Method for connecting 2XXX and 7XXX heterogeneous aluminum alloy by laser filler wire

Abstract

The invention discloses a method for connecting 2XXX and 7XXX heterogeneous aluminum alloy by the laser filler wire, which is suitable for the connection field of 2XXX and 7XXX-series of heterogeneous aluminum alloy. The method comprises the following steps of: firstly, assembling two aluminum alloy plates to be welded into a butt joint mode; regulating position relationship among a laser focal point, the wire falling point of an aluminum alloy welding wire and a butt joint gap between two aluminum alloy plates to ensure that the laser beam, the welding wire and the welded aluminum alloy plates are positioned on the reasonable opposite positions; and adopting reasonable welding parameters, laser power, welding speed, wire conveying speed and the like, utilizing AlCu or Alsi welding wires as filler material in the welding process to regulate the ingredient of the welding line and improve the performance of the joint. According to the method, the problems that the 2XXX and 7XXX heterogeneous aluminum alloy is difficult to connect, the welding line is softened during melting, and heat checking tendency exists can be solved.

Description

Technical field: [0001] The invention relates to a laser welding method for connecting 2XXX and 7XXX series dissimilar aluminum alloys through a filler wire, and is suitable for the connection field of 2XXX and 7XXX series dissimilar aluminum alloys. technical background: [0002] On the one hand, the manufacture of transportation vehicles must consider the requirements for performance, and on the other hand, the requirements for economy in the process of manufacturing and use must be considered. In order to achieve the above purpose, it is necessary to continuously reduce the weight of the vehicle under the condition of ensuring the performance of the vehicle. 2XXX and 7XXX aluminum alloys are two heat-treatable high-strength aluminum alloys, which are widely used in the aerospace field due to their low density and high specific strength. They are also substitute materials for modern high-speed trains, light vehicles and cars. Due to the wide application of the two aluminu...

AI Technical Summary

Problems solved by technology

Traditionally, the connection method of aviation aluminum alloy is mainly riveting, which increases the weight of the structure

2XXX and 7XXX series of dissimilar aluminum alloys are mainly connected by bonding, but the bonding strength is low

[0005] In the laser deep penetration welding process, the laser power density exceeds the deep melting threshold of the material to produce deep penetration small holes, which will help the material absorb the laser. However, the small holes do not always exist stably. Stabilization phenomenon leading to instability of the welding process, resulting in deterioration of weld formation

When laser welding aluminum alloy, due to the high evaporation pressure of Al, the laser welding process of aluminum alloy is generally unstable.

Moreover, due to the large difference in the solubility of hydrogen in liquid aluminum alloys and solid aluminum alloys, hydrogen pores are easily formed in aluminum alloy welds.

Unstable welding process and porosity are common problems in aluminum alloy welding

In addition to the characteristics of aluminum alloy welding, laser welding of 2XXX series alloys also needs to solve the problems of thermal cracks and weld softening; while 7XXX series aluminum alloys contain evaporative elements such as Mg and Zn with low boiling points in the alloys, laser welding will Lead to instability of small holes, softening of welds, and deterioration of welding quality

Therefore, the connection of 2XXX and 7XXX series dissimilar aluminum alloys is very difficult

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