Micro Cracks in the recast layer

I am a Metallurgical Technician and conduct evaluation on EDM parts with small features, holes metering slots, on different materials, I see microcracks on PH-steels and 440C steels, and I want to make sure my grinding and polishing process are not inducing some or any of these microcracks. I believe these are inherit in the process and when they appear on my polish mount, I take back to 600grit and repolish, and some disappear but no completely. So, question it seems to me that these microcracks are not continues but intermittent and this could be the reason why I see them, and they I don’t? is my rational here correct? can hot mounting pressure (400pis) curing process of my Bakelite and epoxy powder induced could cracking as well as my grinding process?