TWI Industrial Member Report Summary 702/2000
S W Kallee
Although the original patents and publications on magnetically impelled arc butt (MIAB) welding date from the 1940s, significant exploitation has only really occurred since 1970. The process is commercially applied mainly to joining mild steel tubes and/or cast iron parts. The automotive industry uses it for example to produce axles, benefiting from the very short cycle times and thus high productivity. Automotive, aerospace and oil exploration companies are now considering whether the process could also be applied to aluminium space frames, titanium tubular structures and stainless steel tubes.
Little progress has been made with aluminium and stainless steel alloys so far. Historically, the problems encountered when welding such materials have been ascribed to inadequate power sources, unsteady arc rotation, low rates of axial displacement, unsatisfactory gas shielding and a lack of reproducibility. Commercial machine producers saw also a conflict in the relatively long gas purging time compared to the short welding cycle. It is now believed that improvements in power source technology, control systems, magnetic coil designs and gas shielding will provide opportunities for significant improvements in the process when welding these materials. TWI has a vertical MIAB machine, which has been built especially for welding non-ferrous tubes and is currently developing welding procedures for these materials. This report describes modifications made to the machine to improve its operational capabilities.
- To develop improved systems for MIAB welding of thin wall tubulars of non-ferrous materials and stainless steels.