GH4738高温合金异形环件组织与性能研究

Study on microstructure and properties of shaped ring parts for super alloy GH4738

利用有限元方法对GH4738高温合金异形环件成形过程进行数值模拟,并在1060℃预轧+1060℃终轧和1080℃预轧+1080℃终轧两种方案下,对异形环件的显微组织和性能进行表征。结果表明,环件整体的等效应变分布沿轴向梯度变化,但等效应变分布均匀性较低,环件成形难度大。采用1080℃预轧+1080℃终轧的方法,更有利于获得均匀的显微组织,此温度下获得均匀显微组织所需的等效应变不大于0. 5。两种方案下的抗拉强度、塑性和蠕变性能基本一致,1080℃下的室温屈服强度略低,而高温屈服强度较高,持久性能是1060℃下的1. 8倍。因此,在1080℃预轧+1080℃终轧、轧制等效应变不小于0. 5的条件下,对该GH4738高温合金异形环件进行轧制,能够获得均匀的显微组织,并且有助于提高环件的持久性能。

The forming process of shaped ring part for super alloy GH4738 was numerically simulated by the finite element method,and the microstructure and properties of shaped ring part were characterized under two schemes of pre-rolling and final rolling at 1060 ℃ and pre-rolling and final rolling at 1080 ℃,respectively. The results show that the distribution of equivalent strain for the whole ring part varies along the axial gradient,but the uniformity of equivalent strain distribution is lower to make the ring form difficultly. However,the method of pre-rolling and final rolling at 1080 ℃ is more conducive to obtaining uniform microstructure,and the equivalent strain required to obtain uniform microstructure at this temperature is no more than 0. 5. Furthermore,the tensile strength,plasticity and creep properties under two schemes are basically the same,and the yield strength at room temperature under 1080 ℃ is slightly lower,while the yield strength at high temperature is higher,and the stress rupture property is 1. 8 times of that at 1060 ℃ . Therefore,under the condition that the equivalent strain of rolling is no less than 0. 5 and the scheme of pre-rolling and final rolling at 1080 ℃ is adopted,the shaped ring part of super alloy GH4738 is rolled,and the uniform microstructure is obtained to help to improve the stress rupture property of ring parts.