Machining A36 plate

[alloy]

I'm doing some 1/4" thick plates for a customer and am profiling them with a 5/8" rougher .005 over then finishing them with a 1/2" 6 flute carbide end mill. Both cutters are using flood coolant.

This looks like it will be an ongoing job for me. The A36 seems pretty hard on the roughers. I've not machined A36 before and am considering getting a 5/8" carbide insert end mill. I've looked up info on machining A36 and it's all over the place. No clear recommendation.

So stick with the roughers or go carbide?

 

[GL]

I can’t speak to your question regarding roughers or inserts, however, because A36 is a mechanical specification as opposed to a chemical specification, we found we had better luck with 1020 for machining and bending consistency. I do find high positive “aluminum” inserts give me better finishes on mild steel when turning but I’m not pushing things hard, I assume that would transfer to milling operations. Will be interesting to see what others have to say..

 

[alloy]

A36 is what is available to me somewhat locally. 1018 is a 120 mile round trip. The A36 is acceptable to the customer.

I'm running the parts now. It eats hss coated roughers for lunch.

 

[dkemppai]

I seem to recall it's pretty gummy stuff. Not sure why it's worse than other low carbon steel. I always fight getting a good finish on it. It seems like it really likes to fall, ruining the surface finish.

Turning it, I did find a lightly wetting the part with firefly lamp oil seemed to make a big difference. No idea why that helped, and tried it out of frustration as the bottle was handy. (Bought the bottle as something to wring gauge blocks together with).

Small carbide end mills seem to do ok in it too.

Playing with feeds and speeds might yield a better life from the tooling. Of course that advice tends to hold in general!

 

[ptross]

Not sure why it's worse than other low carbon steel
it is a different chemical makeup. .
Not sure which elements contribute to its irregular machinability, but A-36 often has high manganese content.
Any metallurgists present?

 

[alloy]

Im running a coated 4 flute hss rougher at 12 ipm and 800 rpm. So far that's yealded the best tool life.

 

[WobblyHand]

Has the A36 been descaled before machining? I found the scale reduced the tool life. I made a monitor stand, out of some 3/8" thick A36 for the upright and 1.25" thick A36 for the base. Took a bit, on my small mill to clean it all up and get things square. As I recall I used a rougher on the thicker piece's edges. The flame cut was not kind to my rougher. Didn't ruin it, but it is duller. HSS rougher. I used Tap Magic cutting fluid. Used a face mill to clean up the large surfaces, an AliExpress special, but it made a nice finish.

 

[toprecyler]

Have you tried slowing RPMs down on Roughing end mill?

Maybe around 5-600 RPM, and 4-5 IPM?


Sent from my iPhone using Tapatalk

 

[alloy]

No have not done any surface prep. Not what the customer wants.

Yes I've tried slowing it down, speeding it up, everything in between. That's why I'm thinking of going inserted carbide. The rougher chips look good, so does the roughing cut. After the rougher I finishing with a 6 flute solid carbide end mill for the correct size.

 

[Alexander McGilton]

If you see yourself making more in the future and in modesty higher qty's. Get the carbide roughing end mills. With the exception of special shapes and low speed operations like tapping and reaming. HSS hardly touches my work.

Indelible end mils are more suseptible to vibration and chatter. When the speeds and feeds aren't just right for them. No factual reference, just an observation. After all they are made a little dull, unlike solid carbide endmills.