This is my first post on this forum because I have a question that I cannot seem to answer myself. At my working place we have a machine where a metal conveyor belt is running through a section of the machine where the temperature is constant at 320 degrees Celcius. On this conveyor belt are metal round disks with a hole in the middle. I know that when such a disk is heated from room temperature to higher temperature, the inner diameter of the disk (so in fact the diameter of the hole) gets smaller (right ?) I also know that the outside diameter of the disk itself will get larger. But the question is: how do I calculate this ? Let's say the outer diameter of the disk is 10 cm and the inner diameter of the hole is 8 cm at room temperature. How do I calculate these diameters at 320 C. I need an answer badly because inside the hot part of the machine there is resitricted space and we want to put disks through the machine that fit at room temperature, but we are not sure if they fit at high temperature. We can easily test this, but there is a risk that we damage the machine if the disks would become to large. The disks are in the machine long enough to reach 320 C themselves before they arrive at this restriction. Many thanks in advance.