Stainless steel forming

[stat65]

I have a formed sheet metal component in a ATV muffler that is spec'd as 409L (1.2mm thick). It is a fairly complex and deep draw and we have been experimenting with size of the blank, but we still get either rupture of the material in certain areas or other areas that don't pull out smooth. We are positioning the blank for best grain direction. The carbon level of the sheet being used is 0.009. Because this is a service part the volume being made is low and we don't have the option to go after any speciality extra deep drawing steel because we have to go to service centers. The supplier that originally made the part for us is out of business, and we don't know what his tool looked like, so for cost reasons we made a one stroke tool. The old supplier was most likely using a progressive tool to form the component. My question is : Would we have better luck with this deep draw if we were to use 304L sheet? Or is there another choice of material to use in the stainless arena ?

 

[unclesyd]

Have you look at drawing lubricants?

 

[EdStainless]

304 would draw much better. It has a lot of ductility.

But before you do that see if you can find Ultraform or HP versions of 409 out there. I know that you can find them in 439, a higher Cr grade of ferritic stainless. They have better formability.
Also make sure that you are doing this slowly with good lubrication.
The ferritics don't work harden much so if they begin to overload in one area it usually leads to rupture.

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