AR400 Plate

[Bggrnchvy]

If you are paying for new steel rust like that is pretty unacceptable. Some surface rust is fine but nothing that does not come off with a wire wheel is too much, especially pitting.

If he was buying it out of the scrap/cutoff pile then yah he gets what he gets.

That. I would fire a vendor in a heartbeat if they tried to deliver that plate as new.

I've got some scrap plate that sat in the mud next to my shipping container for 5 years while I was building my shop with less pitting and I don't want to use it

 

[AKnate]

Hiw about A514 aka T1?

 

[Lbhsbz]

Thats bullshit.

If you're paying for new material, it should look new. I hauled some chunks of plate out of my neighbors backyard that had been there outside in the elements for 30+ years and they're in better shape than that. If you paid more than scrap value for that you got fucked.

 

[desertPOS]

Little bit of a shitshow returning it, but they took it back - in the future I know that if I order plate from that department I need to physically find the specific piece of metal I want, make sure the mfg info is printed on it so I know what it is, and have them cut out of that. Otherwise the actual company has been great, and I've been getting all my metal from them for years - stopped by today to pick up more odds and ends

Anyway, before going this direction I searched here, Pirate, and general web search for everything 'AR400.' Impression I got was that it's more resilient, obviously, but being tougher/less prone to denting or scraping made it slide really well. Which is good. Comparable to UHMW possibly, without being a wear item that needs regular replacing. Tougher to work with. Some people say you can drill it with a masonry bit, others say no way. Some people say you can cut it with an annular cutter, others say you can't (although at least a couple things I read were people talking about whether you could/couldn't drill it with a mag drill - I'm assuming they were talking about annular cutters, but no specific mention of that - so vague information).

So here's where I'm at: I went to supplier #2 and went through their yard, and found a pretty clean piece of AR400 that had the mfg printed designation of 'AR400' on it. Had a 3x4 cut from that, took it home and cleaned it up. Looks better in person than in pics. It's clean:

Not sure what to think about this:

I can drill it, and I can countersink it - which is completely opposite of everything I've read about this stuff. I don't know how many discussions people chime in on that have maybe worked with AR500 or grades of Hardox wear plate and just lump that all together as general AR plate when they're discussing this stuff? Or maybe what I got was mislabeled or quality control is in the shitter, or ? Without a hardness tester I don't really have any other way of verifying what this is. Odd though that two pieces of plate from two different yards that are supposed to be AR400, and I can drill both

It's definitely no mild steel though - that's apparent. Automatic center punch on this vs. mild steel is a much shallower punch mark, much harder to cut, and drilling dry sounds like the bits breaking continually. I can cut it with a cutoff disc, but it's slow going. Very inconsistent as well - disc will be cutting slow and steady, and then get to what feels like a harder spot where it's hardly cutting at all and feels like it's binding up and trying to climb out of the cut. I was using .030 cutting discs and they were deflecting real bad and had a hard time maintaining a straight cut, whereas mild steel they'll cut like butter nice and straight. I'm going to pick up some thicker discs later and see if that helps, although I'm sure it'll slow down cut speed quite a bit. I could also just plasma cut it, but even if it's slow I'd rather just have a clean straight cut. Or maybe I need to up my plasma cutting game...



If this is indeed AR400, it's surprisingly not too bad to work with so far. Countersink started chattering pretty good on the drill press, so later I'm going to try turning it a lot slower on the mill and hopefully the lower speed and more consistent pressure clean that up a bit

 

[white-rhino]

AR400 is not impossible to work with. You just described it. Center punch is not as deep. Drill squeals. Cutoff wheel has to work harder. Now go to AR500 and it will get worse.
Hardox has been mentioned a couple times. That is just the trade name of SSAB's AR plate. Nothing special about it and no different than AR plate made by Nucor and Cleveland Cliffs.

 

[wrath]

All the AR plate I've bought that comes from places like Alro (reseller based in Michigan but have places out of state) has what it is printed on the sheet and who made it. The AR plate I've gotten from mom and pop shops for less than half the price just have it squiggled on by hand. I'm pretty sure that stuff comes from China. I use it for backstops.

The expensive AR plate, in my experience, is very consistent versus the cheaper plate. So when I'm sitting there contemplating my life choices waiting on the cutoff wheel there is no surprises. To me, it reminds me of cutting stainless. Slow, steady, boring.

I've only used AR200, AR400, AR500, some weird heavily oiled European AR550 once, and AR600. AR200 and AR400 are pretty easy to work with. Quality cutoff wheels, flap discs, grinding wheels, and cobalt drill bits make it fine. AR500 and up is about the only time I use the plasma anymore. The AR600 cost me a lot of bits to make a new edge for an end loader used at a dairy farm.

My favorite is AR400. If it were a little cheaper I'd use it for a lot more projects. You can literally half the thickness in a lot of applications versus mild steel.

 

[ihpartsjeff]

When I built Hideous I bought 3/16" thick AR400 from a local metal supply. It was rusty like what you got so I had to spend some time cleaning it up with my sandblaster. Yes it was hard to drill and countersink but not impossible. Has worked and held up real well for a 7000 pound rig.

 

[SomeGuyFromOlympia]

they took it back after you cut and drilled it?
they knew they did you wrong

 

[AKnate]

So 1/8" AR400 is equal to 1/4" mild steel?
1/4" AR400 is over 2x the cost of mild steel. Around $1500 vs 700.
Didn't price 1/8" though.

 

[LScout800]

So 1/8" AR400 is equal to 1/4" mild steel?
1/4" AR400 is over 2x the cost of mild steel. Around $1500 vs 700.
Didn't price 1/8" though.

A36 is typically what the standard mild steel plate is. Here is the properties of AR400 plate compared to A36 plate on send cut sends property tables. The numbers seem pretty consistent with what I see else where.

AR400 Steel - SendCutSend

SendCutSend offers several materials for steel laser cutting including AR400 steel, which has excellent abrasion & impact resistance.

sendcutsend.com

https://sendcutsend.com/materials/mild-steel/

The AR400 is way harder than the A36, and a bit tougher, and has lower fatigue strength. This means it won't scratch easily but will crack if you bend it too sharp, and it is pretty hard to bend. It also is twice as expensive according to building an identical part between the two steels on their site.

Only experience I have had with it is building some trash tuck bin stuff with it. I only ever cut it with a torch and ground it a little for welding, never had to drill or bend it so have no idea how it deals with that.

You can't really say one is twice as good as the other so you can use 1/8" material instead of 1/4" for the same application. Different materials have different applications and uses.

 

[Landslide]

Ordered a some3/16" AR 400 for some belly skids - local steel yard - went to pick it up a couple days later once they got it cut and they had a pretty rusty piece of plate waiting for me. When I asked if they had anything cleaner, guy gave me a bunch of shit like I was being a primadonna or something. We ended up walking their rems area, which is all they said they had in 3/16, and they didn't have anything cleaner.

Is what it is, I can make it work. Got a few hours now into cleaning all the rust off with stripper pad and 7" sanding discs - oxidized layers definitely seemed harder to remove than regular plate. Plasma'd out the first piece I needed , then on to the second piece, which required some holes drilled. I haven't worked with this stuff before, and have read mixed reviews on whether annular cutter will work or not. Chucked a 15/16" carbide copperhead into the mag drill and was happy to see it go through it like butter - douched the cutter up with some Rotagel and didn't seem any different than mild steel.

Decided to see what all I could drill it with, since I'm still planning how I'm actually going to mount it. Low and behold, a well-used 1/8" generic drill bit in a cordless drill went through it without any fuss. Maybe seemed a little harder than if it were just mild, but not sure. Not in line with what I've read about AR400 - not even close. Ran a couple steps of a Harbor Freight step drill through it and that worked as well. Used a cutoff disc to lop a corner off, then beveled it with a worn out flap disc. Other than the oxidation layer seeming much harder to remove, I'm not seeing much difference between this and 3/16 mild steel.

After what I've read about this stuff, seems pretty clear it's the wrong material, but before I call up Mr. Sunshine over at the steel yard I thought I'd see what opinions I got here. Anyone find it easier to work with than they thought? My impression was you might get lucky with masonry bits, and mixed reviews on whether annular cutter would work or not, but I also don't know if people are talking about AR plate in general when they say that, or specific to 400 vs. 500 vs. whatever else. In retrospect, I recall seeing a piece of clearly branded Hardox in their rems area, and wondering if they even keep track of what grade is what or if it's all just mixed together out there

Pics!

Supplier sold you a sheet of steel left outside for years.

AR500 plate is heavier steel than A36 mild steel.

I got a buddy who cuts out steel targets with it and I have several of those including a resettable target tree. Everything is cut out on a CNC plasma including the holes for the chain swinging ones.

That’s all I can add.

 

[srf]

So 1/8" AR400 is equal to 1/4" mild steel?
1/4" AR400 is over 2x the cost of mild steel. Around $1500 vs 700.
Didn't price 1/8" though.

For wear life, probably I find it's about 2-3x tougher.

We use some AR400 in our shot blasters. They'll punch a hole through 3/8" A36 in a few weeks, AR400 will last a month or two.

 

[desertPOS]

AR400 is not impossible to work with. You just described it. Center punch is not as deep. Drill squeals. Cutoff wheel has to work harder. Now go to AR500 and it will get worse.
Hardox has been mentioned a couple times. That is just the trade name of SSAB's AR plate. Nothing special about it and no different than AR plate made by Nucor and Cleveland Cliffs.

AR500 seems like a big leap up in the hardness department from what I've seen/read. Hardox is a brand, but thought I saw somewhere that their stuff wasn't as workable, wasn't as weldable. I'm just surprised how easy it seems to work with compared to what I thought going into this. I even talked to a buddy of mine when I got the first plate, and he was saying he wanted to know where I got my drill bits, since he's never had good luck drilling it. He's worked with AR plate a decent amount over the years. Makes me think that, like a lot of stuff I read beforehand, people maybe just lump their experience working with harder AR plate into discussions about softer AR plate?

Here's a cool video of a guy drilling and countersinking AR500 that I watched just before buying this stuff:


For the sake of adding some tech, my plan of attack was:

1) test drill it with mag drill and carbide annular cutter and see if that works. 7/8 or 15/16" holes, so that I can then weld mild steel on as a backer, then drill/countersink that(even if masonry bit works, doesn't do much good if you can't countersink it on a belly skid plate)

2) same as 1, but if annular cutters wouldn't work, plasma the holes and weld a backer

3) mark the spots I want to drill, and heat those specific little spots with a torch to cherry red and 'spot anneal' it so I can drill and countersink

they took it back after you cut and drilled it?
they knew they did you wrong

They didn't even ask to see it. I called the guy I originally ordered from and he said bring it back and we'll see what we can do to get you something cleaner. Told him I'd be there in 15 minutes. Got there 15 minutes later and, "Oh he's out to lunch." Fucker. So now I'm talking to the guy who always seems to have an attitude - figured instead of telling him the problem, I'd just let him come to his own conclusion. Told him I'm having trouble drilling it. "You can't drill that stuff dude, you don't know what you're doing." So I asked him why can't I drill it? "That's abrasion resistant plate, you can't drill it - it's too hard." So then I explained that I not only can I drill it, but I'm drilling it with a cordless drill, and I'd like a refund. Guy #2 and then guy #3 chimed in, so it was a nice long back-and-forth with three people, two of which are in their offices.

Anyway, goes to show that even the guys selling it are saying it can't be drilled, when obviously, that's not correct

Anyway

 

[desertPOS]

When I built Hideous I bought 3/16" thick AR400 from a local metal supply. It was rusty like what you got so I had to spend some time cleaning it up with my sandblaster. Yes it was hard to drill and countersink but not impossible. Has worked and held up real well for a 7000 pound rig.

That's a badass rig - what's the belly height on that thing?

 

[Dethmachinefab]

It can absolutely be drilled and countersunk. It's not drill bit hard. Keep a good chip and the bit cool and have at it.

Most people can't properly drill mild steel, so anything harder is impossible going at it full speed on a hand drill with a 1/2" harbor freight drill bit.

 

[desertPOS]

Luckily I'm a glutton for drilling some holes Debated welding the center piece in originally, but since it's drillable it'll be a lot easier to get access under the rig later by just unbolting a panel as opposed to removing the entire skid plate, so all ar panels will be bolted in. Although, if need to remove the whole skidplate, the whole thing can be removed as one piece, and can drop it down by pivoting on the rearmost two bolts. Should make it easier to remove/install

Speaking of harbor freight step bits - black ones are great. And hell no, I never use any oil with those things. They're good for a few hundred holes, looks like they work with ar plate as well

1" countersink - with this I definitely did use oil, and turning around 100 rpm. Mechanical pressure as opposed to hand pressure like drill press - maintain enough pressure to keep it cutting and try to keep from getting a wavy finish

 

[AKnate]

Luckily I'm a glutton for drilling some holes Debated welding the center piece in originally, but since it's drillable it'll be a lot easier to get access under the rig later by just unbolting a panel as opposed to removing the entire skid plate, so all ar panels will be bolted in. Although, if need to remove the whole skidplate, the whole thing can be removed as one piece, and can drop it down by pivoting on the rearmost two bolts. Should make it easier to remove/install

Speaking of harbor freight step bits - black ones are great. And hell no, I never use any oil with those things. They're good for a few hundred holes, looks like they work with ar plate as well

1" countersink - with this I definitely did use oil, and turning around 100 rpm. Mechanical pressure as opposed to hand pressure like drill press - maintain enough pressure to keep it cutting and try to keep from getting a wavy finish

I have a couple i burned up that I took 30 seconds and sharpened for S&Gs as a last ditch before tossing. Worked fairly well

 

[Johann]

Can you spark test AR400? I know I can tell the difference between 1050 and mild by the sparks cast when I have a question.

Also, can it come in an annealed state?

We got some 4130 sheet for a project that turned out the guy ordered it in a hardened state. Pain in the ass to work and cracked when edge rolled. The place he got it from offers it in Hard, Half hard and annealed. I just chucked it in my forge and let it cool slowly and it behaved well enough. Work hardened pretty fast though

 

[ihpartsjeff]

That's a badass rig - what's the belly height on that thing?

Thanks! Great question as I have never measured it. Will try and get a measurement on it tonight.

EDIT - Belly sits at 20 inches.

 

[AlxJ64]

Hiw about A514 aka T1?

Machining and drilling it is easier than AR400 and 500, but welding takes a bit more skills. Especially a butt weld.

 

[SomeGuy]

Luckily I'm a glutton for drilling some holes Debated welding the center piece in originally, but since it's drillable it'll be a lot easier to get access under the rig later by just unbolting a panel as opposed to removing the entire skid plate, so all ar panels will be bolted in. Although, if need to remove the whole skidplate, the whole thing can be removed as one piece, and can drop it down by pivoting on the rearmost two bolts. Should make it easier to remove/install


Speaking of harbor freight step bits - black ones are great. And hell no, I never use any oil with those things. They're good for a few hundred holes, looks like they work with ar plate as well


1" countersink - with this I definitely did use oil, and turning around 100 rpm. Mechanical pressure as opposed to hand pressure like drill press - maintain enough pressure to keep it cutting and try to keep from getting a wavy finish

Get some single flute countersinks like this:

They work WAY better on steel than those lousy little grindy things as they cut an actual spiral chip.