Knowledge check (8 of 8)
100%
Lesson 07·QC and inspection
Reading a microsection — white layer, diffusion zone, and what the photo isn't telling you
How to look at a vendor's etched cross-section and microhardness traverse, what a porous compound layer means, and which case-depth definition is on the certificate.
9 min readLesson 7 of 12
Knowledge check
A vendor sends a one-page certificate with a 500× photo of an etched cross-section showing a 14 µm white band over a darker etched zone, plus a single number: 'case depth 0.020 inch (0.51 mm).' No etchant is named, no traverse is attached, no definition of case depth is cited. What do you ask for before accepting the part?