Working Group A | Metallurgical joint


Investigation and enhancement on bonding by cold bulk metal forming processes

Prof. Dr.-Ing. Dipl.-Wirtsch.-Ing. Peter Groche, TU Darmstadt
Dr. Andreas Erbe, MPIE Düsseldorf



Cold bulk metal processes provide high dimensional accuracy and good material utilization. The manufactured components are featuring a high surface quality, a low machining allowance, while requiring only low energy consumption for the forming. Because of the cold hardening at low forming temperatures and high strains, cold bulk metal formed components are favorable for high mechanical loads.

Figure 1: Method selection
Figure 1: Method selection

The high tribological loads occurring during cold bulk metal forming can be used to bond two workpieces, enabling the possibility to combine the advantages of cold bulk metal forming with a functional material compound. The potential of this material compound comes along with the opportunity to combine high strength material with lightweight material for weight reduction. Further, expensive corrosion resistant materials can be used to cover surfaces of cheaper, corrosion-prone materials. This technique can also be used to include magnetic properties in a component locally.

The aim of this research project is to investigate the bonding surfaces and the conversion of the inner and outer boundary layer in interdisciplinary cooperation with the methods of surface analysis to deepen the understanding of the bonding mechanism. In the second priority programme’s phase, the design for potential applications of the cold forge welding technology and further opportunities to increase the bond strength are subject to the institutes’ research work. Methods will be established to strengthen or promote bonding of steels to materials in combinations, which are traditionally seen as non-bondable during cold bulk metal forming. Beside the effect of heavy work hardening of the boundary layers by mechanical processes the effect will be analyzed of tempering the billets and varying the geometrical surface structure on the bond strength. Especially the effect of the billets temperature will be investigated intensely to promote bonding and to generate compressive stress due to shrinkage. Further emphasis is put on a subsequent forming processing of the joined components. Due to an unequal distribution of the surface exposure and contact stress, the resulting bond strength varies in a broad range along the weld interface. Thus, in a second forming step further mechanical stress and surface exposure is induced at primarily not welded regions of the component. The suitability and development of heat treatment strategies are pursued with the aim to increase the bond strength and not to influence the mechanical properties of the base material negatively. The research of the second phase leads to the design criterias’ provision for cold extrusion welding processes with specific regard to the material flow and bond formation.



  3D cold pressure welded components – From the bonding mechanisms to the production of high strength joints C. Gerlitzky, T. H. Tran, S. Zhang, N. J. Peter, C. Kuhn, M. Rohwerder, P. Groche
In: Material Science and Engineering Technology, 2019. (accepted)
  Atomic level bonding mechanism in steel/aluminum joints produced by cold pressure welding N. J. Peter, C. Gerlitzky, A. Altin, S. Wohletz, W. Krieger, T. Tran, C. H. Liebscher, C. Scheu, G. Dehm, P. Groche, A. Erbe
Materialia 2019 (in Revision)
  Which Properties must a Surface have to be suitable for Cold Pressure Welding? H. Tran, C. Gerlitzky, M. Rohwerder, P. Groche
In: Proceedings ESAFORM 2019, Vitoria-Gasteiz, Spanien, 8.-10.05. 2019. (accepted)
  The Influence of Silicon in EN AW 6082 Alloys on the Bond Strength in Cold Pressure Welding C. Gerlitzky, S.M. Arbo, I. Westermann, P. Groche
In: Proceedings ESAFORM 2019, Vitoria-Gasteiz, Spanien, 8.-10.05. 2019. (accepted)
  Hochgeschwindigkeitsfügen bei niedrigen Energien B. Niessen, C. Gerlitzky, P. Groche
In: Blechnet, 1, pp. 54-55, 2019
  Wie belastbar sind durch Fließpressen kaltpressgeschweißte Hybridverbunde? C. Gerlitzky, P. Groche
In: 33. Jahrestreffen der Kaltmassivumformer, Düsseldorf, 2019
  Brushing for high performance cold pressure welded bonds Gerlitzky, C. Volz, S. Groche, P.
In: Key Engineering Materials, 767, 309-315, 2018
  Adaption von Kaltmassivumformprozessen auf Basis einer Temperaturerfassung Groche, P. Volke, P. Gerlitzky, C. Ostrowski, J.
In: Neuere Entwicklungen in der Massivumformung, 15. – 17. Mai 2017, Fellbach
  Erzeugung stoffschlüssiger Verbunde durch Kaltfließpressschweißen Wohletz, S.
Dissertation, Shaker, Aachen, 2017
  Cold Pressure Welding – Bonding Mechanisms and the Effect of Surface Treatment on the Bond Formation -Invited Keynote Talk Wohletz, S.; Groche, P.
In: International Symposium on Plasticity 2016, 03.01.2016–09.01.2016, Kona, HI, USA, 2016
  Metallische Verbunde durch Fließpressen Wohletz, S.; Groche, P.; Altin, A.; GmbH, VDI Wissensforum (ed.)
In: 30. Jahrestreffen der Kaltmassivumformer, Düsseldorf, 2015
  Bond Formation by Cold Extrusion Welding Wohletz, S.
In: Department Seminar of the Max-Planck-Institut für Eisenforschung, 01.07.2015, Düsseldorf, 2015
  Formende Fügeverfahren für artungleiche Verbindungen Wohletz, S.; Groche, P.
In: DGM-Fortbildungsseminar Fügen hybrider Verbindungen, 19.11.2014–20.11.2014, Bremen, 2014
  Material Adherence in Cold Welding by Cold Forging Wohletz, S.; Groche, P.
In: The 20th International Symposium on Plasticity and Its Current Applications. Numerical Engineering Analysis and Testing Inc., Freeport, The Commonwealth of The Bahamas, 2014
  Joining by forming – A review on joint mechanisms, applications and future trends Groche, P.; Wohletz, S.; Brenneis, M.; Pabst, C.; Resch, F.
In: Journal of Materials Processing Technology, 214 (214) pp. 1972–1994, 2014
  Nanoscale understanding of bond formation during cold welding of aluminum and steel Altin, A.; Wohletz, S.; Krieger, W.; Kostka, A.; Groche, P.; Erbe, A.
In: Advanced Materials Research, 966-967 pp. 445–452, 2014
  Effect of the primary heat treatment on the bond formation in coldwelding of aluminum and steel by cold forging Groche, P.; Wohletz, S.; Erbe, A.; Altin, A.:
In: Journal of Materials Processing Technology, 214 pp. 2040–2048, 2014
  Temperature Influence on Bond Formation in Multi-material Joining by Forging Wohletz, S.; Groche, P.
In: Procedia Engineering, 81 pp. 2000–2005, 2014
  Combined Cold Extrusion of Aluminum and Steel – A Production Technique Combining High Strength and Lightweight Material in a Cold State Wohletz, S.; Özel, M.; Groche, P.
In: New Developments in Forging Technology, Stuttgart, 2013

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