Aging heat treatment method of precipitation strengthening type nickel-based superalloy welded joint for aero-engine case

Abstract

The invention discloses an aging heat treatment method of a precipitation strengthening type nickel-based superalloy welded joint for an aero-engine case. The aging heat treatment method comprises the following steps of (1) first-stage aging: putting the joint into a heating furnace at 770-830 DEG C, and preserving heat for 8-12 hours; (2) second-stage aging: reducing the furnace temperature to 770-830 DEG C according to a speed of 50-70 DEG C/h, and preserving heat for 8-12 hours; and (3) third-stage aging: reducing the furnace temperature to 600-650 DEG C according to a speed of 50-70 DEG C/h, and preserving heat for 8-12 hours. According to the aging heat treatment method, aging heat treatment is conducted in a stepped cooling and heat preservation mode, the alloy structure is greatly improved, the residual stress in the welded joint is effectively reduced, and the performance of the welded joint of the engine case and the service safety of the welded joint are improved.

Description

technical field [0001] The application relates to the field of engine manufacturing, in particular to an aging heat treatment method for a precipitation-strengthened nickel-based superalloy welded joint for an aero-engine case. Background technique [0002] Since improving engine performance requires improving the engine’s temperature-bearing capacity, aero-engine casings generally use precipitation-strengthened nickel-based superalloys. This alloy has good mechanical properties and high-temperature oxidation resistance at high temperatures, but the welding In the process, the weld metal is often re-melted and combined, the microstructure and precipitated phases will also change, the heat-affected zone of the base metal will also form a gradient structure, and the residual stress distribution of the welded joint is not uniform. These factors will lead to welded joints. Performance drops. Contents of the invention [0003] The object of the present invention is to provide ...

AI Technical Summary

Problems solved by technology

[0002] Since improving engine performance requires increasing the engine’s temperature-bearing capacity, aero-engine casings generally use precipitation-strengthened nickel-based superalloys, which have good mechanical properties and high-temperature oxidation resistance at high temperatures. Often accompanied by the re-melting of weld metal, the microstructure and precipitated phases will also change, the heat-affected zone of the base metal will also form a gradient structure, and the residual stress distribution of the welded joint is not uniform. performance drop