TWI Industrial Member Report Summary 235/1984
By G A Hutt
The literature relating to recent developments in high efficiency gas shielded arc welding processes has been reviewed with particular reference to the welding of steels using narrow gap MIG and TIG techniques, high current MIG welding and the TIG hot wire technique. In the case of narrow gap welding, there appears to be active research and development work in progress aimed at providing a solution for some of the problems traditionally associated with the technique such as inconsistent sidewall fusion and poor tolerance to joint fitup. A feature of many of the recent narrow gap MIG and TIG systems has been some form of oscillation of the electrode to cause impingement of the arc on the side wall and current pulsing to control the weld bead shape and the overall process stability. A few systems also employ seam tracking and adaptive control further to improve the process tolerance. A second area of development are high deposition rate processes such as high current MIG welding and TIG hot wire welding which are being used to produce high joint completion rates whilst maintaining satisfactory weld properties through control of heat input. The benefits, disadvantages, process characteristics and application of these various techniques are outlined.