New original method and device for testing aluminum alloys susceptibility for extrusion welding

Abstract

Common methods of weldability assessment of aluminium alloys do not fully reflect the welding conditions occurring during extrusion through the porthole dies, hence the obtained results are not much good for practical use. There are no weldability tests in which the temperature, unit pressure, welding time and deformations in the welding zone can be simultaneously controlled. It is necessary in the correct bonding test to provide the welding conditions without contact of air, which could oxidise of the metal streams. The paper presents the original device for the research of aluminium alloy weldability, reflecting the conditions of metal bonding (without air access), which occur in the welding chamber of porthole dies. This device is a modification of a previously patented device carried out in order to determine more precise basic welding parameters. The operation principle as well as the methodology for determination of susceptibility to welding of aluminum alloys has been presented, using the AlMgSi alloy as an example in the type of EN AW-6082. The welding conditions of the 6082 alloy were determined, which allowed for high quality bonding. A parameter describing the welding conditions was defined as the relationship of the normal welding stress to the yield stress (σn/k) and its values were determined at different temperatures. The obtained values of welding stress are the basis for the proper design of porthole dies.