Failure analysis of a motor vehicle suspension helical spring

2020;
: 72-82
https://doi.org/10.23939/ujmems2020.01.072
Received: May 07, 2020
Revised: July 25, 2020
Accepted: July 31, 2020

L. Bohun, E. Pleshakov, S. Shvachko, "Failure analysis of a motor vehicle suspension helical spring", Ukrainian Journal of Mechanical Engineering and Materials Science, vol. 6, no. 1, pp. 72-82, 2020.

1
Lviv Polytechnic National University
2
Lviv Polytechnic National University
3
Lviv Polytechnic National University

The purpose of this work is to reveal the cause of the failure of the motor vehicle rear suspension barrel-shaped spring with the progressive elasticity characteristic and predict measures to increase the lifetime of springs of this type. The fracture of the spring occurred on the middle coil, which operates under conditions of more severe stress in comparison with other coils. The chemical composition of the spring material, determined by X-ray fluorescence spectral and microstructural analyzes, corresponded to chromium-silicon steel 54SiCr6. In terms of structure and mechanical properties, the spring material met the standards. No traces of decarburization were detected, and no crack initiation, caused by non-metallic inclusions, was found in the material of the fractured spring. Macroscopic examination of the spring surface did not reveal any cracks, scratches, dents, traces of blows with stones and marks of spring coiling tool. Instead, extensive areas of exfoliation of the protective coating were found. The metallographic analysis revealed selective corrosion in the form of pitting damage in places of exfoliation of the protective coating. The fatigue crack propagates from the certain deep pit with the reorientation of the crack plane along the spiral surface to the central axis of the coil wire. After depletion of the safety margin, the spring broke down quickly. The fast fracture zone contains steps of the river pattern formed due to the spiral reorientation of the fracture surface. The research can be used to understand the importance of adhesive strength and wear resistance of protective coatings on the spring surface. Their local exfoliation causes subsequent corrosion damage to the spring, which stimulates its fatigue fracture.

[1] O.A. Fenenko, “Defekty prujin podveski transportnogo sredstva i protsessy, privodyaschie k nim” [“Defects in vehicle suspension springs and processes leading to them”], Visnyk Kharkivsʹkoho natsionalʹnoho tekhnichnoho universytetu silʹsʹkoho hospodarstva imeni Petra Vasylenka [Bulletin of the Petro Vasylenko Kharkiv National Technical University of Agriculture], vol. 167, pp. 92–99, 2016. [in Russian].

[2] O.A. Fenenko, and M.A. Oksentyuk, “Vliyanie vneshnih faktorov na prosadku prujin podveski transportnogo sredstva” [“The influence of external factors on the subsidence of the vehicle suspension springs”], Zbirnyk naukovykh prats Kharkivskoho natsionalnoho universytetu povitrianykh syl [Collected scientific works of Kharkiv National Air Force University], vol. 52, issue 3, pp. 118–120, 2017. [in Russian].

[3] Y. Prawoto, et al., “Design and failure modes of automotive suspension springs”, Engineering Failure Analysis, vol. 15, pp. 1155–1174, 2008. https://doi.org/10.1016/j.engfailanal.2007.11.003

[4] Y. Chaubey, C. Kumar, and S. Chauban., “Failure analysis of suspension coil spring for passenger car through SEM microstructure investigation”, International Journal of Innovations in Engineering and Technology, vol. 7, issue 1, pp. 82–87, June 2016.

[5] M.A. Yar, et al., “Corrosion behaviour of an industrial shot-peened and coated automotive spring steel AISI 9254”, Сorrosion Engineering, Science and Technology, vol. 53, no. 8, рр. 564–573, 2018. https://doi.org/10.1080/1478422X.2018.1511328

[6] M.F. Berejnitskaya, “Vliyanie ostatochnyh napryajeniy na soprotivlyaemost stali korrozionno-mehanicheskomu razrusheniyu” [“The influence of residual stresses on the resistance of steel to corrosion-mechanical fracture”], Fiziko-Khimicheskaya Mekhanika Materialov [Physicochemical Mechanics of Materials], vol. 23, no. 1, pp. 22–26, Feb. 1987. [in Russian]. https://doi.org/10.1007/BF00718271

[7] Y. Harada, et al., “Effect of microshot peening on fatigue life of spring steel SUP9”, Procedia Engineering, vol. 81, pp. 1493–1498, 2014. https://doi.org/10.1016/j.proeng.2014.10.179

[8] Y. Mahajan, A. Y. Vyavahare, and D. R. Peshwe, “Failure analysis of tension spring”, International Journal of Engineering Research and Technology, vol. 3, issue 5, pp. 953–956, 2014.

[9] M.T. Todinow, “Internal reports on the project high-strength steels for automotive suspension spring”, School of Metallurgy and Materials, The University of Birmingham, Birmingham, United Kingdom, Nov. 1994.

[10] Y. Zhu, Y. Wang, and Y. Huang, “Failure analysis of a helical compression spring for a heavy vehicle’s suspension system”, Case Studies in Engineering Failure Analysis, vol. 2, pp. 169–173, 2014. https://doi.org/10.1016/j.csefa.2014.08.001

[11] G. Vukelic, and M. Brcic, “Failure analysis of a motor vehicle coil spring”, Procedia Structural Integrity, vol. 2, pp. 2944–2950, 2016. https://doi.org/10.1016/j.prostr.2016.06.368

[12] L. Kosec, et al., “Failure analysis of a motor-car coil spring”, Case Studies in Engineering Failure Analysis, vol. 4, pp. 100–103, 2015. https://doi.org/10.1016/j.csefa.2013.12.004

[13] R. Fragoudakis, et al., “The effect of heat and surface treatment on the fatigue behaviour of 56SiCr7 spring steel”, Procedia Engineering, vol. 74, pp. 309–312, 2014. https://doi.org/10.1016/j.proeng.2014.06.268

[14] Pruzhyny. Terminy ta vyznachennia [Springs. Terms and definitions], DSTU 2262-93, 1994. [in Ukrainian].

[15] Prokat iz resorno-pruzhynnoi vuhletsevoi ta lehovanoi stali. Tekhnichni umovy [Rolled spring-loaded carbon and alloyed steels. Specifications], DSTU 8429:2015, 2016. [in Ukrainian].

[16] Stal. Vyznachennia vmistu nemetalevykh vkliuchen. Metalohrafichnyi metod otsiniuvannia za standartnymy shkalamy (ISO 4967:2013, IDT) [Steel. Determination of the content of non-metallic inclusions. Metallographic method of evaluation on standard scales (ISO 4967:2013, IDT)], DSTU ISO 4967:2017, 2017. [in Ukrainian].

[17] Stal. Vyznachannia hlybyny znevuhletsiuvannia (ISO 3887:2003, IDT) [Steel. Determining the depth of decarburization (ISO 3887:2003, IDT)], DSTU ISO 3887:2009, 2016. [in Ukrainian].

[18] Tekhnichna dokumentatsiia na produktsiiu. Pruzhyny. Chastyna 2. Podannia danykh dlia tsylindrychnykh spiralnykh pruzhyn stysnennia [Technical documentation for products. Springs. Part 2. Data representation for cylindrical helical compression springs], DSTU EN ISO 2162-2:2018 (EN ISO 2162-2:1996, IDT; ISO 2162-2:1993, IDT), 2019. [in Ukrainian].

[19] Materialy metalevi. Vyznachennia tverdosti za Vikkersom. Chastyna 1. Metod vyprobuvannia [Metallic materials. Determination of Vickers hardness. Part 1. Test method], DSTU ISO 6507-1:2007, 2010. [In Ukrainian].

[20] H. E. Boyer, and T. L. Gall, Metals Handbook. Materials Park, OH, USA: American Society for Materials Publ., 1985.

[21] Elvatech: Advanced XRF equipment and solutions. [Online]. Available: https://elvatech.com. Accessed on: July 30, 2020.

[22] Metaly ta splavy. Metody metalohrafichnoho kontroliuvannia. Terminy ta vyznachennia poniat’ [Metals and alloys. Methods of metallographic control. Terms and definitions], DSTU 7175:2010, 2011. [in Ukrainian].

[23] Purdue University Cytometry Laboratories. [Online]. Available: www.cyto.purdue.edu. Accessed on: July 30, 2020.

[24] Hariachekatani stali dlia vidpushchenykh i zahartovanykh pruzhyn - Tekhnichni umovy postavky [Hot-rolled steels for tempered and hardened springs - Delivery specifications], DIN EN 10089:2003, 2003. [in Ukrainian].

[25] H&R Company profile. [Online]. Available: https://www.h-r.com/en/company-profile/. Accessed on: July 30, 2020.

[26] J. Gordine, and I. Codd, “The influence of Si up to 1.5 wt% on the tempering of a spring steel”, Journal of the Iron and Steel Institute, vol. 207, issue 1, pp. 461–467, 1969.

[27] Koroziia metaliv i splaviv. Terminy ta vyznachennia osnovnykh poniat’ [Corrosion of metals and alloys. Terms and definitions of basic concepts], DSTU 3830-98, 1999. [in Ukrainian].

[28] A. Yu. Bajanova, “Sravnitelnyi analiz napryajeno-deformirovannogo sostoyaniya prujin s lineynoy i progressivnoy uprugimi harakteristikami” [“Comparative analysis of the stress-strain state of springs with linear and progressive elastic characteristics”], Visnyk Kyivs’koho natsional’noho universytetu tekhnolohiy ta dyzaynu [Bulletin of the Kyiv National University of Technologies and Design], vol. 80, no. 6, pp. 18–24, 2014. [in Russian].