Failure modes — white-layer spall, network cracking, distortion, embrittlement

A stamping die comes back from a six-month production run with the case sheeting off the working surface in flakes the size of a fingernail. The vendor's first response is "could be hydrogen embrittlement, we recommend a 200°C bake on the next batch." The shop pays for the bake. The next die fails the same way. This lesson covers the five real failure modes of nitrided tools, how to read each one off a microsection, and which ones a vendor will reach for when the actual cause is their recipe.