Spot Welding Electrodes

In the Integral Coach Factory, Madras there are nine spot welding machines used for welding thin sheets-steel and aluminium-in the construction of coaches. Fig. 1A shows a typical spot welding machine in operation where as Fig. 1B is the enlarged view of the electrodes in working condition. The electrodes used uptil 1963 were of imported variety since they were not manufactured in India The annual requirement of spot welding electrodes was to the tune of 227 kg. (500 lb.), the import of which involves a large amount of foreign exchange. As a consequence of non-receipt of electrodes in time by import, the production at times suffered greatly. What ever indigeneous tips were available were found to be not useful at all due to their short life and their difficulties in operation. As a result, low quality weld connection was obtained. To obviate the difficulties enumerated above and also to find out a fairly good substitute for the imported spot welding electrodes, attempts were made to manufacture the electrodes in I.C.F. by developing a suitable alloy. The experimental researches that were carried out for this purpose are described below, vide article entitled as above by Dr. G. Mukherjee, Chemist and Metallurgist, I.C.F. Madras. M. C. Nair, Asst. Chemist and Metallurgist, I.C.F. Madras, Y. K. Rau, Laboratory Supdt. Integral Coach Factory Madras in the Indian Railway Technical Bulletin, May 1963.