Aluminium Tailored Blank Welding With and Without Wire Feed, Using High Power Continuous Wave Nd:YAG Laser 982395
The automotive industry is continually striving to improve product performance and fuel efficiency by reducing the weight of the vehicle. The development of tailored blanks, where flat sheets are butt welded together and then formed into components has proved to be extremely beneficial in these industrial sectors by weight saving and reduction cost.
Laser beam welding, a well established technique for steel is also of special interest for aluminium alloys because the competing resistance welding technique has shown particular difficulties with these materials. However, aluminium alloys have been notoriously difficult to join using lasers due to problems related to their high surface reflectivity, high thermal conductivity, and for some alloys, low boiling point constituents. These, and other material related issues, have led to weld and heat-affected zone (HAZ) cracking, porosity, and degradation in mechanical properties and inconsistent welding performance. Understanding and controlling such problems have been uppermost in the recent research on butt welding within the automotive industry.
The objective of this present work was to evaluate laser welding of 5000 and 6000 series alloys using a continuous wave Nd:YAG laser fitted with a 600mm fibre capable of delivering over 3.50kW average power at the work-piece. Process parameters (i.e. welding speed, joint gaps, wire feed rate etc) were developed. Metallurgical analysis, tensile testing and press forming were carried out to ascertain the weld quality.