Influence of 12Cr1MoV Material on Tissue Properties at High Temperature and Long Operating Time

Abstract

12Cr1MoV is commonly used for pressure pipes in thermal power plants. However, its service life has always prevented the development of such metallic materials. This experiment applies a tensile and impact experiment to investigate the metal cluster of 12Cr1MoV low-alloy and heat-resistant steel with 60,000 h service at 550 °C. Results indicate that, after 60,000 h of high-temperature exposure, the metal cluster of Cr, Mo, and V elements may gradually decrease. First, the decreasing elements will precipitate out of the solid solution. Then, the precipitated elements transform into carbides that accumulate and grow on the grain boundaries. The continuous growth of the precipitated carbide of alloy elements may also create pearlite in the cluster, which results in severe pearlite periodization and tensile fracture due to plastic, through-crystal fracture. Then, the solid solution-strengthened tissue disappears, which severely decreases the thermal strength of 12Cr1MoV low-alloy and heat-resistant steel. At the same time, the brittleness of the steel will increase. The end of life of the metal occurs after 60,000 h of high-temperature use at 550 °C. This result may also provide a basis for future life assessment of 12Cr1MoV steel.