Advances of Research for Austenitic-bainitic Ductile Iron Welding

In this paper,the research in last decade are introduced, especially in metallurgy of welding, charcteristics of austempering heat treatment and welding process,the way of producing austenitic-bainition and its new welding consumables. Austenitic-bainitic ductile iron weld metals can be obtained by austempering heat treatment or in as-welded condition. For the former,research activities are mainly focused the effect of alloying elements on the chilling tendency of ductile iron wled,the characteristics of isothermal transformation and microsturcture of ductile iron weld metal,the effect of austempering heat treatment conditions on the microsturcture and mechanical properties of austenitic-bainitic ductile rion weld metal,etc. For the latter, the attention is into teh influnces of chemical composition and cooling rate on the microstructure and mechanical properties of as-weld austenitic-bainitic ductile iron weld metal. Some new welding consumables for welding of austenitic-bainitic ductile iron have been developed here, and the microstructure and mechanical properties of the weld metals can match those of austenitic-bainitic ductile iron.