Given a long good relationship I wouldn't expect them to do more than a new chunk of material, and only then if it's not a frequent thing. We can debate which direction the donuts should go. If this is one of the bigger issues you've had in that many years I'd say you're doing well.
Former job we had a higher volume (100k/year) sort of part where the incoming steel occasionally had a cold seam. Somewhere between finish machining and the end customer they part would just up and split in half at the seam every now and then. We would complain and the suppler of the blanks basically said:
1. We can send you a new blank in exchange for that one. Honestly though at 100k parts/year the cost of the blank isn't the issue.
2. We are willing to guarantee this doesn't happen, but only if we 100% radiology test the parts, you give us a spec., and pay for the cost of the testing.
3. Additional note that the mill we had making the steel was known for having this issue a bit more than others. We were buying mill runs of material, so that was a realistic thing to change. However, all other mills were more expensive (guess why), so there would be a cost increase to cover that delta.
At the end of the day we either kept complaining but did nothing, or changed the mill, I don't remember. We did put a note in future RFQs not to use that mill.
Point being, this falls under the cost of doing business. It's a risk you take. It can be avoided with material testing, but just eating it every now and then carries less direct costs than properly preventing it.
