Temperature control in laser brazing of a steel/aluminium assembly using thermographic measurements

• Published in: NDT & E international : independent nondestructive testing and evaluation Vol. 39; no. 4; pp. 272 - 276
• Main Authors: Mathieu, Alexandre, Matteï, Simone, Deschamps, Alexis, Martin, Bruno, Grevey, Dominique
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-06-2006; Elsevier Science; Elsevier
• Subjects: Cross-disciplinary physics: materials science; rheology; Engineering Sciences; Exact sciences and technology; Laser brazing; Laser welding; Materials; Materials science; Materials testing; Physics; Process control; Thermal modelling; Thermography; Laser brazing; Laser welding; Process control; Thermography; Thermal modelling; Metallic structure; Intermetallic compounds; Nondestructive testing; Brittle material; Aluminium; Brazing; Car body; Temperature measurement; Proceedings; Assembling; Metrology; Modelling; Temperature control; Thermal imaging; Steels; Joints
• ISSN: 0963-8695; 1879-1174
• DOI: 10.1016/j.ndteint.2005.08.005

One way of making car bodies lighter is to introduce some aluminium parts in place of steel. Steel and aluminium can be joined by laser braze welding. As in other types of thermal joining, inter-metallic phases may weaken the joint. In laser braze welding, these appear as a thin layer of brittle compounds at the steel/seam interface. Their formation is related to temperature. It has been shown that, if the layer is less than 10
μm thick, the joint is not compromised [Kreimeyer M., Sepold G. Laser steel joined aluminium-Hybrid structures, Proceedings of ICALEO'02, Jacksonville, USA; 2002]. Not only can temperature gradient be calculated by numerical simulation, but it is also possible to measure the surface temperature by thermography. We show here how thermography may be used to control temperature during laser braze welding.