When to replace Belville washers?

[southbury]

So, after 2 years of research.


When do Belleville washers need to be replaced?
Assuming I got this wrong on my exam.


answers were
every time
any deformation
after 25% deformation
50% deformation


answers need to cite a ANSI/IEEE/NETA etc document.
I would expect IEEE

and FYI actually contacted Belleville, They cite using "industry standard" i.e no answer

[SecondGen]

So, after 2 years of research.


When do Belleville washers need to be replaced?
Assuming I got this wrong on my exam.


answers were
every time
any deformation
after 25% deformation
50% deformation


answers need to cite a ANSI/IEEE/NETA etc document.
I would expect IEEE

and FYI actually contacted Belleville, They cite using "industry standard" i.e no answer

What was your answer? According to the author notes in this article, the answer is not "every time:" https://www.ecmweb.com/content/article/20890209/belleville-blues


I contacted two manufacturers, and they said reuse is application- specific. The differentiating factor is whether your Belleville has sharp edges or not (most Bellevilles do not). Belleville washers do not lose spring capacity. If a manufacturer says to reuse a Belleville, then doing so should result in no performance loss whatsoever.

My guess would be "any deformation" because any kind of deformation would affect its locking capabilities. If its too flat or warped it wont lock or seat properly.

How would you gauge if a washer is 25% or 50% deformed? That seems pretty specific and open to interpretation.

Sorry I don't have any documents to back this up, its just my take.