Need Help!- Milling 316L stainless steel!!!

[cemturkmen]

I ve problems with 316L. We are working for defense industry and stainless steel milling is what we have to deal always. Milling is easy. We can fit almost all the toleranses. But after we take the peice out from the machine there is always a bending. Altough we face mill both parts when we put the peice on a plate there is always a "u" shape. What can I do to solve the problem.

[JCVineyard]

If you are removing alot of material from the stock . You may want to roughout the part first, on all the milling operations. leaving enough for a finish pass on all the critical dimentions. After all the work pieces are roughed, then start with your finish passes.
this has worked for me in the past.

[cemturkmen]

Originally Posted by JCVineyard If you are removing alot of material from the stock . You may want to roughout the part first, on all the milling operations. leaving enough for a finish pass on all the critical dimentions. After all the work pieces are roughed, then start with your finish passes. this has worked for me in the past.

Thank you for the advise. 316L steel is tricky. Do you know wheather there is a heat thretment, quenching for the stainless steels?. Lots of force going on under 316L' I suppose . And one last thing, Tapping. Why it is so hard for small threaths. M4 and M5 tapping kills me. Is there any advise you can give for tapping and any tool brand?

[JCVineyard]

all stainless steel is tough to work with. usually more tough than hard. I don't know of any heat treatment that would make it any less of a pain to work with. as far as tapping it . see what the engineers require for % of thread. sometimes you can drill it a little oversize ( not much). to make it easier for the tap. You do need a good quality tap, there are several, OSG and Greenfield make a good tap, also a really good tapping fluid will help. I have had good luck with a product called (Molly Dee). good luck with all of your projects.

[cemturkmen]

Originally Posted by JCVineyard all stainless steel is tough to work with. usually more tough than hard. I don't know of any heat treatment that would make it any less of a pain to work with. as far as tapping it . see what the engineers require for % of thread. sometimes you can drill it a little oversize ( not much). to make it easier for the tap. You do need a good quality tap, there are several, OSG and Greenfield make a good tap, also a really good tapping fluid will help. I have had good luck with a product called (Molly Dee). good luck with all of your projects.

Thank you.

[Shane123]

i agree with JC, we usually drill the hole a couple thou oversized than normal callout to ease pressure on the tap. also, try anchor lube on the tap, seems to help

[cemturkmen]

Originally Posted by Shane123 i agree with JC, we usually drill the hole a couple thou oversized than normal callout to ease pressure on the tap. also, try anchor lube on the tap, seems to help

Thank you again.

[Delw]

Originally Posted by cemturkmen I ve problems with 316L. We are working for defense industry and stainless steel milling is what we have to deal always. Milling is easy. We can fit almost all the toleranses. But after we take the peice out from the machine there is always a bending. Altough we face mill both parts when we put the peice on a plate there is always a "u" shape. What can I do to solve the problem.

What defence industry are you working for? surely Its not the U.S. correct?




Delw

[cemturkmen]

Originally Posted by Delw What defence industry are you working for? surely Its not the U.S. correct? Delw

Turkish mostly but we manufactured some parts for DSCC (USA) and manufacturing parts for FMC (www.fnss.com) BAE systems have a share in FNSS.

[MMICKELS]

There is a paste for taping that I've always had good luck using on 316ss.Intercon Online - InterPurge, Baer Hardware, Jokisch Fluids, Tigrip, Hardy Non-Sparking Tools