Modeling the Ferrite-Austenite Transformation in the Heat-Affected Zone of Stainless Steel Welds
The diffusion-controlled ferrite-austenite transformation in stainless steel welds was modeled. An implicit finite-difference analysis that considers multi-component diffusion was used. The model was applied to the Fe-Cr-Ni system to investigate the ferrite- austenite transformation in the heat-affected zone of stainless steel weld metal. The transformation was followed as a function of time as the heat-affected zone was subjected to thermal cycles comparable to those experienced during gas-tungsten arc welding. The results showed that the transformation behavior and the final microstructural state are very sensitive to the maximum temperature that is experienced by the heat-affected zone. For high maximum exposure temperatures ({approximately} 1300{degree} C), the ferrite formation that occurs at the highest temperatures is not completely offset by the reverse ferrite dissolution at lower temperatures. As a result, for high temperature exposures there is a net increase in the amount of ferrite in the microstructure. It was also found that if compositional gradients are present in the initial ferrite and austenite phases, the extent of the transformation is impacted.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 629295
- Report Number(s):
- ORNL/CP-95656; CONF-9709120-; ON: DE98001916; TRN: AD-a339 525
- Resource Relation:
- Conference: 1997 conference on numerical analysis of weldability, Graz (Austria), 29 Sep - 1 Oct 1997; Other Information: PBD: Dec 1997
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
THERMODYNAMIC PROPERTIES
TEMPERATURE RANGE 0065-0273 K
MICROSTRUCTURE
TEMPERATURE RANGE 0400-1000 K
THERMAL CYCLING
PHASE TRANSFORMATIONS
FERRITE
AUSTENITE
GAS TUNGSTEN-ARC WELDING
WELDED JOINTS
IRON ALLOYS
FINITE DIFFERENCE METHOD
NICKEL ALLOYS
DIFFUSION
CHROMIUM ALLOYS
HEAT
CHEMICAL COMPOSITION
VARIATIONS
HEAT AFFECTED ZONE
TERNARY ALLOY SYSTEMS