Similar and Dissimilar Welding of Ductile Cast Iron

In this research an experimental study has been carried out to investigate various procedures for welding ductile cast iron (DCI) by similar and dissimilar welding. Preliminary experiments were conducted which showed failed welded specimens in many cases where shielded-metal arc welding (SMAW) process using AWS 6013 welding electrodes was employed. In the light of these results, new and modified welding procedures were applied using both SMAW and tungsten inert-gas (TIC) welding processes for both similar and dissimilar joints. Dissimilar joints included joints with a combination between DCI and ST37 and DCI with stainless steel 304 (ST. ST. 304). There was dissimilarity not only in the welded steel type but also in the welded thickness. A variety of different thicknesses was joined together; namely 6, 7 and 8 mm plate thicknesses. Welded specimens were tested visually at the beginning. Then, examination of both microstructure and microhardness of welded joints were carried out. Tensile strength, macrohardness and impact value for selected welded specimens were determined and compared with microstructure and microhardness results. Successful similar and dissimilar welded joints proved the applicability of using the new welding techniques for DCI.