Gas metal arc welding

About: Gas metal arc welding is a research topic. Over the lifetime, 11706 publications have been published within this topic receiving 109555 citations. The topic is also known as: metal active gas welding & GMAW.

Problems in laser repair-welding a surface-treated tool steel

Abstract: A research work is described on the development of defects in laser repair welding of a surface-treated tool steel. Repair welding tests were carried out on plasma-nitrided and on chrome-plated type 1.2738 steel plates. Welding defects in the chrome-plated samples were mainly due to chrome and oxygen overalloying of the weld metal, leading to extensive hot cracking. Cracks of the surface chrome deposit in the HAZ due to welding stresses were also detected. In the nitrided samples, welding resulted in the copious formation of gas pores due to nitrogen release during weld metal solidification. A procedure for combined laser pre-treating and laser welding of the nitrided samples was thus presented. The procedure is aimed at minimising the negative effect of the laser beam on the structural integrity of the base and welded material. The results of the microstructural analyses revealed that a significant reduction in defects could be achieved by the proposed method in the nitrided samples.

Welding torch with a temperature measurement device

Abstract: Various welding systems including a welding torch assembly are provided. The welding torch assemblies may include a welding torch adapted to be utilized in a welding operation to establish a welding arc between the welding torch and a workpiece. The welding torch assemblies may also include a temperature sensing system integral with the welding torch and adapted to sense a temperature of the workpiece.

Plasma properties of helium gas tungsten arc with metal vapour

Abstract: The energy source characteristics of gas tungsten arc (GTA) strongly depend on the physical property of arc plasma. In welding processes, it has been experimentally confirmed that metal vapour evaporated from a high temperature weld pool drastically changes the property of arc plasma and decreases its temperature. However, the effect of metal vapour on the characteristics of heat flux into a base metal is still not clear owing to the difficulty in experimental studies of arc plasma. In the present paper, the energy source property of helium GTA mixed with metal vapour was numerically analysed. It was found that the intense radiation generated from dense metal vapour decreases heat flux into a base metal and contracts the current density distribution especially near the arc axis.

Weld microstructure and shape of laser–arc hybrid welding

Abstract: A series of CO2 laser–metal inert gas arc hybrid welding experiment was carried out to investigate the effects of laser/arc energy ratio and groove parameters on the shape and microstructure of hybrid weld The results showed that increasing arc current and groove cross-section area can reduce dimension difference of laser zone and arc zone by enhancing the uniform of energy distribution in molten pool The arc current can speed the melted metal flow to the pool root and drive more heat to the pool below by the arc pressure, and groove area can reduce the resistance of melted metal flowing to the pool root The microstructure of hybrid weld is simultaneously determined by the total line energy of hybrid welding and energy ratio of laser/arc (ER LA), and only under the proper or relatively smaller total line energy ER LA has obvious effects on microstructure Increasing the ER LA can increase the tendency of hybrid weld to obtain structure with higher hardness Furthermore, the mechanical performan