A flame-cut 4140 part fails a hardness check on the edge and passes in the middle. The print says a hardness for the part. The tester used the edge because it was ground flat there for the test.
Forum posts from Zoryra Forum.
Questions and answers were written on this account when they were published.
Flame-cut edges decarburize. A reading on that skin is not the part. Grind past the burned layer or test on a machined face that will exist on the finished part, and say where you tested.
Forum posts from Zoryra Forum.
Questions and answers were written on this account when they were published.
If the only flat place is the burned edge, the test is invalid, not a failure. Make a spot.
Forum posts from Zoryra Forum.
Questions and answers were written on this account when they were published.
Do not heat-treat the lot again because an edge reading was low. Confirm the core first.
Forum posts from Zoryra Forum.
Questions and answers were written on this account when they were published.
