Which is stronger:1.25" solid stock cold rolled mild or 1 7/8 diameter, 3/8" walled DOM mild steel as far as resistance to bending??? I need an answer fast if possible as I have today off, and need to make a steel run for link bar material for the front axle.

Thanks for any help out there from the metal gurus!!!!!!!

1 7/8 diameter, 3/8" walled DOM
:usa:

Thanks Blazerman! How significant is the difference (if you have the figures/chart/whatnot)?

The reason I ask is that on the front axle I have some significant clearance issues and the 1.25 solid stock would be a little easier to implement. Thanks again!

The I (Moment of Inertia) is larger (ie: more resistance to bending) for the larger diam. By how much, I'm not sure without some math :D

if you need a smaller diameter go with a smaller DOM in the same thickness. Frankly solid bar stock will NEVER be as strong for your application as tubing will be. It flexes entirely too much and has little structural rigidity like DOM tubing does.

Go tubing... hell go smaller and see if it breaks, but go tubing.
'

tubing would be better in bending, shear and tension, about 4 1/2 times better in bending, and about 45% percent better in tension, IF they are made of the same material, don't anyone know the tensile strength of cold rolled? I think DOM is around 60ksi, but not sure. That could make a difference, but I'll bet the tubing is still stronger.

chad

Cold Drawn Round's(solid)
astm a108 gr 1018
tensil p.s.i. =64k
yield point p.s.i.= 54k

astm a108 gr 1045
tensil p.s.i. =82k
yield point p.s.i.= 45k

Just in case anyone gives a fawk:flipoff2:

Now if you go with a stressproof like 4140 the tensil will be closer to 132,300 and will yield at 100k min

Thanks Scouttilac, but what do those numbers mean to a dumb layman like me; aka, so what are the numbers for solid stock 1.25 round vs. 1 7/8" DOM 3/8"walled mild vs. 1 7/8" 4140, and would 4140 have any brittleness issues for places like a link bar where rock contact is a definite concern with a 5000-pound rig (unfortunately.) Also, on the chromolly topic what are folks thoughts on just using say 1 3/4", .25"-walled 4140 or 4130? That would make inserting the 1.25" diameter weld-in inserts for these chromolly heims a cake-walk...

Originally posted by Scoutillac
Cold Drawn Round's(solid)
astm a108 gr 1018
tensil p.s.i. =64k
yield point p.s.i.= 54k

astm a108 gr 1045
tensil p.s.i. =82k
yield point p.s.i.= 45k

Just in case anyone gives a fawk:flipoff2:

Now if you go with a stressproof like 4140 the tensil will be closer to 132,300 and will yield at 100k min

I care! I went with 1.50" ETD Cold drawn shaft. Rocks!

I am ssuming both materials have the same elastic modulus. For bending stiffness, the difference between the two lies with the cross-sectional area moment of intertia terms. As I get it, the tubing has a moment of inertia of 0.496in^4, while the bar has a value of 0.119in^4. That roughly translates to the tubing being 4.1 times stiffer than the bar. (I haven't checked my work, did this one quick).

Hope this helps and isn't too late

See ya - :beer: :beer: :beer: :beer: