MICROSTRUCTURE OF DISSIMILAR JOINTS BETWEEN DUPLEX STAINLESS STEEL AND LOW ALLOYED STEEL

Extending the application area of Duplex stainless steels has led to the necessity of creating components or structures made of dissimilar materials. Due to the differences in the microstructure, the welding of the dissimilar steels is more difficult than that of similar steels. The research carried out in the current paper focuses on the particularities of completing the heterogeneous welded joints between a Duplex stainless steel and a Cr-Mo low alloy steel using as additional material an electrode wrapped in E 309MoL - 16, which contains approx. 23 % Cr, 12 % Ni and 2%Mo. The implementation of this welding technology focuses on eliminating the technological operations of preheating and post welding heat treatment, which is mandatory for welding low alloy steels sensitive to hardening through martensitic transformation and cold cracking respectively. Based on the Schaffler model a prediction of the metal microstructure deposited by welding is carried out and the quality of the joints made is carried out by metalographical investigations.