DETERMINATION OF RESIDUAL STRESSES IN U7A INSTRUMENTAL STEEL AFTER ELECTROEROUSIVE WIRE CUTTING

Authors

DOI:

https://doi.org/10.24025/2306-4412.4.2019.188336

Keywords:

wire electrical discharge machining, electrochemical dimensional processing, residual stress, heat affected zone, single spark discharge.

Abstract

The article deals with residual stresses in thin plate of U7A steel, the working surface of which in different technological cases has been formed by different technologies, namely: main cut by wire electrical discharge machining (WEDM), additional passages with different energy of single spark discharge, sequential layer-by-layer removal of heat affected zone (HAZ) material using highprecision controlled electrochemical modes. Residual stresses were first determined by mechanical measuring of residual plate deformations directly in the machine's working bath (without removing the obtained samples) and calculating the stresses by a known equation which describes the relationship between the sample curvature and the residual stress for a one-dimensional stressed case. The obtained database after the calculations of residual stresses in U7A steel after WEDM correlates well with the results of work of leading researchers in the field of erosion technologies and processes of interaction of electric discharge plasma with metals. The results make it possible to determine the residual stress levels in the HAZ of U7A steel after WEDM and to determine their dependence on the energy of a single spark discharge. For the specific technological case, it is found that the maximum residual stresses relax over time and decrease with decreasing the thickness of the HAZ. It is possible to completely eliminate residual stresses only with the complete removal of the HAZ by non-thermal electrochemical technology, since WEDM modes, even with minimum discharge energies, form the HAZ and corresponding residual stresses. The results obtained can be used in the design of highprecision modes of electrical discharge and combined sequential WEDM and electrochemical machining with the same wire electrode. Besides, additional confirmation of the capabilities of the latest combined sequential WEDM and electrochemical technology not only to form the microgeometry of the surfaces, but also to obtain in the surface layers the required level of residual stresses or to completely eliminate them is obtained.

Author Biographies

Василь Іванович Осипенко, Cherkasy State Technological University

зав. кафедри кафедри проектування харчових виробництв та верстатів нового покоління, професор, Черкаського Державного Технологічного Університету

Андрій Вадимович Кондаков, Cherkasy State Technological University

аспірант кафедри ПХВ та ВНП, Черкаський Державний Технологічний Університет

Олексій Володимирович Тімченко, Cherkasy State Technological University

асистент кафедри ПХВ та ВНП, Черкаський Державний Технологічний Університет

References

N. K. Foteev, Electrical discharge technology. Мoscow: Mashinostroenie, 1980 [in Russian].

E. Macherauch, "Introduction to residual stress", in Advances in surface treatments: 4. Residual stresses, Pergamon Oxford, 1987, pp. 1-35.

E. Macherauch, and K. H. Kloos, "Origin, measurement and evaluation of residual stresses. Residual stresses in science and technology", in Int. Conf. on Residual Stresses, 1986, Garmisch-Partenkirchen, E. Macherauch and V. Hauk, Eds. Germany, 1987, pp. 3-26.

J. Liu, L. Li, and Y. Guo, "Surface integrity evolution from main cut mode to finish trim cut mode in W-EDM of shape memory alloy", Applied Surface Science, 308, pp. 253-260, 2014.

A. Klink, Y. B. Guo, and F. Klocke, "Surface integrity evolution of powder metallur-gical tool steel by main cut and finishing trim cuts in wire-edm", Procedia Engineering, 19, pp. 178-183, 2011.

M. Antar, S. Soo, D. Aspinwall, M. Cuttell, R. Perez, and A. Winn, "WEDM of aerospace alloys using 'CleanCut' generator technology", ISEM XVI, Shanghai, pp. 285-290, 2010.

M. T. Antar et al., "Fatigue response of Udimet 720 following minimum damage WEDM", Materials & Design, 42, pp. 295-300, 2012.

J. F. Liu, and Y. B. Guo, "Residual stress modeling in electric discharge machining (EDM) by incorporating massive random discharges", in 3rd CIRP Conf. Surface In-tegrity (CIRP CSI). Procedia CIRP, 45, pp. 299-302, 2016.

A. V. Bilan, V. I. Osypenko, D. О. Stupak, and J. D. Korol, "Features of the formation of microgeometry and physical properties of the surface layers of steel during electrical discharge machining and sequential electric-al discharge and electrochemical processing with a wire electrode", Uralskii nauchnii vestnik, no. 12 (48), pp. 27-34, 2012 [in Russian].

A. V. Bilan, V. I. Osypenko, and O. P. Plakhotnyi, "Study of the processes of material removal during electrochemical dimensional processing with a wire electrode", Visnyk SevNTU. Ser. Mashyno-pryladobuduvannya ta transport: col. of sci. works (Sevastopol), vol. 118, pp. 107-112, 2011 [in Russian].

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Published

2020-01-13

How to Cite

Осипенко, В. І., Кондаков, А. В., & Тімченко, О. В. (2020). DETERMINATION OF RESIDUAL STRESSES IN U7A INSTRUMENTAL STEEL AFTER ELECTROEROUSIVE WIRE CUTTING. Bulletin of Cherkasy State Technological University, (4), 126–131. https://doi.org/10.24025/2306-4412.4.2019.188336

Issue

No. 4 (2019)

Section

Materials Science, Technology and Equipment of Modern Machine-building and Food Production

URN

http://vtn.chdtu.edu.uaurn:2306:44554.2019.188336

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