Inconel740

The tissue instability of Inconel 740 alloy during long-term aging at high temperature is mainly manifested in the rapid growth of the γ' phase at 750/760°C, the precipitation of the η phase and the formation of the G phase at grain boundaries.

Inconel 740 alloy is an age-hardenable nickel-based high-temperature alloy widely used in advanced ultra-supercritical boiler units operating in an environment of high stress and long-term above 973 K (700°C), where creep is the dominant form of deformation. Due to the long-term exposure to high temperature conditions, a lamellar η phase will form in the alloy, which may adversely affect the creep resistance strength and ductility of the alloy. The microstructural instability of Inconel 740 alloy at high temperatures and long-term aging is mainly manifested by the rapid formation of phases, precipitation and bright G phase at 750/760°C. Adjusting the content of al and TI and reducing the content of SI can significantly improve the microstructure of the alloy. Stability. The absence of T1 and G phases at 750°C and 800°C results in the formation of 740 alloy 740h. Inconel 740/740h has excellent resistance to coal oxidation/fume corrosion and steam oxidation for durability. Machining, welding and fabrication properties are also initially available, making this alloy an important candidate for supercritical power plant boiler over-flow power plant over-flow/heat pipes and thick-walled pipes with steam parameters of 700-750°C.