A quiz : metallurgist?

Smaller.

The hole will become larger because metal expands when you heat it. For example, if the metal sheet was a circle of 6 inches in diameter, when heated the metal might measure 6.025 inches in diameter. The hole in the center of the metal is of "X" diameter. When the metal expands the new hole diameter will be "X plus Y", where Y is the amount of expansion.

Consider that a common method of freeing rusted metal joints is to heat the larger and cool the smaller of the two. This creates a gap between the large, and the small one, permitting tools to be used to separate them.

Ahh, the great conundrum.

When metal is heated it expands, thus the hole should be smaller, however, if you need to press fit a bearing onto a rod, you apply heat so the hole becomes bigger. So, which is it.

In industry, when you need to pressfit to pieces, lets say, press a steel pin into a hole, you heat the female side and freeze the male component. Thus, with the application of heat, the hole is bigger. It is hard to understand, however, the hole will, indeed get bigger. Just ask any machinist.

It will get smaller. Think of it like cooking a donut. As the donut heats up it expands making the hole in the middle smaller. Metal expands as it heats up so the effect will be the same.

Initially the hole will expand. Because the metal material will expand from a solid state towards the liquid state. If you continue to heat it longer to the liquid state. The hole will start shrinking as the metal becomes a liquid.

Try it out and see.

Removing a metal disc from a sheet does not change the expansion of the sheet (i.e. the sheet will not expand into the space taken up by the missing material)

it will be smaller as the metal will expand on heating

will be greater

cause it will getting bigger by heat

smaller

greater