Treatments of steel sheets for the high pressure die casting of aluminum/steel sheet-metal hybrids with low gap and distortion formation (BeST)

• Applicants: Professorin Dr.-Ing. Kirsten Bobzin; Professor Dr.-Ing. Andreas Bührig-Polaczek; Professor Dr.-Ing. Gerhard Hirt
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing ; Coating and Surface Technology ; Metallurgical, Thermal and Thermomechanical Treatment of Materials
• Term: from 2014 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 245566034

• Final Report Year: 2023

Final Report Abstract

As part of the project, the knowledge gained in the first funding phase on the production of lowgap and low-distortion aluminum-steel sheet-metal hybrids was extended by applying it to a geometrically demanding component and, at the same time, process- and geometry-related influencing variables were quantified, leading to the derivation of an optimum strategy for composite production. When using coated inserts, the highest compound strengths could be achieved with a cold gas sprayed AA7075 coating on sheet steel with a surface roughness of Ra = 14 µm. The additional removal of the oxide layer as well as the use of a flux was able to demonstrate a positive effect on the wetting behavior by the cast aluminum alloy EN AC-43500 and thus strengthened the bond between the materials. Furthermore, the process for structuring the sheet metal inserts was successfully adapted for structuring on both sides. Increasing the edge radii at the roll lands of the structural rolls successfully reduced the occurring notch in the produced channels, but it was found that this disproportionately reduces the undercut width. The investigation of subsequent bending operations was assessed as noncritical. In the high-pressure die casting process, strong correlations between the casting process and the compound strength were demonstrated and also quantified for both coated and structured components. In addition, the complete filling of the undercut channels during the mold filling phase was identified as a decisive parameter for the compound strength, while process steps with an influence on the mechanical properties of the cast alloy could only be assigned a subordinate role.

Publications

• Beschichten und Profilieren von Stahlblechen zur Herstellung druckgegossener Aluminium-Stahl-Hybride, Schriftreihe Oberflächentechnik, 15. Aachener Oberflächentechnik Kolloquium, Band 71, (2021)
  Bobzin, K.; Heinemann, H.; Hebing, J. & Erck, M.
  
• Optimization of the Surface Geometry in Structured Cold Rolling for Interlocking of Formed and Die-Cast Metal Components. Defect and Diffusion Forum, 414(2022, 2, 24), 89-94.
  Ringel, Aron & Lohmar, Johannes
  
• Realisieren von HPDC-Aluminium/Stahl Verbunden durch Beschichten und Strukturprofilieren, 16. Aachener Oberflächentechnik Kolloquium, Schriftreihe Oberflächentechnik, Band 73, (2022)
  Bobzin, K.; Heinemann, H. & Erck, M.
  
• Towards 3D Modelling of Cold Rolled Channel Structures for Interlocking Steel-Al Die Casting, 36. ASK Umformtechnik - Ideen Form geben, 2022-10-26 - 2022-10-27, Aachen, Germany, Seiten: 497-508
  Ringel, Aron; Hirt, Gerhard & Lohmar, Johannes
  
• Influence of High-Pressure Die Casting Process Parameters on the Compound Strength of Hybrid Components with Undercut Sheet Metal. Metals, 13(10), 1717.
  Bruckmeier, Lukas; Ringel, Aron; Vroomen, Uwe; Bailly, David & Bührig-Polaczek, Andreas
  
• TS-Beschichtungen als Lösung zum Fügen von Stahl/Al-Verbundgussbauteilen, Thermal Spray Bulletin 02/2023 (2023), ISSN 1866-6248
  Bobzin, K.; Heinemann, H.; Erck, M. & Körner, J.