1.2316 | X38CrMo16 +QT short-time nitrided

Cold work steel, here quenched and tempered and short-time nitrided.
Due to the high chromium content, no compound layer is formed during nitriding, only a diffusion zone. In this zone, the chromium has been consumed with the formation of chromium nitride, so that this zone can already be etched with Nital. The chromium-rich base material, on the other hand, is only attacked by the hot V2A pickle, which in turn etches over the diffusion zone.