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How Are Utensils Made?

Most of us don't stop to consider our cutlery, except to ponder whether it's the knife or the spoon that gets the spot just right of the plate. But utensils are a marvel of modern metallurgy.

General-purpose forks, knives and spoons are made from steel, an alloy whose main ingredient is iron. An alloy is a solid mixture of two or more elements.

Iron's molecular structure makes it soft and easy to bend. The atoms are arranged into planes that can easily "slip" past one another if pushed. To make forks that won't end up looking designed by Dalí, one must strengthen the joints where the planes meet.

One way to accomplish this is to add carbon to iron, which produces steel. Steel's molecular structure is highly complex compared to that of iron, and it is much more difficult to make slips occur in iron that is evenly peppered with carbon atoms. Heated to a scorching 727°C, iron and carbon together form crystalline structures hard enough to handle mom's well-done brisket.

But the steel in your cutlery contains more than just iron and carbon. About 20 other elements are found in steel alloys. To make steel stronger and easier to harden, elements like vanadium and titanium are added. To prevent rusting, chromium and nickel are added to the steel. Metals with over 12 percent chromium are virtually rustproof: a thin layer of chromium oxide forms around the steel and prevents further oxidation.

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