How to calculate length change of material

[pckelly44]

Hello all,

Working on running parts through a swage die to reduce the OD of the part. The piece is not run completely through the die however, only about 75%. Part of the difficulty is determining how much the part will elongate axially. IS there any good method for determining this? Most of the parts are 520 DOM.

Thanks

 

[dhengr]

Pckelly44:
That material is not very compressible, is it? So the volume doesn’t change much, does it? Then where does that volume (dia./round area/length) change go if not to length change? You know the original O.D. and length, you know the finished shape of the portion that has not gone through the die, and the difference must go to length increase. Except maybe for a little waste and some minor bulging at the transition btwn. original and new dia.

 

[Cockroach]

Conservation of mass that is redistributed in an alternate geometry. Simple.

Regards,
Cockroach

 

[pckelly44]

I would have thought it was that simple too...but the calculations do not correspond with actual results. Further investigation shows other factors in play that I have yet to figure out. I was hoping there was something I was overlooking. Thanks