Flux-cored wire for different-material bonding and method of bonding different materials

Abstract

The present invention provides a flux cored wire which increases bonding strength and is excellent in bonding efficiency in jointing an aluminum-base material with a steel-base material, a method for jointing dissimilar materials and a bonded joint obtained by the method. Specially, the present invention provides the method for jointing dissimilar materials when high-tension steel section and 6000 series aluminum alloy with different strength are executed with welded connection or when steel section is coated with aluminum. In one mode, the flux cored wire which is filled with welding flux in the outer skin of the aluminum product, therefore, the flux is prepared to a fluoride composition containing a certain amount of AlF3 and containing no chloride. The outer aluminum contains 1-13wt% of Si. When the flux cored wire according to the invention is used, a high jointing strength is obtained when high-tension steel section and 6000 series aluminum alloy with different strength are executed with melting welding.

Description

technical field [0001] The present invention relates to a flux-cored wire (FCW: Flux cored wire) for joining dissimilar metal members of iron-based materials and aluminum-based materials and a method for joining dissimilar materials. The technology of the present invention is suitable for structural components such as machine parts and building structures in the field of transportation such as automobiles and railway vehicles, and is particularly required in the assembly process of automobile structures and the like. Background technique [0002] Welding generally joins metal members of the same kind to each other. However, if it can be applied to the joining of different types of metal members (joint bodies of different materials) such as iron-based materials (hereinafter referred to as steel materials) and aluminum-based materials (collectively referred to as pure aluminum and aluminum alloys, hereinafter referred to as aluminum materials), then As a structural material f...

AI Technical Summary

Problems solved by technology

In addition, since joining takes a long time, it cannot be applied to large members such as automobile bodies that require high productivity.

[0042] The MIG welding method using a silicon-added aluminum alloy solid metal wire as the welding wire has the following problems: not only does it require an expensive control power supply for high-precision control of the heat intake condition, but it also has a problem with the shape of the joint. Big limited

However, Patent Document 13 or Patent Document 14 has a problem that when arc welding is actually performed, a large amount of the fluoride-based mixed flux itself coated on the welded portion scatters even under normal conditions, making the welding work itself difficult.

In addition, there is also a problem that the wettability of the weld metal due to the flux is too good and spreads, resulting in incomplete formation of the weld bead, etc.

Therefore, there are problems in that a large amount of flux evaporates during welding, and fumes or splashes occur, which deteriorates workability, and the weld metal composed of aluminum diffuses too much, so that a complete weld bead cannot be formed, and high joint strength cannot be obtained.

In other words, it is true that there has been no proposal on the composition of the flux for the fusion welding of high-strength steel materials and 6000-series aluminum alloy materials that are different in high strength.

Images