Welding AR500 Steel Plates

[groovatron]

Thanks for the link!

Looks like it was recommending a post-weld heat treat if one were inclined to weld at all, due to possible damage to the "heat affected zone".

Yes sir.

And FTR, I didn't mean to sound like a know-it-all in my earlier posts. I may know a decent ammount about welding, but I know very little about steel targets and even shooting steel targets for that matter. I know that heat treated steel "can" be welded, but it is now clear to me that it would be a poor decision for this paticular application. So anyway, thanks for bringing this subject to my attention. I learned something as well as gained a bit of interest in perhaps constructing by own target

 

[Rookie]

I have no experience with AR500, but I built some target holders for the local gun range. 1/2 mild steel (mounted at 30 degrees) will stand up fine to pistol caliber rounds. .223 will put some nice dents in it, but it won't penetrate.

Heat treatment isn't that difficult. Get the steel a dark cherry and quench it in motor oil. Tempering - put the steel in a 400 degree oven for an hour.

 

[lawrra]

AR500 is some hard steel. In comparison, the impact beams in car doors have a lower tensile strength (amount of force needed to break). With the original hardness of the AR500 being 450+ Brinell, a few quick beads shouldn't soften it much.

For a little background: my job is to heat treat steel bar and tube. After heating steel to its austenizing temperature and quenching, several grades of steel will be near the hardness of AR500, but they are brittle. Tempering relieves stress in the steel, provides better mechanical properties, and lowers the hardness. AR500 can withstand the beating of bullets because of its chemistry giving it a high tensile strength and yield.

As long as you don't douse the steel in water after welding and keep the HAZ to a minimum, you will only temper a small area that will unlikely affect the hardness all the way through.

If the steel is dark red in color around the welds for a few seconds after stopping you should be fine. If it's bright red or orange that's way too hot.

Welding on the front of the target would not be a good idea.

 

[esrice]

Yes sir.

And FTR, I didn't mean to sound like a know-it-all in my earlier posts.

I never took it that way. I appreciate your comments, as it helped to bring this topic to the top to be discussed further.

I also appreciate everyone's input so far-- lots of good info here!

 

[lawrra]

Alright, I had a discussion with a co-worker. Welding AR500 would normalize it. You're looking at roughly a 50 Brinell loss in the HAZ. That's pretty good considering how hard the steel is treated to. To minimize soft spots to critical areas of the target, make your brackets to extend to the edge of the target. A quarter inch short of each edge should work well (it wouldn't be neccessary to weld at the top). Keeping the welds on rear edges with light penetration will be sufficient since the steel is likely already softer from the cutting method used (plasma or laser), and your focus will be to hit the center of the target. Air cool after welding ONLY. If you would like a drawing of the mounting assembly I have in mind, let me know.

 

[1946]

Can anyone tell me what the ksi is for AR500 steel? The reason I'm curious is because I'm using a 2ft x 2ft x 3/8 in. piece of boiler plate that according to the steel yard I purchased it from, has a ksi of 60 to 65.
In looking around the web, I see that A500 steel has a ksi of 46, which is milder than what I'm using for a back stop.
Is the A500 pretty much the same as the Ar500?
I've yet to use high power on it, but hot 44 mag on down does not dent or dimple the sheet that I mentioned in my second sentence.

 

[lovemywoods]

Can anyone tell me what the ksi is for AR500 steel? The reason I'm curious is because I'm using a 2ft x 2ft x 3/8 in. piece of boiler plate that according to the steel yard I purchased it from, has a ksi of 60 to 65.
In looking around the web, I see that A500 steel has a ksi of 46, which is milder than what I'm using for a back stop.
Is the A500 pretty much the same as the Ar500?
I've yet to use high power on it, but hot 44 mag on down does not dent or dimple the sheet that I mentioned in my second sentence.

A500 is a very different steel series than the abrasion resistant AR500 steels.

This site:
AR500 / AR500F Alloy & Abrasion Resistant Steel Plate - Chapel Steel

Lists a specification for AR500 steel as 247 ksi Tensile and 187 ksi Yield.


This site has the specification considerably higher:
Major Metal Service – Gillette Wyoming Steel Plate Fabrication Flame Cut Steel

 

[1946]

Thanks lovemywoods. I appreciate the input and the site info.
I guess I won't bother trying high power rifle on my plate. Sounds like it would just make swiss cheese out of it.