About this Abstract |
Meeting |
2021 AWS Professional Program
|
Symposium
|
2021 AWS Professional Program
|
Presentation Title |
A Model for the Ferrite-to-Austenite Formation during Continuous Heating in a Low Carbon Pipeline |
Author(s) |
Alejandro Hintze Cesaro, Patricio F. Mendez |
On-Site Speaker (Planned) |
Alejandro Hintze Cesaro |
Abstract Scope |
It is widely acknowledged that austenite formation is susceptible to the heating rate and initial microstructure. The kinetics associated with the chronologically first phase transformation in the HAZ may present significant differences depending on the many welding variables involved. Then, the completion of the transformation, hence the extension and the characteristics of the HAZ (product of the austenite decomposition), will depend on how the phase boundary moves.
Depending on the heating conditions, different mechanisms may prevail with varying driving forces involved, leading to different transformation rates. The present work attempts to identify the mechanisms and driving forces involved in austenite formation for two different heating rates to create later a mathematical model to predict kinetics for a broader range of heating conditions.
Experimental work together with theoretical calculations was performed to rationalize the influence of the mobility of alloying elements during continuous heating to provide a framework to describe the driving forces of the transformation. Thus, specific calculations were carefully performed to calculate molar Gibbs free energies and chemical potentials under different forms of equilibrium.
Ultimately, a mathematical model is proposed to describe the ferrite-to austenite transformation kinetics based on different asymptotic regimes identified and used as a base to calculate the driving force for the developed model. |
Proceedings Inclusion? |
Definite: Other |