Effects of Shot Peening Process on Fatigue Strength of 50CrV4 Steel Contaning an Artifical Surface Defect

Öz

It is well known that surface defects have a very significant effect on the fatigue strength of engineering materials. The shot peening process is a mechanical surface treatment to enhance surface properties and fatigue strength. In this study, it is aimed to investigate the effects of surface defects on the fatigue strength of 50CrV4 spring steel and the effect of shot peening process effects. Samples including a semicircular slit sized 0,2 mm or a hole sized 3 mm throughout the sample were shot-peened by S230 steel balls. 3-point bending tests were performed on defected and non-defected samples. It was found that the defects acted as a pre-existent crack and samples with hole and semicircular slit significantly reduced the fatigue strength by 85% and 80% (for 672 MPa), respectively. While shot peening enhanced the fatigue strength of the semi-circular slitted sample by 126%, it had almost no effect on the holed sample. Although shot peening increased the fatigue strength of the semi-circular slotted sample, it could not reach that of the non-defected sample. According to the results, it can be concluded that 3 mm hole and 0,2 mm scratch defects cannot be made harmless by the Shot Peening method.

Anahtar Kelimeler

• Shot peening
• artifical surface defect
• fatigue

Proje Numarası

2018-039

Suni Yüzey Kusuru İçeren 50CrV4 Çeliğinin Yorulma Dayanımı Bilyalı Dövme Prosesinin Etkileri

Öz

Yüzey kusurlarının mühendislik malzemeleri üzerinde çok önemli bir etkisi olduğu iyi bilinmektedir. Bilyalı dövme prosesi yüzey özelliklerini ve yorulma dayanımını iyileştiren mekanik bir yüzey işlemidir. Bu çalışmada 50CrV4 yay çeliğinin yorulma mukavemetine yüzey kusurlarının ve bilyalı dövme prosesinin etkilerinin araştırılması amaçlanmıştır. Numune boyunca yarım daire şeklinde 0,2 mm derinliğinde çizik ve 3 mm çapında delik içeren numuneler S230 çelik bilyalar ile dövülmüştür. Kusur içeren ve içermeyen numunelere 3-nokta eğme yorulma testleri gerçekleştirilmiştir. Kusurlar çatlak gibi davranmış ve delik veya yarım-daire çizik içeren numunelerin yorulma mukavemetini sırasıyla (672 MPa için) %85 ve %80 oranında azaltmıştır. Bilyalı dövme çizik içeren numunenin yorulma mukavemetini %126 arttırırken, delik içeren numune üzerinde hemen hemen hiçbir etkisi olmamıştır. Bilyalı dövme çizik içeren numunenin yorulma mukavemetini arttırmasına rağmen, kusurlu numunenin yorulma mukavemetine ulaşamamıştır. Bu sonuçlara dayanarak, bilyalı dövme yöntemi ile 3 mm delik ve 0,2 mm çizik kusurlarının tamamen zararsız hale getirilemeyeceği sonucuna varılabilir.

Anahtar Kelimeler

• Bilyalı dövme
• suni yüzey kusuru
• yorulma

Destekleyen Kurum

Manisa Celal Bayar Üniversitesi BAP Koordinasyon Birimi

Proje Numarası

2018-039

Teşekkür

Bu çalışma Manisa Celal Bayar Üniversitesi BAP Koordinasyon Birimi tarafından desteklenmiştir (Proje kodu:2018-039). Yazarlar Dönmez Debriyaj (İzmir) firmasına numunelerin hazırlanmasına katkılarında dolayı teşekkür eder.

Kaynakça

1. [1] Li H.Y., Han M.S., Li D.W., Li J., and Xu, D.C., “Effect of cyclic heat treatment on microstructure and mechanical properties of 50CrV4 steel”, J Cent South Unıv, 22(2): 409-415 (2015).
2. [2] Nishimura Y., Yanase K, Ikeda Y, Tanaka Y, Miyamoto N, Miyakawa S, Endo M., “Fatigue strength of spring steel with small scratches”, Fatıgue Fract Eng M, 41:1514–1528 (2018).
3. [3] Lin B., Zabeen S., Tong J., Preuss M., Withers P.J., “Residual stresses due to foreign object damage in laser-shock peened aerofoils: simulation and measurement”, Mech Mater, 82:78–90 (2015).
4. [4] Al Mangour B., Yang J.M., “Integration of heat treatment with shot peening of 17-4 stainless steel fabricated by direct metal laser sintering” JOM, 69:2309–2313 (2017).
5. [5] Tan L., Yao C., Zhang D., Ren J., Zhou Z., Zhang J. “Evolution of surface integrity and fatigue properties after milling, polishing, and shot peening of TC17 alloy blades” Int J Fatigue, 136:105630 (2020).
6. [6] Javidi A., Rieger U., Eichlseder W. “The effect of machining on the surface integrity and fatigue life” Int J Fatigue, 30:2050–2055 (2008).
7. [7] Schönbauer B.M., Mayer H. “Effect of small defects on the fatigue strength of martensitic stainless steels” Int J Fatigue, 127:362–375 (2019).
8. [8] Murakami Y., “Effects of Small Defects and Nonmetallic Inclusions”, Met Fatigue, Elsevier, UK, (2002).

9. [9] Karr U., Schuller R., Fitzka M., Schönbauer B., Tran D., Pennings B., Mayer H., “Influence of inclusion type on the very high cycle fatigue properties of 18Ni maraging steel”. J Mater Sci 52:5954–5967 (2017).
10. [10] Shingai K., “Study on elastic-plastic strain behavior of notched specimen (5. Consideration on fatigue life and cyclic strain behavior of steel under cyclic tensile load)”, Reports, Nagasaki University, Faculty of Engineering (1998).
11. [11] Ishii T. and Takahashi K., “Prediction of fatigue limit of spring steel considering surface defect size and stress ratio”, Metals, 11, 483 (2021).
12. [12] Yanase K., Endo M., “Multiaxial high cycle fatigue threshold with small defects and cracks” Eng Fract Mech, 123:182–196 (2014).
13. [13] Fernández-Pariente, I., Bagherifard, S., Guagliano, M., and Ghelichi, R. “Fatigue behavior of nitrided and shot peened steel with artificial small surface defects”, Eng Fract Mech, 103, 2-9 (2013).
14. [14] Zhang J., Li H., Yang B., Wu B., Zhu S., “Fatigue properties and fatigue strength evaluation of railway axle steel: effect of micro-shot peening and artificial defect” Int J Fatigue, 132:105379 (2020).
15. [15] Yang S., Zeng W., Yang J., “Characterization of shot peening properties and modeling on the fatigue performance of 304 austenitic stainless steel” Int J Fatigue 137:105621. (2020).
16. [16] Webster G.A., Ezeilo A.N., “Residual stress distributions and their influence on fatigue lifetimes” Int J Fatigue 23:375–383 (2001).
17. [17] Yasuda, J., and Takahashi, K., “Improvement of Fatigue Limit by Shot Peening for High-Strength Steel Containing a Crack-Like Surface Defect: Influence of Stress Ratio”, ASME 2012 Pressure Vessels and Piping Conference. Volume 9, Rudy Scavuzzo student paper symposium and competition, Toronto, Ontario, Canada, July 15-19, (2012).
18. [18] Saklakoglu N., Bolouri A. Gencalp Irizalp S., Baris F., Elmas A., “Effects of shot peening and artificial surface defects on fatigue properties of 50CrV4 steel”, Int J Adv Manuf Tech, 112, 2961–2970 (2021).
19. [19] Calitz, J., Kok, S., and Delport, D., “The effect of decarburization on the fatigue life of overhead line hardware”, J S Afr I Min Metall, 121(10), 537-542 (2021).
20. [20] Zhang, K., Chen, Y., Sun, Y., and Xu, Z. “Effect of H2O (g) on decarburization of 55SiCr spring steel during the heating process”, Acta Metall Sin-Engl, 54(10), 1350-1358 (2018).
21. [21] Fargas, G., Roa, J. J., and Mateo, A. “Effect of shot peening on metastable austenitic stainless steels”, Mat Sci Eng A-Struct, 641, 290-296 (2015).
22. [22] Suraratchai M., Limido J., Mabru C., Chieragatti R., “Modelling the influence of machined surface roughness on the fatigue life of aluminum alloy Int J Fatigue, 30(12), 2119-2126 (2008).
23. [23] Li X., Zhang J., Yang B., Zhang J., Wu M., Lu L. “Effect of micro-shot peening, conventional shot peening and their combination on fatigue property of EA4T axle steel”, J Mater Process Tech, 75:116320 (2020).
24. [24] Pereira F.G.L. , Lourenço J.M., Nascimento R.M. , Nicolau Apoena Castro, Fracture Behavior and Fatigue Performance of Inconel 625, Mat Res, 21(4) (2018).
25. [25] Trško L., Fintová S., Nový F., Bokůvka O., Jambor M., Pastorek F., Florková Zuzana and Oravcová M., “Study of relation between shot peening parameters and fatigue fracture surface character of an AW 7075 aluminium alloy”, Metals, 8(2), 111, (2018).