Laser welding of fully austenitic twinning induced plasticity (twip) steels

Abstract

One of the key disciplines in today’s automotive engineering is the ever-increasing need to design lighter cars in combination with an increased crash performance. With this end in view, the use of conventional steel grades often leads to a compromise between weight and safety. In other words, designing with conventional steel grades has almost reached its limit.Fortunately, a recently introduced class of so called “twinning induced plasticity” (TWIP) steels offers promising mechanical properties, namely high tensile strength as well as high ductility. These steels can be used for complex sheet metal geometries, and they have advanced crash performance and are low weight at the same time.Nevertheless, studies have revealed limited weldability of TWIP steels, with regard to quality requirements. This is especially true for spot and inert gas welding techniques: the material characteristics can lead to hot cracking in the seams, and distortion of the workpiece [1, 2].As only little data on laser beam welding of novel TWIP steels is available, it is the task of the present study to give an overview of the laser weldability of TWIP steels.One of the key disciplines in today’s automotive engineering is the ever-increasing need to design lighter cars in combination with an increased crash performance. With this end in view, the use of conventional steel grades often leads to a compromise between weight and safety. In other words, designing with conventional steel grades has almost reached its limit.Fortunately, a recently introduced class of so called “twinning induced plasticity” (TWIP) steels offers promising mechanical properties, namely high tensile strength as well as high ductility. These steels can be used for complex sheet metal geometries, and they have advanced crash performance and are low weight at the same time.Nevertheless, studies have revealed limited weldability of TWIP steels, with regard to quality requirements. This is especially true for spot and inert gas welding techniques: the material characteristics can lead to hot cracking in the seams, and distortion of the workpiece [1, 2].As only little data on laser beam weldin...