PSI - Issue 18

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000–000

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ScienceDirect

Procedia Structural Integrity 18 (2019) 274–279

25th International Conference on Fracture and Structural Integrity Barkhausen noise-based fatigue life prediction of deep drilled AISI 4140 Nikolas Baak a *, Jan Nickel b , Dirk Biermann b , Frank Walther a a Department of Materials Test Engineering (WPT), TU Dortmund University, D-44227 Dortmund, Germany b Institute of Machining Technology (ISF), TU Dortmund University, D-44227 Dortmund, Germany 25th International Conference on Fracture and Structural Integrity Barkhausen noise-based fatigue life prediction of deep drilled AISI 4140 Nikolas Baak a *, Jan Nickel b , Dirk Biermann b , Frank Walther a a Departmen of Materials Test Engineering (WPT), TU Dortmu d Un versity, D-44227 Dortmund, Germany b Institute of Machining Technology (ISF), TU Dortmund University, D-44227 Dortmund, Germany

Abstract High-strength steels like AISI 4140 are commonly used for high dynamically loaded parts. Increasing demands for lightweight parts with higher performance and efficiency in automotive industry claim improving material properties. An optimised drilling process should enhance the fatigue life of deep-drilled components by the induction of residual stresses in the borehole, without the need for expensive additional processing steps, e.g. autofrettage. Non-destructive testing techniques like magnetic Barkhausen noise analysis offer quick and reliable possibilities to detect and classify material parameters like hardness and residual stresses. The aim of this study is to evaluate and extrapolate the resulting fatigue performance of deep drilled round specimens due to drilling parameters at an early stage of fatigue life. It was shown, that the coercive field strength decreases approximately linear with proceeding fatigue damage. The slope of the degradation coefficient is comparable for different surface layer conditions. This leads to the assumption that the variation of the micromagnetic parameters is caused by fatigue-induced microstructural changes. Therefore, a microstructure-based prediction of the fatigue life by means of micromagnetic measurements can be established. Abstract High-strength steels like AISI 4140 are commonly used for high d namically loaded parts. Increasing demands for lightweight arts wit high r performance and ef iciency in automotive industry claim improving material properties. An optimised drilling process should e hance the fatigue lif of deep-drilled components by the ind tion of residual stresses in the borehole, without the need for expensive additional processing steps, e.g. autofrettage. Non-destructive testing techniques like magn tic Barkhau n noise analysis offer quick and reli ble possibi iti s to detect and classify material param ters like hardness and residual stresses. The aim of this study is to evaluate and xtrapolate the resulting fatigue p rformance of deep drilled round s ecimens due to d illing arameters at an arly stage of fatigue lif . It was shown, that the coercive field strength decre ses pproximately linear with proceeding fatigue damage. The slope the degradation coefficient is compar bl for different surfa layer c nditions. This leads to th assumption that th v riation of the microma n tic para ter is caused by fatigu -induced microstructural changes. Therefore, a microstructure-based prediction of the fatigue life by means of micromagnetic measurements can be established.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. Keywords: deep drilling; non-destructive testing; Barkhausen-noise; residual stresses; fatigue Keywords: deep drilling; non-destructive testing; Barkhausen-noise; residual stresses; fatigue

1. Introduction Deep drilling is a very common machining process, for the manufacturing of high cyclically loaded engine components, e.g. parts of a common rail system, as rails or injectors (Vormwald et al. 2018). To improve the fatigue 1. Introduction Deep drilling is a very co on machining process, for the manufacturing of high cyclically loaded engine components, e.g. parts of a common rail system, as rails or injectors (Vormwald et al. 2018). To improve the fatigue

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. * Correspon ing auth r. Tel.: +49-231-7558410; fax: +49-231-7558029. E-mail address: nikolas.baak@tu-dortmund.de * Corresponding author. Tel.: +49-231-7558410; fax: +49-231-7558029. E-mail address: nikolas.baak@tu-dortmund.de

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2019.08.164