TWI Industrial Member Report Summary 797/2004
C M Allen and C H J Gerritsen
Demands for lightweighting in the automotive sector are promoting the replacement of steel body panels by aluminium in applications such as bonnets, boot lids, and doors.
This report evaluates a relatively new laser-based joining process for aluminium to steel joints. A defocused laser impinges on a steel sheet, either abutting or overlapping an aluminium sheet. Ideally the laser heats the steel sheet without melting it, the heat is conducted through the steel and melts the adjacent aluminium sheet. The molten aluminium then wets the steel to form a bond. In the UK this process is called laser joining but is often referred to by a number of other terms, including laser welding, laser brazing or laser welding/brazing.
Laser joining is compared in this report to two other joining processes, self-piercing riveting, and adhesive bonding.
- To establish the feasibility of laser joining aluminium sheet to steel sheet
- To compare the static mechanical properties of laser joined test pieces to the 'benchmarks' of self-piercing riveted, and adhesively bonded joints