The increasing demand for achieving high-efficiency and high-quality medium-thick aluminium alloy welded structures, especially large scale aerospace components, presents an urgent challenge to the conventional TIG arc welding process. This work proposed a novel double-pulsed variable polarity tungsten inert gas (DP-VPTIG) arc, in which square wave current was simultaneously modulated into ultr...

Gas tungsten arc welding is fundamental in those industries where it is important to control the weld bead shape and its metallurgical characteristics. However, compared to the other arc welding process, the shallow penetration of the TIG welding restricts its ability to weld thick structures in a single pass (~ 2 mm for stainless steels), thus its productivity is relativity low. This is why th...

In this paper a monitoring system that simplifies the finding of optimal welding parameters, the analysis and the optimisation of pulsed gas metal arc welding is described. The system allows the visual online observation of all states of the process, including the droplet transfer, without an additional lighting unit. Additionally, the measurement of electrical welding parameters during image r...

Plates of 3–5 mm in thickness were extracted from an AZ91D ingot and then butt joints of the plates were produced using tungsten inert gas (TIG) welding method. The TIG arc was also used to deposit welding beads on some of the thin plates. No cracking was found in the butt joints. However, hot cracking was always observed to propagate from the heat affected zone (HAZ) under the welding bead int...

Abstract: During the last decade, the demand for natural gas has steadily increased for the prevention of environmental pollution. For this reason, many liquefied natural gas (LNG) carriers have been manufactured. Since one of the most important issues in the design of LNG carriers is to guarantee structural safety, the use of low-temperature materials is increasing. Among commonly employed low...

AbstructThis application paper addresses the control of a nonminimum-phase plant with variable large orders and delays. The process concerned is full penetration gas tungsten arc welding. Based on an analysis of accepted adaptive algorithms, the generalized predictive control algorithm presented by Clarke et al. is selected as the principal control strategy. An adaptive generalized predictive d...

Cracking is a major concern in welding aluminum alloys. Although weld solidification cracks can be eliminated through addition of filler alloy, the additives modify the alloy or base-metal constituents and may not always be desirable. High-energy beam processes, such as electron-beam welding, that result in minimal heat input reduce crack sensitivity, but their high cost limits their applicatio...