Residual Stress Evaluation in Vitreous Enameled Steel Sheets by Digital Images Analysis of Microstructures - Visual Computing: Scientific Visualization and Imaging Systems - page 175

Fig. 9.11 EDX maps relative to the interface between the coating and substrate

Figure 9.12 reports a detail of the F.E.M. discretization relative to a micrograph
analyzed in this study.
The analysis was performed by the simulation of the cooling of the material
from the maximum temperature reached during the manufacturing to the room
temperature, assuming a temperature gradient of 400 C. In particular, micro-
graphs of coatings representative of the two manufacturing processes before
described have been considered. The thickness of the steel sheet introduced in each
model is 0.8 mm. The first simulations did not took into account the presence of
the graded layer, as discussed before.
Figure 9.13 shows the gray-scale map of the thermal stress for a coating
manufactured with the wet enameling technique.
The figure reports the component of the residual stress in the longitudinal
direction, indicated in the figure as x. As for the boundary conditions, a longitu-
dinal length of the material three times that of the original image was considered in
order to demonstrate the stress build-up in a wide spread coating.
The stress contours show a steep variation at the interface between the coating
and the substrate, as also evidenced in the diagram of Fig. 9.14 a where the thermal
stress along with a vertical cross-section through the coating, in particular, relative