austenitic stainless steel sheets have gained wide acceptance in the fabrication of components, which require high temperature resistance and corrosion resistance such as metal bellows used in expansion joints in aircraft, aerospace and petroleum industries. in the case of single pass welding of thinner sections of this alloy, pulsed current micro plasma arc welding (pcmpaw) has been found bene...

Repair welding is not used enough in the industry 1 . One of the reasons for this lies in the insufficient and unrealiable knowledge in many segments of this area. A very important part is having appropriate knowledge of metallurgical processes in heating of the base material 2-4 . Unsuitable heating deteriorates the microstructure as it reduces toughness and fracture behaviour of the weld 5 . ...

This paper presents a solid freeform fabrication (SFF) technique based on micro-plasma powder deposition (MPPD). The relationship between the geometric features of the deposited layers and the welding parameters is investigated. The arc length is controlled through the monitoring of the arc voltage. The result of building parts with functionally graded components by the MPPD process is shown as...

in this paper, thermal effect of plasma arc welding is investigated, and temperature field of ferrite stainless steel is acquired. thermal effect of plasma arc and subsequently the generated temperature field in the work piece is the key for analysis and optimization of this welding process, which is the main goal of this paper. finite element simulation of welding process by simplec method and...

In regular arc welding, the arc heat is transferred from the surface of the workpiece to melt it. In keyhole plasma arc welding, the workpiece is melted by the plasma jet which heats the wall of the keyhole along the thickness direction. Penetration is achieved with reduced heat input. However, the plasma jet only gains its energy in the arc before reaching the keyhole. In the keyhole where no ...

This paper gives a recent progress of welding process research in Japan, especially, an instance in the capability of the visualization and prediction of welding arcs, though the dynamic observations of spectral image by a high-speed digital video-camera with a monochromator and also the calculations by numerical models. The dynamic observations lead to visualizations of metal vapor behavior in...

In order to study the effects of laser induced metal vapour on arc plasma during laser arc double sided welding (LADSW), emission spectroscopy techniques were utilised. The arc plasma in LADSW of 5A06 aluminium alloy was compared with conventional gas tungsten arc welding (GTAW) in this work. The electron temperature and density were estimated by the Saha– Boltzmann equation and the Stark broad...

This paper analyses the arc interference in an a.c. combined (both the pilot arc and the plasma arc exist in the welding process) plasma arc welding of aluminium alloys. This phenomenon results in an unstable welding process and weld formation. To maintain the pilot arc during the period when the electrode is positive, a cathode region must be formed in front of the tungsten electrode tip. Howe...

A unified comprehensive model was developed to simulate the transport phenomena occurring during the gas metal arc welding process. An interactive coupling between arc plasma; melting of the electrode; droplet formation, detachment, transfer, and impingement onto the workpiece; and weld pool dynamics all were considered. Based on the unified model, a thorough investigation of the plasma arc cha...

Keyhole plasma arc welding is a unique arc welding process for deep penetration. To ensure the quality of the welds, the presence of the keyhole is critical. Understanding of the keyhole will certainly benefit the improvement of the process and weld quality. Currently, the size of the keyhole is assumed to be correlative with the robustness of the keyhole process in maintaining the keyhole. To ...