What is the chemical composition of 15CrMo steel pipe?
15CrMo is a low alloy chromium-molybdenum steel, the main components of which are: carbon (C: 0.12%~0.18%), chromium (Cr: 0.80%~1.20%), molybdenum (Mo: 0.40%~0.55%), manganese (Mn: 0.40%~0.70%), silicon (Si: 0.17%~0.37%). Phosphorus and sulfur impurities are controlled at ≤0.035%. The chromium-molybdenum combination gives it excellent high-temperature strength and oxidation resistance, and the carbon content balances toughness and hardness, making it suitable for high-temperature environments below 540°C.
What are the mechanical properties of 15CrMo steel pipe?
After normalizing + tempering heat treatment, the typical mechanical properties of 15CrMo steel pipe are: tensile strength ≥440 MPa, yield strength ≥295 MPa, elongation ≥22%, impact energy ≥55J (room temperature), hardness ≤179 HB. The endurance strength at high temperature (500℃) is still ≥110 MPa, which is better than ordinary carbon steel and meets the long-term pressure requirements of boilers and pressure vessels.
What temperature environments are 15CrMo steel pipes suitable for?
The design operating temperature of 15CrMo is -20℃~550℃, and it still maintains high creep strength in the range of 450℃~540℃. It is suitable for high temperature scenes such as power station boiler superheater tubes and petrochemical cracking furnace tubes. Impact tests are required in low temperature environments (such as -20℃ KV2≥34J) to avoid cold brittle fracture. When the oxidation resistance exceeds 550℃, it is recommended to use high alloy steels such as 12Cr1MoV.
What is the difference between 15CrMo and 12Cr1MoV?
15CrMo contains less chromium and molybdenum (Cr≤1.2%, Mo≤0.55%), while 12Cr1MoV adds vanadium (V: 0.15%~0.30%) and has stronger heat resistance (operating temperature up to 580℃). 15CrMo has better weldability and lower cost; 12Cr1MoV has higher high temperature strength but is prone to reheat cracking. Select materials according to working conditions: 15CrMo below 540℃, 12Cr1MoV at higher temperatures.
How is the corrosion resistance of 15CrMo steel pipe?
Chromium forms a dense oxide film (Cr₂O₃) that can resist steam and weak acid and alkali corrosion, but is prone to high-temperature sulfur corrosion in sulfur-containing flue gas (such as coal-fired boilers). Chloride ion environments (such as offshore platforms) may cause stress corrosion cracking (SCC), and the medium composition needs to be strictly controlled. It is recommended to perform surface aluminization or apply anti-corrosion coating in an acidic environment.
