Flux-cored wire for welding different materials, method for laser welding of different materials and method for MIG welding of different materials

Abstract

There are provided a flux-cored wire for welding different materials, a method for laser welding of different materials and a method for MIG welding of different materials which can improve tensile shear strength of a welded joint portion and peeling strength of a welded portion interface in welding aluminum or an aluminum alloy material and a steel material. The flux-cored wire has a cylindrical sheath comprising an aluminum alloy which contains Si in an amount of 1.5 to 2.5% by mass and Zr in an amount of 0.05 to 0.25% by mass, with the remainder being aluminum and inevitable impurities, and a flux filling inside this sheath and containing cesium fluoride in an amount of 20 to 60% by mass, and the packing fraction of the flux being 5 to 20% by mass of the total mass of the wire.

Description

technical field [0001] The present invention relates to a different-material welding flux-cored wire used for welding different-material components used in transportation machinery such as automobiles and building materials, a different-material laser welding method using the different-material welding flux-cored wire, and a different-material MIG The welding method, in particular, relates to a flux-cored wire for welding different materials, a laser welding method for different materials, and a MIG welding method for different materials, which are suitable for welding aluminum or aluminum alloy materials and galvanized steel sheets. Background technique [0002] Currently, in transportation machines such as automobiles, steel materials are used as materials for vehicle bodies and the like. Steel materials used as components of transportation machinery, etc., are exposed to rainwater during use, so the surface is galvanized for rust prevention. Therefore, the waterproof eff...

AI Technical Summary

Problems solved by technology

However, there is a problem that when steel and aluminum alloy materials are conventionally joined by welding, highly brittle intermetallic compounds are formed at the joint, and the tensile shear strength and peeling strength of the joint are lower than those of welding members of the same type. Reduced strength

[0012] However, in the region where the Si content of the filler material is high, the tensile shear strength increases after joining, but there is a problem that the peel strength decreases

In addition, although the peeling strength is improved in the region where the amount of Si is low, the peeling of the intermetallic compound layer does not occur, but there is a problem that if the difference in thermal expansion between the aluminum material and the steel material is large (for example, when the thickness of the aluminum material is thicker than that of the steel material) etc.), cracks are generated in the welded part (welded metal part) due to thermal shrinkage of the welded part

[0014] However, the generation of intermetallic compound layers cannot be effectively suppressed and high peel strength cannot be obtained regardless of the high Si content or regardless of the main flux content and filling rate in the flux-cored wire.

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