(m·K) at 20°C, decreasing slightly with increasing temperature. This characteristic influences the design of heating rates during hot working. Thermal conductivity is also important in calculating the tube wall temperature distribution in boiler design. Data indicates that its thermal fatigue resistance is superior to that of austenitic stainless steel.
