control arm material??

i am in the deal of makeing some custom control arms and strengthening the unibody rails, the real question is that what type of materials and what size should i use and what properties do they have like, are ductile? will i get good weld penetration? will it easily bend? or what is stronger? those are the real issues i have to face....

heres what i thought about for the control arms:

square tube: 2"x2" 1/4" wall structural square steel tube
grade: B
material: steel
outer diameter: 2"
specification: ASTM A500
style: structural
thickness: .250"
guage: 1/4 would this be adequite?

round tube: 2"OD x 1"ID x .5" wall 1/2 DOM carbon steel round steel tube
ID: 1.00"
MATERIAL: STEEL
OD: 2"
SPECIFICATION: ASTM A513
STYLE: D.O.M.
THICKNESS: 0.500"
GAUGE: 1/2 would carbon be bad?

1-3/4"OD X 1"ID .375" wall 3/8 GA. carbon steel round tube
ID: 1.000"
OD: 1-3/4"
SPECIFICATION: ASTM A513
STYLE: D.O.M.
THICKNESS: 0.375"
GUAGE: 3/8

would carbon steel round tube have good characteristics for welding when makeing control arms? is carbon steel tube like the ones stated above easily bend if dragged over some boulders? are their strengthes alright to built into control arm? thanks

and for the thought of reenforceing the unibody rails i was thinking of using a steel angle that would cover the outer and bottom side of the "rails" . i would use the bottom of the rail that would have the angle also welded to it for mounting control arms, skid plates. and crossmember/braces.
-this is what i was thinking of using


STEEL ANGLE: 6" x 4" x 3/8" THICK A36 STEEL ANGLE
FINISH: PLAIN
GRADE: A36
MATERIAL: STEEL
SPECIFICATION: ASTM A36
THICKNESS: 0.375" OR 3/8"

THATS WHAT I WAS THINKING OF USEING SO ANY HELPFULL COMMENTS WOULD BE GREATLY USEFUL, THANKS

:wierd:

(yes, it's a joke)

DR

norcal420 said:

:wierd:

(yes, it's a joke)

DR

Click to expand...

nice but wheres the toothpick and super glue approuch lol ha ha
ya but seriously i need some help about this here...........

This sounds like the question needs to be posted in Advanced Fabrication and Engineering

jeep_87_cherokee said:

heres what i thought about for the control arms:

square tube: 2"x2" 1/4" wall structural square steel tube

Click to expand...

I ran across some like this on an MJ (lowers only) in a junk yard this past weekend. They seem to have outlived the rest of the truck, but then again, so did the stock UCAs.

round tube: 2"OD x 1"ID x .5" wall 1/2 DOM carbon steel round steel tube
ID: 1.00"
MATERIAL: STEEL
OD: 2"
SPECIFICATION: ASTM A513
STYLE: D.O.M.
THICKNESS: 0.500"
GAUGE: 1/2 would carbon be bad?

I think that trying to get good penetration on that tube would be a bear and then joining it to what kind of joint ..tube insert ,, RE joint??



Holy Crap how much does that cost a foot..and then yoiu would have to have it shipped right...

Ive never even seen that size DOM on a site

Im a firm beliver in over kill on control arms but that might be even to much for me..

is what I would use

My lowers are 1.75x5/16" wall DOM. definitly stout as hell

control arm length should also be mentioned. if you're talking about near stock length (20 inches or less) you are thinking way overkill. if you're talking about 20-50 inches, I like your thinking, and any of the 3 will do great. I'm using 2x2 .250 square on my rear lower links and there is NO way I will ever bend them, it's generally cheaper than DOM too. Of those on your list, I would go between the square tube and the 1.75 .375 wall.

I'd go either 2x2x.25" HSS square or 2" O.D. .250 wall DOM for long arms.

1/4" thick material can easily be welded to with good penetration and don't worry about the "carbon steel" designation. Structural steel is also carbon steel. Generally any steel that is not some sort of steel alloy can be classified as carbon steel. As the carbon content increases so does the strength and hardness of the material but in general more carbon also makes a more brittle less ductile steel.

Typical structural steel has a yield strength of approximately 45 ksi while your good quality DOM is work hardened in it's production to give a little higher yield strength....about 55 ksi to 80ksi depending on they steel used.

I'd also go down in thickness on your reinforcements. I'd rather see you use 1/4" thick or 3/16" thick material but make it longer to better distribute the forces down the frame rail. The thing you have to remember when working with an XJ is how the entire body structure is designed to distribute forces through itself so well that all the materials used a very thin. The strength of the XJ is in it's design...not it's materials. By bolting on heavy rigid mounts to thin frame rails you create stress concentrations at the end of your super stiff mounts since they won't flex with the truck. It's better to go a little thinner and longer so your re-inforcements flex slightly with the vehicle which will reduce your stress concentrations.