Double-sided Welding Research Articles

Improved microstructure and properties of 6061 aluminum alloy weldments using a double-sided arc welding process

Due to its popularity and high crack sensitivity, 6061 aluminum alloy was selected as a test material for the newly developed double-sided arc welding (DSAW) process. The microstructure, crack sensitivity, and porosity of DSAW weldments, were studied systematically. The percentage of fine equiaxed grains in the fully penetrated welds is greatly increased. Residual stresses are reduced. Porosity in the welds is reduced and individual pores are smaller. It was also found that the shape and size of porosity is related to solidification substructure. In particular, a weld metal zone with equiaxed grains tends to form small and dispersed porosity, whereas elongated porosity tends to occur in columnar grains.

Solidification behavior of Al-Mg aluminum alloy using double-sided arc welding process

As popular aluminum alloys, the 5xxx Al-Mg series, such as 5050 and 5052, etc., are widely used in applications such as automobile, pressure vessels, armor plate, and components for marine and cryogenic service. In this, as in all non-heat-treatable aluminum alloys, the weld metal zone is considered to be the weakest part of the joint and is the location of failure when the joint is loaded in tension during welding [1]. Solidification behavior of the weld pool, which controls the microstructure of the weld metal zone, plays a critical role in determining the ultimate strength of the joint.

Automatic Welding of High Carbon Hoop Steels

At Chita Plant of Daido Steel Co. the butt welding of hoop steels, as the preparatory process, is being done aiming at improvement of efficiency and yield of cold rolling work of hoop steels.The welding has been done manually up to now under TIG method, but the raw material was such a high carbon steel whose weldability was poor and therefore, it was inclined to grow weld defects and there occured breaking accident very often around the weld zone during rolling.Therefore, we have made an investigate on automation of welding for the purpose of quality stabilization of weld zone.Considering that the part to be welded is, before rolling, to be made smooth after removing the reinforcement, the thickness of plate for welding, the most positive trial of making the weld zone into product, the processing at Chita Plant etc. We have come to adopt TIG method without using filler metal.If the plate thickness is up to 4.2mm the automation of a one side welding of I-butt by Ar or Ar plus H2 atmosphere is possible. For the plate thicker than the above mentioned, the double side welding method whose first pass is flat position is preferable.The above written method is now being tried experimentally at present and our purpose seems to be achieved efficiently.