Microstructure Evolution in Resistance Spot Steel Welds
The microstructure development in resistance spot welds depend on the weld
thermal cycle characteristics. During heating cycle, various regions
of the steel sheet are heated to different temperature regions. This
leads to complete melting, complete austenitization, partial austenitization,
and tempering as a function of distance from the middle of the weld region.
These regions on cooling lead to significant microstructural gradients.
For example, the microstructure development
in a DQSK steel weld shows the presence of bainite and martensite in the
weld metal region. Therefore, the microstructure model must consider
the reactions during heating and cooling. Various microstructure
modeling approaches are being developed in this project. Details
of some of the models can be obtained from published literature.
Microstructure Model Based on Simultaneous Reaction Kinetics
