18-8 stainless

[AMCNitro]

Does anybody have any experience with this stainless?  How is the machinability?  What does it compare to?  Ive machined 15-5, 17-4,13-8, 304,303,420, but never 18-8.

[mkd]

a bit gummier, maybe a bit tougher... but it's been about 20years since i've touched the stuff.

If you are doing the other alloys, you should be fine.

[MIL-TFP-41]

my bad...see post below....

[Sticky]

18-8 is basically 304.

 

18-8 is actually not as defined and refined as 304, but in a lot of instances 18-8 is actually 304, but named 18-8 to suit a certain industry.

 

It is gummy material, the key to good tool life is very sharp tools, fairly high sfm (400-600sfm), and light chip loads. It doesn't respond well to low sfm high chip loads like 17-4. Of course good rigidity, and high quality coolant with a rich mixture is important.

[Mike@Lustre]

Have to agree with Sticky , when comparing 304l to 18/8 the base materials are pretty much the same .

[AMCNitro]

Thanks for the replies!

[Newbeeee™]

We're running a couple of thousand parts at the moment in 316.

For roughing, we tried a 12mm dia tool with a 0.5mm rad on the bottom thinking it would last longer because it's stronger, but nope, square bottom geo lasted nearly twice the parts.

Also, we're running coolant at 10%.

We found that the worse thing you can do with this is overspeed. It will take a big cut (rigidity dependent) but it's best to find the sweetspot and back off 10% and tool life rapidly increases.

[Tim Johnson]

I would rather run 316 than 304 any day of the week especially these days when 304 and 304L (316 and 316L also) are the same material.

[Sticky]

I would rather run 316 than 304 any day of the week especially these days when 304 and 304L (316 and 316L also) are the same material.

 

Agreed, I'd rather run 13-8, 15-5, or 17-4 more than 304.

[AMCNitro]

I would rather run 316 than 304 any day of the week especially these days when 304 and 304L (316 and 316L also) are the same material.

 

 

Agreed, I'd rather run 13-8, 15-5, or 17-4 more than 304.

 Oh, absolutely!  I rather run heat treated 17-4 or 15-5 than any other stainless.