The material welded is 22MnB5, a press hardenable boron steel, Table 1, with and without coating of AlSi, the material is called Usibor with the coating. After the ...
COMPARISON OF 22MNB5-STEEL WITH AND WITHOUT ALSI-COATING DURING LASER HYBRID ARC WELDING P. Norman1*, G. Wiklund1, P. Janiak2, N. Malmberg2, A. F. H. Kaplan1 1 2
Luleå University of Technology, TVM Department, Luleå, Sweden Swerea KIMAB AB, Stockholm, Sweden
Abstract 22MnB5/Usibor1500 is a hot-dip aluminized manganese-boron steel grade that is used within the car manufacturing industry and as lasers are increasingly used for welding of the car body the amount of research concerning laser welding of this material follows. For thicker material the laser hybrid arc welding process has grown to a well-known tool to increase productivity, but for thinner materials the advantages are less obvious. In the present research the melt pool and wire drop transfer was observed with a high speed camera. Differences between welding, with and without the coating were clearly visible and are described and discussed in the paper. The resulting welds were examined microscopically and chemically to unveil the composition of the material. It is aimed to avoid possible brittle inter-metallic phases directly during the process, hence by skipping the usual additional manufacturing step of removing the AlSicoating in advance. Keywords: laser, hybrid, arc, welding, coating, AlSi, steel
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Introduction
Lightweight structures, good forming properties and, last but not least, high performance in terms of crash behavior whenever the key focus is on safety, are vital aspects in the production of high-grade components for the car body shell. If these properties can be combined with a scale-resistant coating which will prevent oxidization of the surface in the tooling units, and therefore avoiding soiling of the tools, this can be achieved by using a manganese-boron steel alloy with a 25µm thick aluminium-silicon coating. This material, Table 1, is not only used for supporting components in motor vehicles, but also as vital safety components such as lateral impact protection, door sills, and the A and B pillars. Table 1: Chemical composition of 22MnB5[1], average value is shown [ %] 22MnB5
C 0,225
Si 0,25
Mn 1,25
Cr 0,155
P
