Machining Thick A36 Plate

rokstarr999 · Oct 9, 2018

I have some pretty thick plates coming up and was thinking of roughing these out at water jet to save some time in the mill. Does anyone else do this? 2.75" is the thickest material I'll be working with. For profiling I was thinking of using a necked 5/8" EM. Any tips are appreciated..thank you.

Larry Dickman · Oct 9, 2018

I think you will find torch cutting them to be a whole lot cheaper.

Hcarte · Oct 9, 2018

I work with A36 Plate up to 9.00 inch every day. I would use a Sandvik 210 cutter the end mill is not going to like the burn scale. You can run a 210 cutter 700 SFM at 150 IMP all day long in that burn scale.

norb · Oct 9, 2018

I have the displeasure to work with this gummy steel in some of the machines I make. I would just buy it flame cut and most important STRESS RELIEVE!!!!!!!!! I have my heat treating house do a full aneal every time.

Larry Dickman · Oct 9, 2018

FWIW, torch cut A36 does NOT have a hard scale. Machines off like butter. (4130 is a different story)

rcoope · Oct 10, 2018

2.75 is getting pretty thick for waterjet so flame cut is probably the right answer but do get quotes.

Strostkovy · Oct 10, 2018

Be aware that the abrasive used in waterjet cutting can be a pain in the ass, or so I've heard.

Bobw · Oct 10, 2018

Looks like the plates are mostly to size. The pocket in the center would be a good
candidate if it actually went through..

And then you have that indent on the left. 8.425 x 3"? x 2.75 thick.. That's only 66 cubic inches.
Put 15hp to it, and that's out of there in a bit over 4 minutes. Or drop it out as a solid and have
a few nice chunks to make fixtures out of down the road.

If you could do it in house. Then probably not the worst idea, if you've got to ship it out and pay
for it, I don't think its worth it.

Mtndew · Oct 10, 2018

rokstarr999 said:
I have some pretty thick plates coming up and was thinking of roughing these out at water jet to save some time in the mill. Does anyone else do this? 2.75" is the thickest material I'll be working with. For profiling I was thinking of using a necked 5/8" EM. Any tips are appreciated..thank you.

If you have a waterjet in-house then ya, go for it. If you have to pay someone to do it outside of your shop, then just turn that material into chips.
A36 cuts like butter.

thesidetalker · Oct 10, 2018

Even if in house you are probably better off skipping waterjet.

One of my repeat jobs is 3" thick A588, shaped sort of like an "H". Material we order only comes in large plates, so need to waterjet something out of it.

First time I programmed the profile about .1" big, then finished on the mill. Took forever to cut on the waterjet so I changed it to just a rectangle, then milled all the material away. Much faster.

Like Bob says, maybe figure how many cubic inches you need to remove and plan accordingly.

87k psi, 2.75" A36 @ 50% speed gives me about 1.09 in/min... and slower yet in the corners.

DMF_TomB · Oct 10, 2018

if torch or plasma cut its the slag that is hard especially bigger pieces hanging at bottom of cut. i usually grind it off and then have no problems.

Mtndew · Oct 10, 2018

DMF_TomB said:
if torch or plasma cut its the slag that is hard especially bigger pieces hanging at bottom of cut. i usually grind it off and then have no problems.

It's A36.... You have no clue what you're talking about....again.

DMF_TomB · Oct 10, 2018

Mtndew said:
It's A36.... You have no clue what you're talking about....again.

A36 is structural steel roughly same as 1018 steel and i have made tens of thousands of tons of parts from A36 both by machining and welding A36. actually probably closer to thousands of tons of parts i have made out of A36 as bigger beams and plates and angle clips welded on ends can often can be over a ton
.
obviously i have made slag by torch and or plasma cutting A36. if slag is removed then i never had problems machining it. slag is hard and abrasive and whether on surface or in the steel it can be hard on cutting tools.
,
dont take a genius to figure out if you try to hand file slag off you can easy feel it dont file easy cause its hard and abrasive. i usually use a grinder rather than dull a hand file

Mtndew · Oct 10, 2018

DMF_TomB said:
A36 is structural steel roughly same as 1018 steel and i have made tens of thousands of tons of parts from A36 both by machining and welding A36. actually probably closer to thousands of tons of parts i have made out of A36 as bigger beams and plates and angle clips welded on ends can often can be over a ton
.
obviously i have made slag by torch and or plasma cutting A36. if slag is removed then i never had problems machining it. slag is hard and abrasive and whether on surface or in the steel it can be hard on cutting tools.
,
dont take a genius to figure out if you try to hand file slag off you can easy feel it dont file easy cause its hard and abrasive. i usually use a grinder rather than dull a hand file

Oh yeah, I forgot that you've worked with A36 and 1018 more than I have in the past 30 years.
Yes, that was sarcasm.

DMF_TomB · Oct 10, 2018

Mtndew said:
Oh yeah, I forgot that you've worked with A36 and 1018 more than I have in the past 30 years.
Yes, that was sarcasm.

its like when a apprentice or a engineer doesnt think slag can be hard and or abrasive. obviously not worked with A36 too much. whether on surface or deep in a steel plate slag can be hard and abrasive.
.
yes i have worked with hundreds if not thousands of tons of A36 over the last 40 years. i have worked on steel columns that were 5000 lbs for each column it dont take long to reach 1000 tons
.
obviously try hand filing slag off A36. dont take a genius to realize slag is hard and dulling the file

INDmachine · Oct 10, 2018

Never a problem for me here, we just get the stock to rough size then start hogging away. we do have 6" cutters with 0.500" depths of cut though. We are also using a large gantry mill (160"x80"x45")

DMF_TomB · Oct 10, 2018

INDmachine said:
Never a problem for me here, we just get the stock to rough size then start hogging away. we do have 6" cutters with 0.500" depths of cut though. We are also using a large gantry mill (160"x80"x45")

.
usually big thick roughing carbide inserts are fairly tough. but i have wasted 10 sets of carbide inserts trying to finish mill where there was slag only grain of rice size.
.
big slag you loose inserts you start to hear the thump thump thump of milling cutter with some inserts with broke off corners. can easily damage the cutter body if you let it go too long like that

rokstarr999 · Oct 10, 2018

Thanks for all the tips, I really appreciate it. Not gonna water jet. I'll either turn it into chips or drill some holes and rough it out with a band saw. I imagine the latter will take forever and I'll just turn it all into chips with an inserted cutter. Drill some holes in the corners so the cutter doesn't have to work so hard.

I have these to do to out of 3" x 6" A36 Haven't quite decided how to approach them yet. Mill off the back, toe clamp it from the top and do the front is what I'm thinking.

DMF_TomB · Oct 10, 2018

rokstarr999 said:
Thanks for all the tips, I really appreciate it. Not gonna water jet. I'll either turn it into chips or drill some holes and rough it out with a band saw. I imagine the latter will take forever and I'll just turn it all into chips with an inserted cutter. Drill some holes in the corners so the cutter doesn't have to work so hard.

I have these to do to out of 3" x 6" A36 Haven't quite decided how to approach them yet. Mill off the back, toe clamp it from the top and do the front is what I'm thinking.

if torch or plasma cut you got to be careful putting in a vise cause of rough uneven shape is harder to hold often its safer to mill the torch cut part smooth and straight so it goes in a vise better

Mtndew · Oct 10, 2018

DMF_TomB said:
its like when a apprentice or a engineer doesnt think slag can be hard and or abrasive. obviously not worked with A36 too much. whether on surface or deep in a steel plate slag can be hard and abrasive.
.
yes i have worked with hundreds if not thousands of tons of A36 over the last 40 years. i have worked on steel columns that were 5000 lbs for each column it dont take long to reach 1000 tons
.
obviously try hand filing slag off A36. dont take a genius to realize slag is hard and dulling the file

First of all,nobody here gives a flying fuck how many tons you've machine of any kind of material, I don't know why you feel the need to keep telling us that on a daily basis.
And secondly, what magical torch are you using where it hardens A36 material?

Try this now, take a piece of A36, heat it red fucking hot... see if it flame hardens.
It won't get hard, ever. Unless you add carbon to it.
Don't take a genius to realize that does it.

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