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针对航空发动机涡轮盘表面裂纹缺陷,提出一种地磁场环境下的微磁无损检测(NDT)方法。磁化试验测得了广泛使用的镍基高温合金GH4169材料的磁化特性曲线,通过磁性分析,证明该材料的相对磁导率略大于空气的相对磁导率,为弱顺磁性物质。理论分析了微磁检测适用于涡轮盘试件的检测原理和缺陷处的磁异常特征,通过对预置人工槽缺陷的涡轮盘试块进行检测,验证了理论分析的正确性。检测结果表明,随着涡轮盘表面裂纹宽度和深度的增加,磁异常的宽度和峰值也相应增加,裂纹宽度相同时,深度越深,或者说深宽比越大,磁异常越明显,且裂纹产生的位置对定位精度存在一定的影响。该微磁检测方法为涡轮盘表面裂纹缺陷的有效检测提供了新的思路,能进一步推广应用于飞机发动机的其他部件,如转子叶片、涡轮轴等,以及飞机机身上具有相似磁学特性的材料的无损检测。
Aiming at the surface crack defects of aeroengine turbine disk, a micro-magnetic non-destructive testing (NDT) method under the condition of geomagnetic field is proposed. Magnetization test measured the magnetization curve of the widely used nickel-based superalloy GH4169. Magnetic analysis shows that the relative permeability of the material is slightly larger than the relative permeability of air, which is weakly paramagnetic. The theory of micro-magnetic detection is applied to the detection principle and the magnetic anomaly characteristic of the turbine disk specimen. The correctness of the theoretical analysis is verified by testing the turbine disk test block with preset artificial groove defects. The test results show that the width and peak of magnetic anomaly increase with the increase of the width and depth of the crack on the turbine disk surface. When the crack width is the same, the depth is deeper, or the larger the aspect ratio, the more obvious the magnetic anomaly is, and the crack The location of the positioning accuracy has a certain impact. The micro-magnetic detection method provides a new idea for the effective detection of surface flaw defects in turbine disks and can be further popularized for other components of aircraft engines such as rotor blades, turbine shafts and the like, and has similar magnetic characteristics on aircraft fuselages Non-destructive testing of materials.