Spring failure reasons 3

[hamsuplo]

I have some returned springs that look like picture 3 and 4. There are many ways that the spring user could have misused it so that it turns into picture 3 or 4. But I have to assume that the spring user used it as meant to be used and that the failure is 100% due to the procedures before it gets to user (ie, metal producting, spring manufacturing, transportation)

We've been supplied by the same spring factory for the past decade, but only in the past year did we start receiving lots of returns of failed springs. So, obviously they have changed something in their manufacturing process which lowers the quality of their springs.

If anyone can give me some ideas why the spring would fail as it does in picture 3 or 4 (only one loop fails), I would appreciate it. Thanks in advance.

pictures of:
1. spring
2. how a spring is expected to deform under lateral deflection
3. what the spring I have looks like
4. another spring I have

 

[Tmoose]

Are some of the (rare) failed springs still around? I think only they know why they failed.
Maybe even talking to the customer returning springs could offer some insight, although I mostly expect to hear "I didn't do nuthin' "

Sometime to facilitate installing a spring folks will lengthen the spring. One way is to Bend he spring to open the coils on one side, inserting washers in the open coils, then bend the spring the other way and insert more washers. If this was done cruelly a modified version of 4 could result.