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HREW vs. DOM dent resistance

cracker

cracker

NAXJA Forum User
Location
La Mierda
So I have heard / read different opinions on this. Can please someone clear this up?
 
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Capt. Nemo said:
Same ones who sold you the kingpins???
Click to expand...

Nope

There is another list of peeps. ;)

BrettM said:
get the specs for the steel from your supplier, if the tensile strength is higher on the DOM (which it should be!) then it is stronger for denting also.
Click to expand...

I think my mis understanding is the true definition of tensile strength. I understand structurally the DOM is stronger and what not (chromoly even more). I also know if I build a structure out of aluminum it can be strong as hell but alumimun can dent so much more easily.

For example (my real world experience with the material), I see bicycles made out of chromoly all day long having front end impacts. All the chromoly frames seem to bend at the head tube quite easily but the aluminum frames (visually) holds up and the fork folds in a heart beat. But as far as denting, the aluminum frames can dent a lot easier than the chromoly.

Here is chromoly:
suck2.jpg
 
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denting is different then tensile strength. Tensile strength is the strength as it's applied in tension hence the name. Denting has to do with impact strength. DOM and HREW should be pretty close to the same, except HREW will of course have a seam which might be a less on the seam. Otherwise I don't realy see a reason they should be different. Dent resistance should come more from the composition of the steel, most DOM and HREW are 1018 or 1020.

here s blurb on standardized testing for dent resistance:
http://www.sae.org/technical/standards/J2575_200406
 
Weasel said:
denting is different then tensile strength. Tensile strength is the strength as it's applied in tension hence the name. Denting has to do with impact strength. DOM and HREW should be pretty close to the same, except HREW will of course have a seam which might be a less on the seam. Otherwise I don't realy see a reason they should be different. Dent resistance should come more from the composition of the steel, most DOM and HREW are 1018 or 1020.

here s blurb on standardized testing for dent resistance:
http://www.sae.org/technical/standards/J2575_200406
Click to expand...


Ding ding ding we have a winner.........dent resistance is completely different than what the tensile strength of the material is for. I bet if you take a hammer to the same OD, wall thickness tubing of HREW (not on the seam), DOM and 4130: the HREW and DOM will dent the same and with a little less denting on the 4130 because of impact dispersion and rebond characteristics of 4130.

This is why you don't see guys running thin wall 4130 lower links, they will have a higher tensile strength compared to DOM, but will fold on the first rock.
 
CartsXJ said:
Ding ding ding we have a winner.........dent resistance is completely different than what the tensile strength of the material is for. I bet if you take a hammer to the same OD, wall thickness tubing of HREW (not on the seam), DOM and 4130: the HREW and DOM will dent the same and with a little less denting on the 4130 because of impact dispersion and rebond characteristics of 4130.

This is why you don't see guys running thin wall 4130 lower links, they will have a higher tensile strength compared to DOM, but will fold on the first rock.
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i could have sworn that is what i told him about 2 months ago :lecture: ( not word for word but close ) some people you just cant teach!! :doh:
 
Any thoughts on how to decide on the best shape for an application? I'm thinking that round material on rock rails would put an infinite (in theory) amount of pressure on the point of contact and *might* dent more readily? Possibly using HSS would carry the load over a larger area in the same case?

TIA
 
cracker said:
So I have heard / read different opinions on this. Can please someone clear this up?
Click to expand...

You did with the Pirate link. Accurate. Cold forming and carbon content. Something constantly overlooked is CREW...

Now, what is this applicable to? Cage material?

Looking at this from the other direction. :D

It's more a function of velocity and the rock you dent your tube on, as much as the tube you dent on the rock.

--ron
 
Captain Ron said:
It's more a function of velocity and the rock you dent your tube on, as much as the tube you dent on the rock.
Click to expand...

:laugh2:
 
There was a recent article in one of the 4x4 mags about building a buggy, and they were deciding which type of tube to use. One of the tests they did was for denting, so they hit four types of tube with a hammer on the end of the tube. Of course, the aluminum dented the most, then the HREW, then the DOM , then the chromoly bent the least. There was a pretty good difference between how much the HREW and the DOM dented.

I ran out of 1" DOM, so I got some 1" HREW to finish up the cowl and the dash. There is a noticeable difference just cutting the 1" DOM and HREW with a cutting wheel......the DOM is just tougher and takes longer to cut.
 
No numbers to offer but experience says 4130 is by far the toughest; Dom is next in ability to withstand dents and slide over rocks. Dom will dent, gall and tears rather than slide over rocks. My new chassis is all dom on exterior tubes.
P/s - - One caution a lightweight 4130 welded chassis will develop stress cracks in time. Then comes the question will you have a service truck there with a tig welder to do repairs?
 
luvrox said:
No numbers to offer but experience says 4130 is by far the toughest; Dom is next in ability to withstand dents and slide over rocks. Crew will dent, gall and tears rather than slide over rocks. My new chassis is all dom on exterior tubes.
P/s - - One caution a lightweight 4130 welded chassis will develop stress cracks in time. Then comes the question will you have a service truck there with a tig welder to do repairs?
Click to expand...

Same post with dom / crew corrected.
 
luvrox said:
P/s - - One caution a lightweight 4130 welded chassis will develop stress cracks in time. Then comes the question will you have a service truck there with a tig welder to do repairs?
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This is not true, is you develop crack it will most likely be due to a poor design not 4130. And you do not need a TIG welder to repair 4130. Mig will work just fine. 4340 is a different story though and when welded usualy forms a state in which crack can occur.
 
Weasel said:
This is not true, is you develop crack it will most likely be due to a poor design not 4130. And you do not need a TIG welder to repair 4130. Mig will work just fine. 4340 is a different story though and when welded usualy forms a state in which crack can occur.
Click to expand...

Oh really, step back and read what you just posted. Yes, you can probably repair anything with even a butane torch and the correct solder. The word that seems to have slipped by in your statement is "successfully".
 
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