Influence of Preheated Wire on GMAW Process

An hot-wire GMAW process is proposed in which the wire is preheated by a TIG arc to enhance the wire melting, and the process is aimed at high efficiency welding with a low level heat input. The welding system is designed, the wire temperature is monitored and the metal transfer and arc behavior is observed. The preheating effect on the wire temperature is analyzed, and the influence of the hot wire on the metal transfer, arc behavior, and the weld formation are analyzed, compared with conventional GMAW. The results show that the preheated wire can significantly enhance the wire melting, and thus several beneficial effects on the GMAW process.

Effect of the Wire Temperature on the Weld Formation in GMAW

An arc-preheating wire GMAW process is proposed in this paper. The welding wire is preheated by a TIG arc to enhance the wire melting. As a result, the welding current is decrease. So the improved GMAW process is aimed at high efficiency welding with a low level heat input. In this paper, the welding system is designed. The wire temperature is measured by a pyrometer. The preheating current effect on the wire temperature is analyzed. In addition, the influence of the wire temperature on the weld current and weld formation are analyzed compared with conventional GMAW. The results show that the preheated wire can significantly enhance the wire melting. By increasing the temperature of the welding wire, the welding current decrease and the heat input of the base metal reduce accordingly. The shallow penetration and large reinforcement height are obtained at the arc-preheating wire GMAW process.

Experimental Study on GMAW with Strip Electrode

GMAW with strip electrode is a new method, which uses the flat wire with a rectangular cross-section to replace the conventional round wire as consumable electrode. In the present study, the welding system was established. Then the typical arc behavior and metal transfer were analyzed. After that, high-speed-high-current welding experiment was carried out in both GMAW with strip electrode and conventional round wire. The results show that, Compared with the conventional GMAW with round wire, the welding arc of GMAW with strip electrode has much lower arc pressure, and the impact of the droplet on the weld pool is weakened remarkably. These two characteristics make GMAW with strip electrode suitable for high efficiency welding on the basis of maintaining the original advantages of GMAW.

Improving productivity and quality in plastic and thin metallic plates manufacturing by using ultrasonic welding processes

The paper presents an overview of the research done at the Romanian National R&D Institute for Welding and Material Testing ISIM Timisoara in the field of ultrasonic process development. It starts with a general presentation of the value added by the welding sector in Europe. There are presented figures representing the size of the welding sector in Romania. The need of development of new high efficiency welding processes is mentioned, ultrasonic welding being one of the special welding processes with exceptional application perspectives. Practical examples of industrial application of the ultrasonic welding process for joining plastic and metallic materials are presented. A special case study refers to the welding of new shape memory alloys. The use of the ultrasonic welding instead of an conventional welding process has lead in each presented case study to an increase of the efficiency of the welding process through higher productivity and saving of manpower, consumable, energy.