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Numerical and experimental investigations on shot-peened high-strength steel by means of hole drilling, X-ray, synchrotron and neutron diffraction analysis

Numerische und experimentelle Untersuchungen an kugelgestrahltem hochfesten Stahl mittels Bohrlochverfahrens, Röntgen-, Synchrotron- und Neutronendiffraktionsanalyse
Majid Farajian, Volker Hardenacke, Wulf Pfeiffer, Manuela Klaus and Joana Rebelo Kornmeier
From the journal Materials Testing

Abstract

Numerous experimental works have been devoted to studying the influence of different shot peening parameters on the surface material conditions in different metals in the last decades. Most of the research work has been focused on experimental determination of the residual stress and its depth profile by means of X-ray diffraction and corresponding electro-polishing of the surface layers or byhole drilling method. This state of knowledge has led to the development of phenomenological models to describe the surface material conditions qualitatively. Since there are quite a number of parameters, which could influence the residual stress field after shot peening, covering the whole possible process parameters combinations with the purpose of experimentally determining the residual stress profiles could be difficult. A deeper insight into the residual stress states after shot peening could be possible on the basis of sound physical principles by means of numerical approaches. In this study, shot peening of high strength steel S690QL has been modeled and simulated. The results have been compared with the residual stress depth profiles determined by X-ray, synchrotron, neutron diffraction and hole drilling method.

Kurzfassung

Zahlreiche experimentelle Arbeiten sind seit Jahrzehnten an verschiedenen Metallen durchgeführt worden mit dem Ziel, den Einfluss von Kugelstrahlen auf die oberflächennahe Werkstoffzustände zu untersuchen. Die meisten der Forschungsarbeiten konzentrieren sich auf die experimentelle Bestimmung der Eigenspannungen und deren Tiefenprofile mit Hilfe von Röntgenbeugung mit entsprechendem Elektropolieren der Oberflächenschichten oder Bohrlochverfahren. Diese wertvolle Wissensbasis hat zur Entwicklung von phänomenologischen Modellen geführt, die die Oberflächenwerkstoffzustände qualitativ beschreiben. Da es eine ganze Reihe von Prozessparametern gibt, die das Eigenspannungsfeld nach dem Kugelstrahlen beeinflussen können, ist die reine experimentelle Eigenspannungsbestimmung schwierig und kostspielig. Ein tiefer Einblick in die Eigenspannungszustände nach dem Kugelstrahlen ist, basierend auf Werkstoffmechanik und numerische Simulation, möglich. In dieser Veröffentlichung wurde das Kugelstrahlen von hochfestem Stahl S690QL modelliert und simuliert. Die Ergebnisse wurden durch Röntgen-, Synchrotron- und Neutronenbeugungsverfahren und auch durch Bohrlochmethode bestimmt und mit den Eigenspannungstiefenprofilen verglichen.


*Correspondence Address, Dr. -Ing. Majid Farajian, Fraunhofer-Institut für Werkstoffmechanik IWM, Wöhlerstr. 11, 79108 Freiburg, Germany, E-mail:

Dr.-Ing. Majid Farajian, born in 1976, received his BSc in Mechanical Engineering from Tehran Polytechnic, Iran, and his MSc in Materials Processing from the Royal Institute of Technology in Stockholm, Sweden. He received his PhD from the Faculty of Mechanical Engineering of the University of Braunschweig, Germany in 2011. After two years post-doctoral research activities, he continued his work in the field of fatigue and residual stresses at the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany. Since then, he is the head of the team “Component Strength” at the Fraunhofer IWM.

Dr. Volker Hardenacke, born in 1980, received his first degree in Engineering Solid Mechanics from University of Siegen, Germany in 2007. Since then, he has been a researcher at the Fraunhofer Institute for Solid Mechanics, Freiburg, Germany, where he received his PhD in 2015.

Dr. Wulf Pfeiffer studied Mechanical Engineering and Materials Science at Technical University of Karlsruhe, Germany. In 1980, he joined the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany. In 1989, he became the head of the group “Surface treatment” which dealt with mechanical treatment, plasma nitriding and plasma enhanced coating techniques. In the following years, he specialized on the influence of machining and wear on the near surface characteristics of high strength ceramics. In 1993, he submitted his doctoral thesis on “Characterization and Assessment of Hard Machined Ceramics Using X-ray Diffraction and Fracture Mechanical Methods”. In 2004, he became Head of the business group “Process and Material Assessment”, in 2010, he became Head of the business group ”Material Assessment, Life Time Concepts”. The group “Microstructure, Residual Stresses”, which he also leads, focusses on environmental degradation of materials.

Dr. Manuela Klaus, born in 1978, received her diploma in Materials Science and her PhD from the Faculty of Materials Science and Technology of the Technical University in Berlin, Germany. Since that time, she is a scientific assistant at Helmholtz Center Berlin, where she is responsible for the synchrotron beamline EDDI for energy dispersive diffraction. Her special research interest is focussed on the depth resolved analysis of residual stresses by X-ray diffraction.

Dr. Joana Rebelo Kornmeier, born in 1969, received her first degree in Engineering Physics from the Physic Department, Coimbra University, Portugal in 1992. Her Master in Technological Physics was concluded in 1995, and her PhD in Technological Physics in 2002, both were received atfUniversity of Coimbra. After two years of post-doctoral research activities at Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), in cooperation with EADS Space Transportation GmbH Ottobrunn, Germany, she is currently working as instrument scientist at the material science diffractometer STRESS-SPEC at FRM II of Technische Universität Munich, Germany.


References

1 W.Wohlfahrt: Residual stress and stress relaxation, Sagamore Army Mat. Res. Conf. Vol. 28, Eds.: KulaE., WeissV., Plenum Press (1982), pp. 7192 Search in Google Scholar

2 W.Wohlfahrt: The influence of peening conditions on the resulting distribution of residual stress, Proceedings of the 2nd International Conference on Shot Peening, Chicago, USA (1984) Search in Google Scholar

3 O.Vöhringer: Changes in the state of the material by shot peening, Proceedings of the 3rd International Conference on Shot Peening, Garmisch-Partenkirchen, Germany (1987) Search in Google Scholar

4 B.Scholtes: Eigenspannungen in mechanisch randschichtverformten Werkstoffzuständen: Ursachen, Ermittlung und Bewertung, DGM Informationsgesellschaft Verlag (1990) Search in Google Scholar

5 V.Schulze: Modern Mechanical Surface Treatment, States, Stability, Effects, Wiley-VCH Verlag GmbH (2006) Search in Google Scholar

6 M.Farajian, T.Nitschke-Pagel, H. P.Lieurade: Shot Peening as a tool for fatigue strength improvement of welds: A review, International Institute of Welding, XIII-WG6 -009-12 (2012) Search in Google Scholar

Published Online: 2017-01-27
Published in Print: 2017-02-03

© 2017, Carl Hanser Verlag, München