304L Grain Size Effect on Roll Forming

[nornrich]

All,

We have a specialty wire being roll formed and annealed. The wire is about 0.01" x 0.1" (hxw) in cross section. After rolling we then strip anneal the wire to minimize as many of the internal stresses, as we can. We are then stamping the wire with a bent leg of about 0.041". The wire rolling house is saying that a batch of the base round wire that we had trouble forming was a result of a larger grain size in the raw material. Does this pass the smell test? How would the grain size effect the stamping process, after the wire has been annealed?

Regards,

Rich.......

Richard Nornhold, PE

http://www.personna.com

 

[TVP]

Yes, it passes the smell test. Larger grains = less ductility/formability.

 

[metengr]

I am not sure you have provided enough information to pass a sniff test. What is the problem with forming? Cracking or surface finish????

 

[nornrich]

The problem with forming is we are trying to bend the leg and keep straighness on the finished part to +/-0.002" over 1.56". The different grain size is giving us a camber of about 0.125" over the length. Seems excessive and I would think highly dependent on the grain orientation being perpendicular to the bend line.



Richard Nornhold, PE

http://www.personna.com