At what temperature will metal expand?

Question

I've heard that metal expands when heated...i was curious at what temperature will this actually take place.

Answer 1

It happens at any and every temperature. it is small.

Steel, for example, will expand 12e-6/k. Which means that for a 1000 degree C temperature change, it expands 1.2%.

or 0.12% change if you heat it up by 100 degree C (180F), ie, a 10 ft rod will expand about 1/8 inch.

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Answer 2

It depends on the metal.  All matter begins to expand with the addition of energy; it makes the atoms within it move more.  As the atoms move more, the material expands, or, in the case of gases, pressure and volume increase.

The rate of expansion depends on how the bonds between the atoms/molecules are, in terms of condition, type, and other factors. Steel expands more readily than glass because the bonds in the molecules of glass pull together more than the molecules in steel.  Lead out-expands steel because it [the lead] has weaker bonds.

If you actually want to "see" material expand/contract/weaken bonds.  Try holding different types of metal over a flame, but do be careful.

Answer 3

It happens at any temperature. If you move a piece of metal from a cold room into a hot room, it will expand. But the effect is very small.