پديدآورندگان :
Silvayeh Z. zahra.silvayeh@tugraz.at Ph.D. student, Graz University of Technology, Institute of Materials Science, Joining and Forming, 8010 Graz, Austria; , Fellner B. Senior Scientist, Magna Steyr, Magna Steyr Fahrzeugtechnik AG Co KG, 8041 Graz, Austria , Hartmann M. Senior scientist, Austrian Institute of Technology, Light Metals Technologies Ranshofen (LKR), 5282 Ranshofen, Austria , Sommitsch C. Professor, Graz University of Technology, Institute of Materials Science, Joining and Forming, 8010 Graz, Austria
كليدواژه :
Aluminum Sheets , Welding , E , Coating , Heat Affected Zone , Mechanical Properties.
چكيده فارسي :
The properties of the heat affected zone (HAZ) close to the weld are strongly influenced by the welding process and by the post-weld heat treatment. The objective of this work was determining the width and the mechanical properties of the HAZ in Cold Metal Transfer (CMT) welded sheets of aluminum alloy EN AW 6063 T6 for three joint configurations: 20 mm lap-, 90°- and 45°-joints. During the CMT welding process the temperatures at defined distances from the joint were measured using thermocouples. Since the weld and the HAZ were inaccessible for direct measure-ments, the temperatures occurring there were calculated with the aid of a finite element model representing the welding process. Dilatometer samples for tensile testing were heated and quenched based on the temperature curves determined inside the HAZ. Some of these samples were also heat treated according to the electro-phoretic coating (E-coating) process. Hardness measurements revealed that hardness decreases by approx. 1/3 inside of both the weld and the HAZ compared to the uninfluenced sheet metal. Tensile tests confirmed that increasing the temperature peak inside of the HAZ decreases the strength, but increases the strain. However, this effect was less pronounced in the samples exposed to E-coating heat treatment. The weakest zone was found where temperature peaks of approx. 400 °C occurred.
