Influences of weaving parameters on dynamic characteristics and stability control of the droplet transfer in arc-weaving P-GMAW process

Di Wu,Huabin Chen,Yuxi Chen,Shanben Chen

doi:10.1007/s00170-021-08193-x

Abstract

The dynamic characteristics of droplet transfer are extremely complicated with the combined effects of gravity force and weaving motion during the weaving vertical-up welding on thick plate. In this paper, we firstly observed the droplet transfer behavior under various weaving parameters with high-speed photography and electrical signals during pulsed gas metal arc welding (P-GMAW). Then, we investigated the influences of different weaving parameters on the arc shape and molten pool as well as droplet characteristics. By establishing a novel weaving-force model based on state force balance theory (SFBT), we further revealed the drop transfer mechanism in weaving P-GMAW process. Extensive experimental results demonstrated that the suitable weaving parameters could effectively improve the droplet transfer stability and suppress welding defects including incomplete root penetration and lack of sidewall fusion. The findings of this paper will provide a basis for enhancing the welding process stability and obtaining a high-quality weld joint.

Highlights

With a series of advantages including the high melting efficiency, high penetration force and enough flexibility, gas metal arc welding (GMAW) technique has been employed widely, especially in the welding production of large-scale thick plate of high-strength low-alloy (HSLA) steel [1]
Droplet transfer, namely the course of liquid metal transfer from the electrode tip to the workpiece can significantly impact the stability of the molten pool, the degree of weld penetration and spatter rate, thereby further affect the welding process stability and weld quality [2]
The forces acting on droplet can be changed by adjusting weaving frequency to achieve a stable droplet transfer and avoid the incomplete root penetration of thick plate

Summary

Introduction

With a series of advantages including the high melting efficiency, high penetration force and enough flexibility, gas metal arc welding (GMAW) technique has been employed widely, especially in the welding production of large-scale thick plate of high-strength low-alloy (HSLA) steel [1]. Monitoring and control of the droplet transfer behavior in GMAW process are one means of obtaining a desired weld quality on thick plate. Ghosh et al [5, 6] revealed that a pulsed spray transfer can be achieved when the average current is less than critical current during the pulsed gas metal arc welding (P-GMAW) process. It is difficult and time-consuming to determine the optimal pulsed parameters for obtaining a high-quality weld joint due to the larger number of controlling parameters. The complicated dynamic characteristic of droplet transfer during P-GMAW process has been a difficult research problem in the fields of welding manufacturing for half a a century

Methods

Results

Conclusion