GH4698 alloy thermal treatment method and application thereof

The invention relates to a thermal treatment technology of GH4698 alloy for refining grains and improving strength and toughness. The technology comprises the following steps of: treating at 900-1,050 DEG C for at least 5 hours, and cooling; performing low-temperature aging treatment at 580-700 DEG C for at least 15 hours, and cooling; and performing once high-temperature aging treatment at 710-810 DEG C for at least 10 hours, and cooling. After the three processes are over, the forging has high strength and good plasticity but relatively bad impact property, thus once aging is finally performed at 780-880 DEG C, the heat is preserved for relatively short time, and then the product is air-cooled to room temperature. After the four processes are over, the grain size of the forging is kept at level 5-6, the grain does not grow bigger, the loss of strength and plasticity is avoided, and the impact toughness is improved relatively greatly. The thermal treatment technology provided by the invention is suitable for all enterprises producing and using GH469 forging, and enables the forging to meet higher requirements on grain refining and high-strength toughness.