Influence of Current Feeding Position of Duplex Current Feeding MIG Welding on Droplet Heat Quantity.

Atsuhito Aoki,Shinichi Tashiro,Hideaki Kurokawa,Manabu Tanaka

doi:10.3390/ma12213590

Atsuhito Aoki, Shinichi Tashiro + Show 2 more

Open Access

https://doi.org/10.3390/ma12213590

Copy DOI

Journal: Materials	Publication Date: Oct 31, 2019
Citations: 4	License type: CC BY 4.0

Affiliation: Osaka University, Kawasaki Heavy Industries (Japan)

Abstract

Pure argon metal inert gas (MIG) welding is expected to offer the possibility to obtain high toughness weld joints. However, due to its arc instability and low wettability, it is difficult to apply pure argon MIG to a practical welding structure. In order to solve these problems, an improved MIG welding process with a duplex current feeding (DCF-MIG) mechanism was developed. In the DCF-MIG process, the welding current and the wire feeding speed are independently controlled by an additionally feeding secondary current from a secondary power source. Thereby, DCF-MIG can supply a large current compared to conventional MIG under the same deposition rate. In this study, to consider the influence of the secondary current feeding position of DCF-MIG on droplet heat quantity, droplet heat quantity was measured by calorimetry. As a result, the droplet heat quantity was found to be increased significantly with the increase of the distance between the primary current feeding point and secondary current feeding point. The increase of the droplet heat quantity in the DCF-MIG process had a strong effect on improving bead shape and penetration. The droplet heat quantity with the effective current value of DCF-MIG was derived from the simplified calculation and the results roughly agreed with the experimental data.

Highlights

Both the strength and toughness of weld joints must be ensured for the safety of steel structures used at low temperature, such as Liquefied Natural Gas (LNG) tanks [1,2]
The droplet heat quantity with the effective current value of DCF-metal inert gas (MIG) was derived from the simplified calculation and the results roughly agreed with the experimental data
Metal inert gas (MIG) welding is a highly efficiency process, but the process tends to be unstable in pure inert shielding gas

Summary

Introduction

Both the strength and toughness of weld joints must be ensured for the safety of steel structures used at low temperature, such as Liquefied Natural Gas (LNG) tanks [1,2]. For this purpose, tungsten inert gas (TIG) welding, which is able to obtain stable welding using pure inert shielding gas, is mainly used. It is required to develop a stable arc MIG welding process with pure inert shielding gas to achieve both high quality of weld joints and high efficiency.

Methods

Results

Discussion

Conclusion