Figure 7. Contour plots of hardness properties responding to (a) Ra1 and immersion time, (b) Ra1 and wall thickness. (c,d) a 3D view of hardness properties, interaction with the respective parameters.

Figure 7. Contour plots of hardness properties responding to (a) Ra1 and immersion time, (b) Ra1 and
wall thickness. (c,d) a 3D view of hardness properties, interaction with the respective parameters.