Cromoly vs mild steel

[Mountaintech]

Interested in peoples thoughts regarding a arm construction. The weight savings advantage of chromoly is obvious, but the ruggedness of mild steel seems to be very underrated. Mild steel parts have saved my butt (in terms of being able to ride out) more than once where the same part in chromoly would have been destroyed. I guess the question is, is the extra weight savings worth it?

 

[kennyspec]

Isn't the general rule that chromo parts are "twice as strong" as mild so therefore you can use a tube half of the thickness? I guess it depends on the application. Is the sled just used for deep snow powder riding or is it a ditch banger? What is the most common size and thickness used in chromo a arms? What if you went just over the 1/2 as thick as mild rule and your arms would still be lighter than stock and probably just as strong, if not a little stronger.

 

[ruffryder]

Here is some reading for you..

http://www.pirate4x4.com/forum/general- ... eel-2.html

It seems that most cromoly fixtures are not properly heat treated afterwords and therefore are not stronger then the same fixtures made from mild steal. At least that is my recollection of the thread. Haven't read it in depth in a while.

Let me know what you think.

 

[Mountaintech]

I agree. Cromoly is stronger and parts can be lighter because of decreased wall thickness. I have had better luck with mild steel parts in the past because they seemed to be less prone to catastrophic failure.

 

[Mtnviper]

I think that also depends on wall thickness of the chrome moly as well.
On my old Viper I had a set of chrome moly trailing arms on it and I would have to have cracks along the welds re-welded every couple of years. The trailing arms where made out of fairly thin wall tubing and I feel that had the wall thickness been a little thicker, the arms would have been more resistant to heat stress along the welds.

Fast forward to Nytro which I had a chrome moly subframe and TS chrome moly A arms on it. With that set up I whacked a tree pretty hard. It bent the lower A arm pretty bad (the chrome moly subframe was un-damaged), but it did not crack or fail and I was able to ride the sled out.

Bill