Material basics
What is cookware clad metal and how is it used?
Clad metal is a single sheet made from two or more metals bonded under heat and pressure, so the finished sheet behaves like one material while each layer keeps its own properties. In cookware, the point is to put the right metal on each face and a conductive metal in the middle.
The three jobs in a cookware sheet
Every clad cookware material answers three questions. What touches the food, what carries the heat, and what meets the hob.
The food-contact face is stainless, usually SUS304, chosen for corrosion resistance and cleaning. The core is aluminium, usually AL1050, chosen because it conducts heat far better than stainless. The hob face is a magnetic stainless, usually SUS430, because an induction coil only couples with a ferromagnetic material.
None of those three metals can do all three jobs alone. Stainless is durable but a poor conductor. Aluminium conducts well but is soft and reacts with food. A magnetic stainless is needed for induction but is not the surface you want to cook on. Bonding them solves all three at once.
Why the layers do not separate
A clad sheet is not glued. The layers are cleaned, stacked and bonded under heat and pressure, then rolled together so the interface becomes a metallurgical bond rather than a mechanical one. Done properly, the bond survives rolling, cutting, deep drawing and the thermal cycling of cooking.
That is also why the bond is the first thing to test, and why a clad supplier should be able to state the test method and the acceptance criteria for the structure you are buying. A bond that fails shows up as a blister or a separation at the draw radius, usually after the pan is formed, which is the most expensive moment to find it.
How it is used in a cookware factory
The material arrives as a disc, a blank or a sheet. The factory deep draws it into a body, trims it, attaches the handle, and finishes the surface. Some factories polish the cooking face; others buy the material already embossed or etched so the pattern survives assembly.
The thickness ratio is what the factory works with. A thicker aluminium core spreads heat faster but makes the pan heavier and the draw harder. A thinner core is lighter and cheaper but shows a hot spot on a high flame. Getting that ratio right for the product is the whole specification conversation.
Questions
Common questions
Is clad metal the same as a sandwich base?
No. A sandwich base is a separate disc bonded or welded onto a pan bottom. Clad metal is a full sheet with the layers bonded through its whole area, so the body and the base are the same material.
Does clad metal work on induction hobs?
Yes, if the hob face is magnetic, which is why 430 stainless appears there. An all-304 structure couples poorly with an induction coil.
Is clad metal dishwasher safe?
The stainless faces are, in the usual domestic sense. Repeated dishwasher cycles affect surface appearance more than structure, and the pan maker's care instructions apply.
Can clad metal be used without a non-stick coating?
Yes, and most clad cookware is uncoated. It is not non-stick in the coated sense; it relies on temperature control and fat.
Which structure is most common?
Three-ply 304 + 1050 + 430, because one structure covers gas, electric and induction hobs.