Comparison of Al-Zn-Mg Alloy P-MIG Welded Joints Filled with Different Wires

Wang Dianlong,Diao Guangyun,Liang Zhimin

doi:10.1515/htmp-2017-0146

Wang Dianlong, Diao Guangyun + Show 1 more

Open Access

https://doi.org/10.1515/htmp-2017-0146

Copy DOI

Abstract

Abstract Three kinds of welding filler wires, named ER5356, ER5087 and ER4043, were used to joint 12 mm thick Al-Zn-Mg alloy plate by the pulsed MIG(P-MIG) welding. The microstructure and mechanical properties of the joints were analyzed and compared. The results showed that the average tensile strengths of the joints filled with ER5356, ER5087 and ER4043 were 294 MPa, 313 MPa and 237 MPa, respectively, and the average elongations were 7.9%, 7.6% and 1.6%, respectively. All the joints’s fracture locations were near the fusion boundary. The microhardness test showed that the locations of the lowest hardness were all in the center of cross section. The results revealed that the weld filler by ER5087 was consist of more columnar crystals of larger grain size, while the weld filled by ER5356 was consist of more equiaxed grains of smaller grain size. The microstructure of the weld by ER4043 was typical eutectic dendrites structure.

Highlights

Al-Zn-Mg aluminum alloy is an ideal high-strength structural material due to its high specific strength, good hot workability and corrosion resistance
The results revealed that the weld filler by ER5087 was consist of more columnar crystals of larger grain size, while the weld filled by ER5356 was consist of more equiaxed grains of smaller grain size
ER5356 and ER5087 welding wires had large amount of metal in the single weld, and the remelting effect of the previous weld pass on the first pass was obvious

Summary

Introduction

Al-Zn-Mg aluminum alloy is an ideal high-strength structural material due to its high specific strength, good hot workability and corrosion resistance. It is widely used in high-speed train body structure and aeronautical industry [1,2,3,4]. The ER5356, ER5087 and ER4043 welding filler wires produced by SAF-FRO were selected for PMIG welding of 12 mm thick Al-Zn-Mg aluminum alloy plate. Two plates with dimension of 350 mm by 150 mm were used for butt welding. Were three kinds of welding filler wires, which named ER5087, ER5356 and ER4043. ER &ER st pass nd through th pass welding Welding current speed (A) (cm.min− )

Experimental procedures

Results and discussion

Conclusions