Mandal Niladri, Hloch Sergej, Das Alok Kumar
Department of Mechanical Engineering, Indian Institute of Technology (ISM), Dhanbad 826004, India.
Faculty of Manufacturing Technologies, Technical University of Kosice with a Seat in Prešov, Štúrova 31, 08001 Prešov, Slovakia.
Materials (Basel). 2022 Jun 21;15(13):4378. doi: 10.3390/ma15134378.
Maraging steel is one of the exotic materials showing the potential for application in the field of the aerospace industry. However, machining these materials with high surface quality and material removal rate is problematic. The micro-electro chemical discharge (MECDM) process is capable of resolving this problem to some extent, however, due to the spark action, it fails to attain a high surface finish. In the current investigation, micro-hole drilling is performed on maraging steel with powder-mixed alumina (1% wt. of AlO) using the micro-electro chemical discharge machining (PMECDM) process. The effect of different input process factors, for example, voltage (V), duty cycle (D), the electrolyte concentration (C), are considered for investigating the machining performance, i.e., rate of material removal (MRR) and roughness of surface (SR) of the machined substrate. Further, a comparative analysis is established between micro-ECDM (MECDM) and mixed powder ECDM (PMECDM). The Box-Behnken design is used to conduct all the experiments and analysis of variance (ANOVA) is used to optimize the results. The outcomes reveal that MRR in PMECDM is enhanced by 34%, and the average surface roughness is reduced by 21% over the MECDM process. The maximum MRR was observed to be 2.44 mg/min and the hole machined by the PMECDM results in a cleaner hole wall surface than the MECDM process due to the grinding action by the powder particles. The residual stress measurement indicates that the PMECDM (-128.3 ± 3.85 MPa) has the lowest equivalent stress as compared to the parent material (-341.04 ± 10.24 MPa) and MECDM (-200.7 ± 6.02 MPa) surfaces. The applied voltage is the most significant parameter, followed by the duty factor and electrolyte concentration for enhancing the MRR and surface finish. The addition of powder improves the surface integrity of the machined surface as compared to the surfaces produced by the MECDM processes.
马氏体时效钢是一种具有在航空航天工业领域应用潜力的特殊材料。然而，以高表面质量和材料去除率加工这些材料存在问题。微电化学放电（MECDM）工艺能够在一定程度上解决这个问题，但是，由于火花作用，它无法获得高表面光洁度。在当前的研究中，使用微电化学放电加工（PMECDM）工艺，对添加了粉末状氧化铝（AlO重量百分比为1%）的马氏体时效钢进行微孔钻削。考虑了不同的输入工艺因素，例如电压（V）、占空比（D）、电解液浓度（C）的影响，以研究加工性能，即加工后基体材料的材料去除率（MRR）和表面粗糙度（SR）。此外，对微电化学放电加工（MECDM）和混合粉末电化学放电加工（PMECDM）进行了对比分析。采用Box-Behnken设计进行所有实验，并使用方差分析（ANOVA）对结果进行优化。结果表明，与MECDM工艺相比，PMECDM中的MRR提高了34%，平均表面粗糙度降低了21%。观察到最大MRR为2.44毫克/分钟，并且由于粉末颗粒的磨削作用，PMECDM加工的孔的孔壁表面比MECDM工艺更清洁。残余应力测量表明，与母材（-341.04±10.24兆帕）和MECDM（-200.7±6.02兆帕）表面相比，PMECDM（-128.3±3.85兆帕）具有最低的等效应力。对于提高MRR和表面光洁度，施加电压是最显著的参数，其次是占空比和电解液浓度。与MECDM工艺产生的表面相比，添加粉末改善了加工表面的表面完整性。
