Effect of solution cooling methods on properties and residual stress of GH4096 alloy

Abstract

In order to ensure the main mechanical properties of GH4096 alloy, reduce the internal residual stress of forgings for thin-walled parts and improve the dimensional control accuracy of parts machining, the effect of air cooling (AC), wind cooling (WC), oil cooling (OC) and salt bath cooling (SC) after solution heat treatment on the size, morphology of precipitated phase, mechanical properties and internal residual stress of GH4096 alloy ring forgings was studied. The results show that the secondary and tertiary γ′ phases of the air-cooled sample are coarser than those of the traditional oil-cooled sample, and the creep and high-temperature tensile properties are greatly reduced. The size of the secondary γ' phase is slightly increased, the size of the third γ' phase is equivalent of wind cooled sample, and the creep and high-temperature tensile properties are slightly reduced. The size of the secondary and tertiary γ' phase of the salt bath cooled sample is equivalent, so the difference of creep and high-temperature tensile properties is small. The residual stress in the samples by wind cooling could be controlled within ±100 MPa, which was more than 50% lower than that in the samples by oil cooling and salt bath cooling. The residual stress of the ring forgings by air cooling is lower than that of the ring forgings by oil cooling and salt bath cooling, and the main mechanical properties are only slightly reduced. It is helpful to improve the deformation of GH4096 alloy thin-walled parts during cold machining and improve the dimensional accuracy.

Keywords

• gh4096
• solution cooling method
• mechanical properties
• residual stress