chromoly tubing for cage ?

[GregWeld]

4130 Chrome Moly tubing can be welded with ER70S or ER80S (stronger)... using TIG... best with a gas lens... and keeping the heat under control or you pull the carbon out. Pre and post heat are only required on .125 wall or thicker. Quenching would cause cracking.

[GregWeld]

312 SS rod -- also called "supermissle" -- EASY to weld with - wets out nice and doesn't magnetize.... good material choice for Chrome Moly tube and has a tensile strength of 120,000 which is higher than the 70 or 80 (which is 70 or 80,000 depending on the rod used as the numbers indicate).

[ccracin]

From what I recall all Nextel Cup chassis are Cold Drawn Seamless tubing.

DOM is not necessarily stronger than ERW (Electric Resistance Welded) for a given alloy. DOM (Drawn Over Mandrel) has a more consistent size and shape so that it has consistent properties in any direction for lack of a better term. DOM still does have a seam that is fused therefore you still have a heat affected zone down the length of the tube. After the tube is formed and welded, it is then pulled over a mandrel to accurately form the shape which provides a more uniform wall thickness, ID, OD. This also does some cold working and can possibly add some strength.

CDS (Cold Drawn Seamless) tubing is formed from a solid carbon steel bar by drawing it over a mandrel to form it's shape. Therefore there is no welded seam. This process also cold works the steel and improves it's mechanical properties.

Chromoly Tube is basically CDS tubing made from 4130 alloy steel. Standard CDS tube is typically 1018 or 1020 carbon steel. The 4130 alloy has greater tensile and yield strength than 1020 while maintaining good ductility. However it does require certain things be done before during and after the welding process to ensure the weld integrity as well as the quality of the base metal in the heat affected zone of the weld.

As said before, Chromoly is not lighter than CDS or DOM. Because it has better mechanical properties, you can typically use less wall thickness for a given tube than CDS or DOM.

I am not a metallurgist or welding engineer, but it is my opinion that you should not attempt to use 4130 unless you are well schooled on the requirements of properly welding this material. I have seen failures that can be attributed to not doing it properly and by people that say gee "I have done it like this for years with no problem". They just got lucky for years. I can't go into the proper procedure because frankly, I don't know it. Meaning there are different methods for different thicknesses, weld processes and weld joint configurations.

Honestly, these same considerations should be taken into account for any structural/safety related weld. I can weld, but when it comes to these types of welds I get a friend and certified professional welder to do it for me. I think it is worth it.

Well, thus ends me running off at the mouth. Don't take this as gospel just me trying to pass on some information I picked up along the way. Sorry for the book. Hope it helps.

[GregWeld]

I think Chrome Molly is only ever used where WEIGHT is a major factor -- otherwise - why bother... DOM is fine for most of us...

What book Chad! You only got thru page one!

[ccracin]

Originally Posted by GregWeld

I think Chrome Molly is only ever used where WEIGHT is a major factor -- otherwise - why bother... DOM is fine for most of us...

What book Chad! You only got thru page one!

That's all I could do, I only type with 2 fingers!

[Blake Foster]

Originally Posted by GregWeld

I think Chrome Molly is only ever used where WEIGHT is a major factor -- otherwise - why bother... DOM is fine for most of us...

What book Chad! You only got thru page one!

i would say your 100% correct on this one.
CM is typically 30%-35% lighter that .134 wall dom. so if you had 80 feet of material in a road race cage you might save 50-80 lbs (just guessing here) the DOM is 1/2 the cost of CM if not less. the labor savings is probably 1/2 for the install
that being said i have 3 lengths of CM sitting here waiting for the new project to arrive, but if it wasn't on the rack i don't think i would spend the extra $$$ to use it. if i was building a Comp Eliminator or Prostock car then there wouldn't even be an option it would be CM. but a track day car or super class car, there are alot of other places to loose 50-80 lbs.

[ironworks]

Originally Posted by killer69

i would say your 100% correct on this one.
CM is typically 30%-35% lighter that .134 wall dom. so if you had 80 feet of material in a road race cage you might save 50-80 lbs (just guessing here) the DOM is 1/2 the cost of CM if not less. the labor savings is probably 1/2 for the install
that being said i have 3 lengths of CM sitting here waiting for the new project to arrive, but if it wasn't on the rack i don't think i would spend the extra $$$ to use it. if i was building a Comp Eliminator or Prostock car then there wouldn't even be an option it would be CM. but a track day car or super class car, there are alot of other places to loose 50-80 lbs.

I know I could stand to lose more weight personally on my body, then I ever could with a 4 or 6 point cage. I bet you lose more weight with Lexan windows or Anvils carbon parts is you have a 1st or 2nd gen camaro.