J. P. Bergmann, U. P. D. -. I. H. J. Wilden, Technische Universität Ilmenau, Ilmenau, Germany; S. F. Goecke, EWM HIGHTEC WELDING GmbH, Mündersbach, Germany
Zinc coated steels are set in different applications in mechanical engineering, as for example in automotive, household appliances and plant construction. Joining of zinc coated steels is carried out by welding or brazing. The low melting temperature of zinc (420°C) and the low melting point (907°C) represent some difficulties when welding, as the process is affected from spatter formation, due to the abrupt evaporation of zinc. Further more in the region next to the welding seam and also on the sheet back side the coating is destroyed, so that corrosion resistance can be affected negatively. In order to avoid this phenomena brazing of zinc coated steels with CuSi3 or CuAl8 alloys represents nowadays the state of the art. The low melting temperature of the filler materials allows the joining of zinc coated steels with a low damaging of the zinc coating (working temperature 950-1000 °C).
In comparison to copper alloys zinc alloys as ZnAl4 or ZnAl15 allow a lower temperature joining of zinc coated steels. Investigations regarding the process ability of these materials with laser as well as with a new short arc technology are reported in this paper. The high wettability of zinc allows an optimised spread of the solder material, so that the lower mechanical properties of zinc towards CuSi3 can be compensated from the wide bearing area in overlap and edge joints. Further more the new short arc technology can be set for joining steel/aluminium hybrid joints with an optimised mechanical behaviour.
Process aspects as well as mechanical properties will be discussed in the paper. The failure sites will be analysed and correlated to the mechanical properties, so that a characterisation of the set of ZnAl-filler wires for soldering zinc coated steels will be possible. The investigations will be performed on hot-dip as well as electrolytically coated sheets.
Zinc coated steels are set in different applications in mechanical engineering, as for example in automotive, household appliances and plant construction. Joining of zinc coated steels is carried out by welding or brazing. The low melting temperature of zinc (420°C) and the low melting point (907°C) represent some difficulties when welding, as the process is affected from spatter formation, due to the abrupt evaporation of zinc. Further more in the region next to the welding seam and also on the sheet back side the coating is destroyed, so that corrosion resistance can be affected negatively. In order to avoid this phenomena brazing of zinc coated steels with CuSi3 or CuAl8 alloys represents nowadays the state of the art. The low melting temperature of the filler materials allows the joining of zinc coated steels with a low damaging of the zinc coating (working temperature 950-1000 °C).
In comparison to copper alloys zinc alloys as ZnAl4 or ZnAl15 allow a lower temperature joining of zinc coated steels. Investigations regarding the process ability of these materials with laser as well as with a new short arc technology are reported in this paper. The high wettability of zinc allows an optimised spread of the solder material, so that the lower mechanical properties of zinc towards CuSi3 can be compensated from the wide bearing area in overlap and edge joints. Further more the new short arc technology can be set for joining steel/aluminium hybrid joints with an optimised mechanical behaviour.
Process aspects as well as mechanical properties will be discussed in the paper. The failure sites will be analysed and correlated to the mechanical properties, so that a characterisation of the set of ZnAl-filler wires for soldering zinc coated steels will be possible. The investigations will be performed on hot-dip as well as electrolytically coated sheets.
