This question already has an answer here:
I have a cylinder (imported from Creo, in .obj), to which I've added a material, steel and rendered it. It looks great.
I've now cut it in half, and want to see a different texture on the cut face, how do I do that in Cycles?
I tried diffent tutorials from that site but doesn't work with Cycles and imported .obj.
Here is an outside view:
Then, when cut, the blueish part should show the cutting tool path leaving marks in the metal.
Marks or scratches could be like this.