Need recommendations for working with AR400 plate

[jackal]

I have a customer that has a large wood chipper. The feed rolls on each side have these worn gripper strips that need replacing.
I'm guessing the material is some type of AR plate ( guessing AR400). These straps are 15-1/2" long. They are 1/4 " thick, and stick out 5/8". It looks like metal slats sticking out, and they are skip welded with (probably 7018).
I have a sheetmetal shop quoting the price for using a water jet to cut these plates out.
Could these be sheared from 1/4" AR 400 plate?

Across the top they have a chisel edge to help grab the wooden limbs. My thoughts are that I can use an old carbide end mill to put this edge, and finish with a hand grinder.

I'll try to post some pics.
Having never worked with AR plate, any advice or help is appreciated.

Thanks,
Jack

 

[jackal]

20211020-112233 — ImgBB

20211020-112308 — ImgBB

20211020-112237 — ImgBB

One of the workers ccommented that these fins look like large metal rulers.

 

[boslab]

I use plasma myself, good enough finish
Mark

 

[jackal]

I use plasma myself, good enough finish
Mark

With plasma, does the edge become brittle or hard??
Also, does it warp the material?

 

[52 Ford]

The only AR plate that I've personally worked with AR plate for steel rifle targets.

I'd cut the pieces with O/A or plasma, then rough the angled edge in with an endmill if possible, otherwise a 9" grinder aught to make quick work of it. It is just 1/4" after all. AR400 is 40 rockwell , right?

Sent by freight using Tapatalk.

 

[jackal]

The only AR plate that I've personally worked with AR plate for steel rifle targets.

I'd cut the pieces with O/A or plasma, then rough the angled edge in with an endmill if possible, otherwise a 9" grinder aught to make quick work of it. It is just 1/4" after all. AR400 is 40 rockwell , right?

Sent by freight using Tapatalk.

Thanks for that info.
I've never been around it, and most of my locals haven't used it much.
Mostly they made wear plates for construction equipment.
Or, like you said targets.
Thanks again for the info.

 

[52 Ford]

Heres something talking about welding AR400.
AR400 Welding & Machining | Associated Steel Corporation



Sent by telegraph using Tap.... Tap-Tap. Tap. Tap.

 

[jackal]

Heres something talking about welding AR400.
AR400 Welding & Machining | Associated Steel Corporation



Sent by telegraph using Tap.... Tap-Tap. Tap. Tap.

Thanks for all of your help and info.
I appreciate it.

 

[boslab]

I use plasma myself, good enough finish
Mark

There’s a HAZ, fairly unavoidable unless you go water jet ( an option if available), it’s never been a problem with the Hardox 600 I’ve used as lifters in drum mixers, actually hardens the wear zone a little, wouldn’t think that grip cleats would need milling myself and hard wear edge is an advantage, not used AR plate only SSABs hardox range, tough old stuff
Mark

 

[jackal]

There’s a HAZ, fairly unavoidable unless you go water jet ( an option if available), it’s never been a problem with the Hardox 600 I’ve used as lifters in drum mixers, actually hardens the wear zone a little, wouldn’t think that grip cleats would need milling myself and hard wear edge is an advantage, not used AR plate only SSABs hardox range, tough old stuff
Mark

Thanks for that info. The only reason these need to be milled is because the originals have a "rooftop" chisel edge on them, and they want the new ones to be the same. I might be able to do this with a cup grinding wheel on a 7" grinder.

 

[Rob F.]

I have a sheetmetal shop quoting the price for using a water jet to cut these plates out.
Could these be sheared from 1/4" AR 400 plate?

Shearing the 5/8 strips will probably twist them a little. It should be easy to un twist by clampinng one end in a vise and large crescent wrench on the other. Or pay more for plasma or water jet etc. Choose your trade off.

 

[jackal]

Shearing the 5/8 strips will probably twist them a little. It should be easy to un twist by clampinng one end in a vise and large crescent wrench on the other. Or pay more for plasma or water jet etc. Choose your trade off.

Thanks Rob.
It might be easier to shear and straighten. I'll see what he quotes with the water.

 

[52 Ford]

Thanks for that info. The only reason these need to be milled is because the originals have a "rooftop" chisel edge on them, and they want the new ones to be the same. I might be able to do this with a cup grinding wheel on a 7" grinder.

Yep. Cup wheel on a big grinder. I forgot to say this earlier... see if you can rent one of those O/A or plasma torch guide rail auto feed things and use that to rough it in angles. You set it up on the plate, light the torch, then it moves the torch for you like power feed on a lathe.

Edit: Google "Oxy-fuel track burner". For some reason the word "track" had escaped my mind when I was first trying to remember what they're called. LOL

It's a variable speed motorized carriage with a torch mount and a guide rail.

Sent by telegraph using - .- .--. .- - .- .-.. -.-

 

[jackal]

Yep. Cup wheel on a big grinder. I forgot to say this earlier... see if you can rent one of those O/A or plasma torch guide rail auto feed things and use that to rough it in angles. You set it up on the plate, light the torch, then it moves the torch for you like power feed on a lathe.

Edit: Google "Oxy-fuel track burner". For some reason the word "track" had escaped my mind when I was first trying to remember what they're called. LOL

It's a variable speed motorized carriage with a torch mount and a guide rail.

Sent by telegraph using - .- .--. .- - .- .-.. -.-

We used a track torch at the last place I worked.
I might be able to drag my plasma cutter along some angle iron and get a rough angle.

 

[52 Ford]

We used a track torch at the last place I worked.
I might be able to drag my plasma cutter along some angle iron and get a rough angle.

Worth a shot. Maybe try it in mild steel first. If it cuts that, it aught to cut AR plate just the same.

Sent by telegraph using - .- .--. .- - .- .-.. -.-

 

[gbent]

I don't know what you have for a shear, but I wouldn't try AR400 in mine. 400 Brinell hardness, harder than 4340 pht steel. O/A, plasma, or water jet.

 

[jackal]

I don't know what you have for a shear, but I wouldn't try AR400 in mine. 400 Brinell hardness, harder than 4340 pht steel. O/A, plasma, or water jet.

Thanks for that info. Someone the guys that have said that work for a company, so it's not their equipment.
I may go with a couple of strips using my plasma. If it isn't too warped or straightens ok, I'll do that.
Otherwise, water jet.

Thanks for the info.

 

[Imechura]

1/4" AR plate, go with plasma. Anything over 50 amps is more than enough, 40 amps would be pushing it.

You don't need a track burner for this. Just get a piece of straight 3/8" CRS long enough to use as a straight edge and clamp it to the plate with vice grips at both ends and mind the offset for the tip radius. Use a drag tip so you can drag cut to keep a consistent height because that's what will determine if your edge is uniform width.

You need to cut it in a single pass without stopping if you want the best results. Do that, and keep the torch somewhat at the same angle and it will come out how you need it.

Try the setup on some 1/4" hot roll scrap a few times to get the hang of it first.

You will not warp 1/4 steel cutting with plasma. Plasma doesn't put nearly the amount of heat into the metal as oxyfuel cutting or welding does and as soon as the plasma pierces through its not technically in contact with the metal anymore in that same location. Its hotter but the arc is moving too fast for the heat to be absorbed enough to warp the metal.