Solidification of an alloy 625 weld overlay
- Lehigh Univ., Bethlehem, PA (United States). Energy Research Center
The solidification behavior (microsegregation, secondary phase formation, and solidification temperature range) of an Alloy 625 weld overlay deposited on 2.25Cr-1Mo steel by gas metal arc welding was investigated by light and electron optical microscopy, electron microprobe, and differential thermal analysis techniques. The overlay deposit was found to terminate solidification at {approx}1,216 C by a {gamma}/Laves eutectic-type reaction. The Laves phase was highly enriched in Nb, Mo, and Si. The solidification reaction and microsegregation potential of major alloying elements in the overlay deposit are compared to other Nb-bearing Ni base alloys and found to be very similar to those for Alloy 718. Solidification cracks observed in the overlay were attributed to the wide solidification temperature range ({approx}170 C) and formation of interdendritic ({gamma} + Laves) constituent. Reasonable agreement is obtained between the calculated and measured volume percent ({gamma} + Laves) constituent with the Scheil equation by treating the overlay system as a simple {gamma}-Nb binary and using an experimentally determined k{sub Nb} value from electron microprobe data.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 413291
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 27, Issue 11; Other Information: PBD: Nov 1996
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
20 FOSSIL-FUELED POWER PLANTS
INCONEL 625
GAS METAL-ARC WELDING
SOLIDIFICATION
TURBINES
MATERIALS
CHEMICAL COMPOSITION
SUBSTRATES
STEEL-CR2MO
OPTICAL MICROSCOPY
ELECTRON MICROPROBE ANALYSIS
DIFFERENTIAL THERMAL ANALYSIS
TEMPERATURE DEPENDENCE
PHASE STUDIES
SEGREGATION
CRACKS
DENDRITES