Inductively supported laser beam welding of high and ultra high strength steel grades

Abstract

Sustainability, weight reduction and reduction of CO2-emissions are the key words when it comes to car body construction. The EU-Project „Sustainable Production Technologies of Emission Reduced Light-Weight Car Concepts“ (SuperLightCar) has been launched to develop a car body which meets these high ecological demands during its whole lifecycle. This aim is to be achieved with the help of new technologies and new materials. As one of overall 36 project partners Laser Zentrum Hannover e.V. (LZH) is in charge of investigating the feasibility of inductively supported laser beam welding on novel TRIP und TWIP steel grades as well as boron alloyed and iron manganese steel grades. This process has been developed in order to reduce the hardness within the weld seam structure – and thus increasing its ductility-using the annealing effect of the inductive heating. After this treatment it is possible to form the semi finished part without a ripping of the weld seam. The heat treatment takes place directly after the welding process which means there is no additional production step required. Depending on material properties and work piece thickness a processing speed of up to 9 m/min is possible, when using a lamp-pumped Nd:YAG-Laser with 4 kW maximum output and a focal diameter of 600 µm. The process is applicable for butt and overlap joints with linear weld seam geometries.Sustainability, weight reduction and reduction of CO2-emissions are the key words when it comes to car body construction. The EU-Project „Sustainable Production Technologies of Emission Reduced Light-Weight Car Concepts“ (SuperLightCar) has been launched to develop a car body which meets these high ecological demands during its whole lifecycle. This aim is to be achieved with the help of new technologies and new materials. As one of overall 36 project partners Laser Zentrum Hannover e.V. (LZH) is in charge of investigating the feasibility of inductively supported laser beam welding on novel TRIP und TWIP steel grades as well as boron alloyed and iron manganese steel grades. This process has been developed in order to reduce the hardness within the weld seam structure – and thus increasing its ductility-using the annealing effect of the inductive heating. After this treatment it is possible to form the semi finished part without a ripping of the weld seam. The heat treatment takes place directly after the ...