Address Heat Treating of Steel #233585

When we speak of seeing a metal under the microscope, we refer especially to our prepared sample that we are going to examine. We cannot take a fracture and look at it under a high power microscope, because in a fracture we would have high places and low places, and if we looked at it with a glass above 30 magnifications, we would probably have the moun tains in focus, but the valleys would not be, so that in order for us to study the structure of steel under the microscope it' is necessary for us to take our sample and polish it very highly, so that all the parts are on the same plane. After polishing we etch, that is, we apply a drop of acid and wipe it off quickly. The acid in that way brings out the demarca tion line between the grains or crystals, or has different action upon different crystals.