TY - JOUR
T1 - Effects of Nb on the microstructure and corrosive property in the Alloy 690-SUS 304L weldment
AU - Jeng, S. L.
AU - Lee, H. T.
AU - Rehbach, W. P.
AU - Kuo, T. Y.
AU - Weirich, T. E.
AU - Mayer, J. P.
N1 - Funding Information:
The current authors gratefully acknowledge the support provided to this study by the National Science Council (NSC) of the Republic of China, Taiwan under Grant Nos. NSC-TPC-E-006-013 and NSC 89-2216-E-006-065, and the Sandwich Program between NSC and German Academic Exchange Service (DAAD).
PY - 2005/4/25
Y1 - 2005/4/25
N2 - A study of the microstructure and corrosion of dissimilar weldments of Alloy 690 and SUS 304L with various additions of niobium (Nb) (0.1, 1.03, 2.49, and 3.35% by weight) in the flux of coated electrodes is presented. With identical welding parameters and procedures, the weldments were butt-welded in three layers by shielding metal arc welding (SMAW), with each layer being deposited in a single pass. The results show that the dendritic microstructure in the fusion zone changed from a cellular to columnar dendrite and equiaxed dendrite with increasing Nb addition. Furthermore, the interdendritic phase increased in volume and changed in composition from an Al-Ti oxide to a mixture of Nb-Si phase and Nb-rich phase. Nevertheless, it was clearly observed that Cr7C3 precipitated at the grain boundaries of the low Nb weldment root pass. Finally, the results revealed that corrosion occurs primarily at the grain boundaries and within the interdendritic regions of the weldements irrespective of the level of Nb addition. For the region of abundant formation of Nb-rich phase, the high-Nb weldment had a relatively low corrosion resistance.
AB - A study of the microstructure and corrosion of dissimilar weldments of Alloy 690 and SUS 304L with various additions of niobium (Nb) (0.1, 1.03, 2.49, and 3.35% by weight) in the flux of coated electrodes is presented. With identical welding parameters and procedures, the weldments were butt-welded in three layers by shielding metal arc welding (SMAW), with each layer being deposited in a single pass. The results show that the dendritic microstructure in the fusion zone changed from a cellular to columnar dendrite and equiaxed dendrite with increasing Nb addition. Furthermore, the interdendritic phase increased in volume and changed in composition from an Al-Ti oxide to a mixture of Nb-Si phase and Nb-rich phase. Nevertheless, it was clearly observed that Cr7C3 precipitated at the grain boundaries of the low Nb weldment root pass. Finally, the results revealed that corrosion occurs primarily at the grain boundaries and within the interdendritic regions of the weldements irrespective of the level of Nb addition. For the region of abundant formation of Nb-rich phase, the high-Nb weldment had a relatively low corrosion resistance.
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U2 - 10.1016/j.msea.2005.02.042
DO - 10.1016/j.msea.2005.02.042
M3 - Article
AN - SCOPUS:17644410392
SN - 0921-5093
VL - 397
SP - 229
EP - 238
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
IS - 1-2
ER -