GH4096合金固溶冷却方式对性能和残余应力的影响

为了在保证GH4096合金主要力学性能的前提下,降低薄壁类零件用锻件的内部残余应力,提高零件加工过程的尺寸控制精度,研究空冷,风冷,油冷,盐浴等固溶冷却方式对GH4096合金环锻件析出相的尺寸和形貌、主要力学性能和内部残余应力的影响。结果表明:与采用传统油冷的试件相比,空冷试件的二次、三次γ′相较为粗大,蠕变性能和高温拉伸性能有较大幅度的降低,风冷试件的二次γ′相尺寸略有增大,三次γ′相尺寸相当,蠕变性能和拉伸性能有小幅降低,盐浴冷却试件的二次、三次γ′相尺寸相当,蠕变性能和拉伸性能相差较小。采用风冷的试件内部残余应力可控制在±100 MPa以内,比油冷和盐浴冷却的试件降低50%以上。GH4096合金环件固溶处理冷却方式采用风冷与传统的油冷和盐浴冷却方法相比,可以明显降低锻件内部残余应力,蠕变和高温拉伸等性能只有小幅降低,有助于改善GH4096合金薄壁零件冷加工过程的变形问题,提高尺寸控制精度。

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

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 tertiaryγ′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 secondaryγ'phase is slightly increased,the size of the thirdγ'phase is equivalent of wind cooled sample,and the creep and high-temperature tensile properties are slightly reduced.The size of the secondary and tertiaryγ'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.