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U.S. Department of Energy
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Role of non-metallic inclusions in controlling weld metal microstructures in niobium microalloyed steels

Book ·
OSTI ID:6269446
In order to investigate the effects of inclusions on ferrite formation, submerged arc weldments were made using experimental chemical reagent grade fluxes from the CaF/sub 2/-CaO-SiO/sub 2/ system on a niobium microalloyed steel plate. Five filler wires of different compositions were used. Chemical and metallographic analyses were carried out to collect data on chemical compositions and microstructures of the weld metals. Scanning and transmission electron microscopy work was performed on inclusions extracted from the weld metals. The characterization of the chemical nature of the inclusions was done with an SEM/EDS unit. Direct relationships between (i) weld metal oxygen and inclusion content, and (ii) inclusion density and weld metal microstructure, were established in this investigation. This explains why it is possible to relate microstructure to the weld metal oxygen content instead of the inclusion density, which is fundamentally more correct.
Research Organization:
Colorado School of Mines, Golden (USA)
OSTI ID:
6269446
Country of Publication:
United States
Language:
English