Machining 321 Stainless Steel
Machining 321 Stainless Steel
(OP)
Drilling a hole pattern in 2" thick 321 Stainless and tools aren't lasting. Carbide reamers getting chewed as well as drill bits. Any materials, speeds or feeds to recommend? High speed steel the only one going past one hole so far. Suggestions? Thanks.





RE: Machining 321 Stainless Steel
RE: Machining 321 Stainless Steel
RE: Machining 321 Stainless Steel
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RE: Machining 321 Stainless Steel
We were attempting to make fiber spinnerettes from 321 SS where we encountered some problems with tool wear. This was a serious problem as were attempting to drill and flat bottom 640 1/8" holes 3/4" deep. The problem was random as some material machined without any problems. It ended up that the problem blanks were from one heat. Checking the MTR and laboratory analysis revealed the Ti be at the max on MTR and slightly above by actual analysis. Metallurgical examination reveal inclusion like areas of Titanium Nitride. This was what was tearing our tooling up.
Several years later we had the same problem with 430 Ti SS in the same process.
Blanks for this process were cut from annealed plate.
You might want to check your MTR's for Ti on the high side.
RE: Machining 321 Stainless Steel
RE: Machining 321 Stainless Steel
RE: Machining 321 Stainless Steel
If the only issue here is to optimize tool life and hole quality look for a cutting oil 150+ Visa with Cl and active S
A.R. "Andy" Nelson
Engineering Consultant
anelson@arnengineering.com
RE: Machining 321 Stainless Steel
Vibration will kill carbide most of the time. See if you have the part / tools securely set-up and can you use drill bushings or guides?
Also, speed / feed rates can be guessed at quite reliably by checking the following web site:
http://www.multi-drill.com/drill-speed-chart.htm
Reaming is approximately 2/3 of the drill speed on RPM. Feed is dependent on material, cut amount, etc.
Good luck!
Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com
V8013-R
RE: Machining 321 Stainless Steel
Please click on this link thread404-230305: Self-stopping drill depth? and see if you can assist the OP with his problem.
Read the whole thread to understand exactly what his problem is.
thanks
RE: Machining 321 Stainless Steel
RE: Machining 321 Stainless Steel
This speed and feed seemed a little agressive so we slowed it down to 8.8 M/min (29 SFM) and 0.016mm/Rev (.0006"/rev) =23mm/min (.91"/min) Hole count went up by 29 %
Slower & HSCO, seems to be the way.