Fully clad stainless steel combines layers of metal through the base and sidewalls. Stainless steel supplies the cooking surface and strength; conductive materials such as aluminum improve heat conduction and heat distribution.
Typical 3-ply stainless steel sandwiches an aluminum core between layers of stainless steel. A 5-ply stainless steel design adds layers, but five does not automatically outperform three. Core thickness, overall thickness, pan shape, and burner fit matter.
A bonded disc base concentrates conductive material beneath the pot rather than throughout its walls. It can suit boiling and simmering; performance depends on disc coverage and construction. It does not inevitably scorch food. For either design, balance even heat with weight and comfortable handling.