You are a Boeing jobber. Your shop foreman shows you a complex hydroformed part with obvious irregularities. You tell him to work it up. A day later he returns. Xray, dimensional and penetrant testing are ok. consensus is "Luders Lines". No need to call Boeing. You know the answer to part acceptability lies within the mountain of paper provided each vendor. and 2 hours later the critical document is found. 5300-1.
Boeing's definition of Luders Lines:
"elongated surface marking or depression caused by non-uniform yielding of the material
during a stretching or forming operation"
and they are usually associated with temper state 5 (soft-soft).
No. 1 (hard)
No. 2 (half-hard)
No. 3 (quarter-hard)
No. 4 (skin-rolled)
No. 5 (dead-soft)
so, what is the Boeing position on submission of a part with Luders lines?
"Luders Lines are acceptable". BAC 5300-1 par. 11.4.11.
and with that you order beer and pizza for the crew
Lithium bearing alloys free of Luder ... - Google Patents