In the high-stakes world of aero-engine manufacturing, even the smallest flaw can have catastrophic consequences. A recent study led by WANG Xuemin, published in the journal ‘Jixie qiangdu’ (Mechanical Strength), has shed light on a critical issue that could significantly impact the energy sector. The research focuses on the failure analysis of low-pressure turbine shaft oil passage holes, a component crucial for the efficient operation of aero-engines.
During high and low circumferential compound fatigue tests, cracks were observed in the oil passage holes of low-pressure turbine shafts. These cracks, though small, posed a significant threat to the structural integrity of the engine. The study delved deep into the nature and causes of these cracks, employing a multidisciplinary approach that included appearance examination, fracture analysis, surface inspection, metallographic organization, finite element analysis, and crack expansion simulation.
The findings were stark. The cracks were identified as fatigue cracks, originating from the incomplete removal of the remelting layer after the passage holes were cut by electrical discharge machining. This remelting layer, a byproduct of the machining process, contained microcracks that acted as initiation sites for larger cracks under the stress of high and low circumferential composite loads. “The presence of these microcracks significantly reduces the fatigue life of the component,” WANG Xuemin explained, highlighting the urgency of addressing this issue.
The study estimated the initial crack length to be between 0.2-0.3 mm, a size that is nearly impossible to detect with conventional inspection methods. This underscores the need for advanced inspection techniques and more robust machining processes. The research suggests designing special tooling and using advanced machining technologies to eliminate the influence of the remelting layer, ensuring the processing quality of the through oil hole.
The implications of this research are far-reaching. In an industry where safety and reliability are paramount, understanding and mitigating the risks associated with these cracks is crucial. For the energy sector, which relies heavily on aero-engines for power generation and transportation, this study provides valuable insights that could lead to more durable and efficient engine designs.
As the demand for energy continues to grow, so does the need for reliable and efficient aero-engines. This research, published in ‘Jixie qiangdu’ (Mechanical Strength), could pave the way for future developments in the field, ensuring that the engines powering our world are not only powerful but also safe and reliable. By addressing the issue of remelting layers and microcracks, manufacturers can enhance the longevity and performance of their products, ultimately benefiting the entire energy sector.
