What are the main advantages?
Excellent high temperature strength (strength is twice that of 20# steel at 500℃), strong oxidation resistance (weight gain ≤2g/m²·h at 540℃), mature welding process, high cost performance (price is only 1/3 of P91). Suitable for key components at medium temperature and medium pressure, with comprehensive performance better than ordinary alloy steel.
What are the limitations?
High temperature endurance strength is lower than that of 9Cr steel (such as P91), and the creep rate rises sharply above 550℃. Molybdenum element leads to temper brittleness tendency (impact value decreases after long-term operation at 350℃~575℃), and cold working is prone to cracking, requiring strict heat treatment system.
How does it compare with similar foreign materials (such as P11)?
ASTM A335 P11 (1.25Cr-0.5Mo) has a composition close to 15CrMo, but Cr is slightly higher (1.00%~1.50%). P11 requires higher impact energy (≥41J vs. ≥34J for 15CrMo). 15CrMo can be equivalent to P11, but additional inspection is required according to ASME SA335 standard.
What are the degradation problems in long-term service?
Common problems include: pearlite spheroidization (degradation to level 4 after 20,000 hours above 500℃), graphitization (risk of exceeding 100,000 hours), and temper brittleness. Regular metallographic inspection is required, and replacement is mandatory when spheroidization reaches level 5 or impact energy decreases by 30%.
How is the economic efficiency?
The material cost is about 8,000~10,000 yuan/ton (2024), which is 15% lower than 12Cr1MoV, and the processing fee is 20% higher (due to strict heat treatment). The full life cycle cost is lower than carbon steel (extending the replacement cycle), but higher than high alloy steel (such as increased energy consumption when the operating temperature exceeds 540℃).
