Chrome moly identification

By claybokid Date 07-25-2003 01:23

Hey guys,
New to the board...weekend metal worker....putting a rollcage in my 64' ford falcon....I bought a pre-fabbed mild steel bar..and my friend gave me some tubing..which he thinks is chrome moly...meaning I can interchange the two...well...I dont think it's chromemoly....I have researched from where he got it...and it just dosent pan out......so my question is...how do I confirm that it's chrome moly or not. Any tests I can do? the tubing is 1 3\4 X .120. Please help.....Im really wanting to weld up the rest of the cage....and these new pieces fit great..and if they are mild steel..then im in luck...but if they are chore moly...i'll have to ditch them. Thanks in advance.
oh by the way..the tubing have a single seam down the middle...if thats any help.

By MikeR

Date 07-25-2003 15:14

Doesn't matter. When I weld 4130N to mild steel, I use ER70S-2 filler. The joint is only going to be as strong as the mild steel anyway, and if you used 4130N filler, you'd have to post-weld-heat-treat. So just go for it, you'll be fine whether it's moly or mild steel.

By awill4wd (**)

Date 07-26-2003 06:13

We use Cr/Moly basically everyday on sprintcar chassis' repairs here in Australia and if your tubing has a seam in it it almost certainly isn't Cr/Moly. All the Cr/Moly tubing we use is seamless and is usually printed on the tube with removable marker something along the lines of "4130 grade Mil spec condition N"
Even if it was Moly, I'd still use it because it's a much nicer material than normal steel tubing.
Regards Andrew.

By billvanderhoof (****)

Date 07-31-2003 03:26

Check the rule book. Some sanctioning bodies won't allow chrome/moly (NASCAR for one if I remember correctly).
Bill

By aircraft (**)

Date 07-31-2003 10:57

The car has to weigh 3400lbs with driver in it. It don't matter what its made out of.