Elektro Erozyonla Tornalama Yöntemiyle İşlenen Soğuk İş Takım Çeliğinin Yorulma Ömrünün Tahmini

Bu çalışmada, elektro erozyon ile tornalamada (EET) işleme parametrelerinin yüzey bütünlüğü ve işlenmiş parçanın yorulma ömrüne etkilerinin belirlenmesi amaçlanmıştır. İlk olarak, iş parçasının dönmesini sağlamak amacıyla bir mekanizma tasarlanarak imal edilmiştir. EET deneyleri, AISI L2 takım çeliği üzerinde üçer farklı boşalım akımı, vurum süresi ve bekleme süresi ile sabit devir sayısı kullanılarak yapılmıştır. Deneyler, L9 dikey dizisine göre yapılmış olup, işleme performans çıktıları olarak Rz, Sm ve sertlik değerleri ölçülmüştür. Son olarak, √area modeli uygulanarak işlenen parçaların yorulma ömrü tahmin edilmiş ve işleme parametrelerine göre teorik yorulma ömrünün değişimi araştırılmıştır. Deneysel sonuçlara göre, boşalım akımı ve vurum süresinin artmasıyla Rz ve Sm parametrelerinde bir artış belirlenmiştir. En düşük Rz ve Sm değerleri 3 A boşalım akımı, 3µs vurum süresi ve 5 µs bekleme süresinde elde edilmiştir. Taguchi analizine göre optimum teorik yorulma gerilmesi A1Ton1Toff3 deney dizisinde işlenen parça için √area modeli ile 643.932 MPa olarak hesaplanmıştır.

Anahtar Kelimeler:

Elektro erozyon, Tornalama, Yüzey pürüzlülüğü, Yorulma ömrü, Takım çeliği

Estimation of Fatigue Life of Cold Work Tool Steel Machined by Electrical Discharge Turning

In this study, it was aimed to determine the effects of machining parameters on the surface integrity and fatigue life of the machined part in electrical discharge turning (EDT). Initially, a mechanism was designed and manufactured to ensure rotation of the workpiece. EDT experiments were carried out on AISI L2 tool steel using three different discharge currents, pulse on time, pulse off time and constant rotational speed. The experiments were carried out according to the L9 orthogonal array, and Rz, Sm and hardness values were measured as processing performance outputs. Finally, the fatigue life of the machined parts was estimated by applying the √area model and the change of theoretical fatigue life according to the machining parameters was investigated. According to experimental results, an increase in Rz and Sm parameters was determined with increasing the discharge current and pulse on time. The lowest Rz and Sm values were obtained at 3 A discharge current, 3 µs pulse on time and 5 µs pulse off time. Based on Taguchi analysis, the optimum theoretical fatigue stress was calculated as 643.932 MPa with √area model for the machined workpiece in the A1Ton1Toff3 experiment sequence.

Keywords:

Electro erosion, turning, surface roughness, fatigue life, tool steel,

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[1] Davim, J. Paulo, “Surface integrity in machining”. Springer, Vol. London:1848828742, (2010)
[2] Rasti, A., Sadeghi, M. H., & Farshi, S. S. “An investigation into the effect of surface integrity on the fatigue failure of AISI 4340 steel in different drilling strategies”, Engineering Failure Analysis, 95, 66-81, (2019)
[3] Pramanik, A., & Basak, A. K. “Effect of wire electric discharge machining (EDM) parameters on fatigue life of Ti-6Al-4V alloy”, International Journal of Fatigue, 128, 105186, (2019)
[4] Tekaüt, İ., “Theoretical Evaluation of the Effect of Surfaces Processed with Abrasive Water Jet on Fatigue Life”, Transactions of FAMENA, 43(2), 85-98.), (2019)
[5] Jawahir IS, Brinksmeier E, M’Saoubi R, Aspinwall DK, Outeiro JC, Meyer D, et al. “Surface integrity in material removal processes: Recent advances”, CIRP Ann - Manuf Technol, (2011)
[6] Amorim FL, Weingaertner WL, “The behavior of graphite and copper electrodes on the finish die-sinking electrical discharge machining (EDM) of AISI P20 tool steel”, J Brazilian Soc Mech Sci Eng, 29:366–71,(2007)
[7] Ho KH, Newman ST., “State of the art electrical discharge machining (EDM)”, Int J Mach Tools Manuf., (2003)
[8] Erdem, O., Çoğun, C., Urtekin, L., Özerkan, H. B., & Uslan, İ.. Toz katkılı ve ısıtılmış dielektriğin elektro erozyon ile işlemede (EEİ) delik delme performansı üzerine etkisi, “Journal of the Faculty of Engineering and Architecture of Gazi University”, 31(3), 531-544, (2016)
[9] Cogun, C., Esen, Z., Genc, A., Cogun, F., & Akturk, N., “Effect of powder metallurgy Cu-B4C electrodes on workpiece surface characteristics and machining performance of electric discharge machining”, Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 230(12), 2190-2203, (2016)
[10] Gohil V, Puri YM., “Turning by electrical discharge machining: A review”, Proc Inst Mech Eng Part B J Eng Manuf; 231:195–208, (2017)
[11] Gupta K, Gupta MK., “Developments in nonconventional machining for sustainable production: A state-of-the-art review”, Proc Inst Mech Eng Part C J Mech Eng Sci., 233:4213–32, (2019)
[12] Kumar, R., Roy, S., Gunjan, P., Sahoo, A., Sarkar, D. D., & Das, R. K. “Analysis of MRR and surface roughness in machining Ti-6Al-4V ELI titanium alloy using EDM process”, Procedia Manufacturing, 20, 358-364, (2018)
[13] Matoorian, P., Sulaiman, S., & Ahmad, M. M. H. M., “An experimental study for optimization of electrical discharge turning (EDT) process”, Journal of Materials Processing Technology, 204(1-3), 350-356, (2008)
[14] Pant, P., & Bharti, P. S., “Electrical Discharge Machining (EDM) of nickel-based nimonic alloys: A review”, Materials Today: Proceedings. (2019)
[15] Yue, X., Li, Q., & Yang, X., “Influence of thermal stress on material removal of Cf_SiC composite in EDM”, Ceramics International. (2019)
[16] Dwivedi AP, Choudhury SK.,” Effect of Tool Rotation on MRR, TWR, and Surface Integrity of AISI-D3 Steel using the Rotary EDM Process”, Mater Manuf Process, 31:1844–52, (2016)
[17] Gohil, V., & Puri, Y. M., “Statistical analysis of material removal rate and surface roughness in electrical discharge turning of titanium alloy (Ti-6Al-4V)”, Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 232(9), 1603-1614, (2018)
[18] Y.H. Guu, H. Hocheng, N.H. Tai, S.Y. Liu, “Effect of electrical discharge machining on the characteristics of carbon fiber reinforced carbon composites”, J. Mater. Sci. 36 (8) 2037–2043, (2001)
[19] Patowari, P. K., Saha, P., & Mishra, P. K., “Taguchi analysis of surface modification technique using W-Cu powder metallurgy sintered tools in EDM and characterization of the deposited layer”, The International Journal of Advanced Manufacturing Technology, 54(5-8), 593-604, (2011)
[20] Zhang, M., Zhang, Q., Dou, L., Liu, Q., & Dong, C., “Comparisons of single pulse discharge crater geometries in EDM and EAM”, Journal of Manufacturing Processes, 22, 74-81, (2016)
[21] Mazarbhuiya, R. M., Dutta, H., Debnath, K., & Rahang, M. “Surface modification of CFRP composite using reverse-EDM method”, Surfaces and Interfaces, 100457. (2020)
[22] Lundberg, M., Saarimäki, J., Moverare, J. J., & Calmunger, M., “Surface integrity and fatigue behaviour of electric discharged machined and milled austenitic stainless steel”, Materials Characterization, 124, 215-222, (2017)
[23] Schönbauer, B. M., & Mayer, H.,”Effect of small defects on the fatigue strength of martensitic stainless steels”, International Journal of Fatigue, 127, 362-375, (2019)
[24] Åman, M., Okazaki, S., Matsunaga, H., Marquis, G. B., & Remes, H., “Interaction effect of adjacent small defects on the fatigue limit of a medium carbon steel”, Fatigue & Fracture of Engineering Materials & Structures, 40(1), 130-144, (2017)
[25] Nishimura, Y., Yanase, K., Ikeda, Y., Tanaka, Y., Miyamoto, N., Miyakawa, S., & Endo, M., “Fatigue strength of spring steel with small scratches”, Fatigue & Fracture of Engineering Materials & Structures, 41(7), 1514-1528, (2018)
[26] Murakami, Y., “Effect of surface roughness on fatigue strength”, Metal Fatigue: Effect of Small Defects and Non Metallic Inclusions, 28-40. (2002)
[27] Banerjee, A., & Prusty, B. G. “Fatigue and fracture behaviour of austenitic-martensitic high carbon steel under high cycle fatigue: An experimental investigation”, Materials Science and Engineering: A, 749, 79-88. (2019)
[28] Garb, C., Leitner, M., & Grün, F., “Application of√ area-concept to assess fatigue strength of AlSi7Cu0. 5Mg casted components”, Engineering Fracture Mechanics, 185, 61-71, (2017)
[29] Murakami, Y., Masuo, H., Tanaka, Y., & Nakatani, M., “Defect Analysis for Additively Manufactured Materials in Fatigue from the Viewpoint of Quality Control and Statistics of Extremes”, Procedia Structural Integrity, 19, 113-122, (2019)
[30] Zhang, J., & Fatemi, A., “Surface roughness effect on multiaxial fatigue behavior of additive manufactured metals and its modeling”, Theoretical and Applied Fracture Mechanics, 103, 102260, (2019)
[31] Özerkan, H. B., “Theoretical investigation of the effect of surface roughness on the fatigue life of austenitic stainless steels”, Materials Today: Proceedings, 11, 417-422, (2019)
[32] Çoğun, C., Kocabaş, B., & Özgedik, A., “Elektro Erozyon ile İşlemede (EEİ) İşparçasi Yüzey Pürüzlülük Profilinin Deneysel Ve Teorik Olarak İncelenmesi”, Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi, 19(1), (2004)