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This is a Type 416 martensitic stainless steel nut from a
large lot of similar nuts, of which one-third broke when they were
pinched to lock them onto their mating bolts. Type 416 has 0.15%C maximum, 12-14%Cr, and 0.07% S or Se minimum. Its hardness was Rockwell C24. The unbroken nuts averaged Rockwell C10. This is a longitudinal section through one side of one of the broken nuts. My photomicrograph was made at 500X. What's wrong here ? |
| Hint: You will
need to look up the properties of this alloy and relate its composition
to what you see above. The link to the Answer for this specimen is at the bottom of this page. |
| Answer: Follow this link. |