Study on the Decoupled Transfer of Heat and Mass in Wire Variable Polarity Plasma Arc Welding.

Fan Jiang,Shinichi Tashiro,Cheng Li,Bin Xu,Shujun Chen,Manabu Tanaka

doi:10.3390/ma13051073

Abstract

A hybrid arc-wire welding method based on the variable polarity plasma arc (VPPA) and variable polarity pulse metal inert-gas (VP-PMIG) was proposed for manufacturing aluminum alloys. This paper aims to clarify the decoupling control process of heat and mass transfer in the hybrid welding process. To understand the arc physics and analyze the mass transfer behavior, the hybrid arc shape and droplet cross-sectional area with different parameters were obtained by high speed video photography. Further, the melting area of the base metal was analyzed by macro-metallography of the weld bead cross-section to study the heat transfer. It is found that the hybrid arc shape changes with time. The VPPA main arc is deflected to one side by the VP-PMIG, making the temperature distribution asymmetric, and during the VP-PMIG pulse necking occurs. The cross-sectional area of the droplet is more obviously affected by the VP-PMIG current than the VPPA current. Meanwhile, the VPPA current dominates the melting area of the base metal. Therefore, we conclude that heat transfer to the base metal is from the VPPA, while droplet transfer is mainly controlled by the VP-PMIG arc. These conclusions are confirmed by analyzing the decoupling degree of heat and mass transfer of the base metal by the VPPA and VP-PMIG arc.

Highlights

Within industrial development, aluminum alloys are widely used in aerospace, machinery manufacturing and other fields [1]
Jiang et al [5] designed a set of devices which can measure the instantaneous heat transfer of the variable polarity plasma arc (VPPA) to the base metal
To welding understand the characteristics of theThe hybrid arc and droplet transfer during one(EP)

Summary

Introduction

Aluminum alloys are widely used in aerospace, machinery manufacturing and other fields [1]. The arc welding process is one of the most widely used manufacturing methods for aluminum alloys [2]. Due to the special material properties of aluminum alloy, the heat and mass transfer of aluminum alloy welding is very important [3]. The heat and mass transfer in the welding process of aluminum alloy has always been a research hotspot. Some researchers use some special methods to study the heat and mass transfer in welding process of steel. Jiang et al [5] designed a set of devices which can measure the instantaneous heat transfer of the variable polarity plasma arc (VPPA) to the base metal

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Conclusion