Knowledge check (7 of 7)
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Lesson 07·Process sequencing
EDM after heat treat — recast, stress, and the nitriding handoff
Why the EDM recast layer ruins a downstream nitriding job, what to specify for Ra and recast depth, the required stress relief between EDM and nitriding, and how the most common shop-floor screwup produces a cavity that spalls in under 5,000 hits.
8 min readLesson 7 of 13
Knowledge check
A press die builder finish-EDMs a closed-cavity H13 die at 50 HRC using normal sinker settings, sends it straight to the nitride house, and the part comes back with a clean certificate (surface HV 1050, case depth 0.32 mm per DIN 50190, compound layer 6 µm). The cavity spalls at 4,200 hits. Walk through what happened and what was supposed to happen between EDM and nitride.