Cold rolled vs Hot rolled steel

[BlackGMC]

I was wondering what are the difference between to two types of steel and which one should be used for what? For example bars for roll cage, sub frames, etc. I would also like to know which one is stronger and which one you can bend. Oh and price differences.

Thanks

Corey

[astroracer]

The only material you should be using for roll cages and frames is Cold Drawn Seamless DOM (Drawn Over mandrel) for round tubing and, for Sq. or Rect. tubing A513 and, as the stock gets larger with thicker walls, A500.
The Cold Drawn DOM tubing is seamless, has a good surface finish and is generally produced from low carbon 1026 steel.
The A513/A500 is ER Welded, has a seam and is made from HR sheet in gages heavier then 18 but all of the flash is removed for a good finish.
For sheet and thin plate you won't find much of a difference between HR and CR other then the surface finish. CR produces a much smoother surface which requires less work to cleanup.
Most of this stuff is a given when you buy tubing. You will have to specify the DOM for the round tubing. It is more expensive but it is the only material you should use and most racing sanctioning bodies will specify that in their rule books.
As far as prices go you will have to talk to a steel distributor about that. I know it fluctuates a lot and prices have skyrocketed in the last couple of years.
Mark

[BlackGMC]

The only material you should be using for roll cages and frames is Cold Drawn Seamless DOM (Drawn Over mandrel) for round tubing and, for Sq. or Rect. tubing A513 and, as the stock gets larger with thicker walls, A500.
The Cold Drawn DOM tubing is seamless, has a good surface finish and is generally produced from low carbon 1026 steel.
The A513/A500 is ER Welded, has a seam and is made from HR sheet in gages heavier then 18 but all of the flash is removed for a good finish.
For sheet and thin plate you won't find much of a difference between HR and CR other then the surface finish. CR produces a much smoother surface which requires less work to cleanup.
Most of this stuff is a given when you buy tubing. You will have to specify the DOM for the round tubing. It is more expensive but it is the only material you should use and most racing sanctioning bodies will specify that in their rule books.
As far as prices go you will have to talk to a steel distributor about that. I know it fluctuates a lot and prices have skyrocketed in the last couple of years.
Mark

Thank you sir! I do have one question, when I called the steel supply the guy I spoke with said you can't bend CR tubing, he said it would crack? Is he full of crap or what?

[astroracer]

He's full of it. It's obvious he has no idea what he is talking about.
Cold Drawn DOM tubing is bent for roll cages and chassis every day.
Yes, there are some high strength, high carbon steels that don't take well to bending but the low carbon steels this tubing is made from will bend and form just fine. You will have no problems with it...
Mark

[BlackGMC]

He's full of it. It's obvious he has no idea what he is talking about.
Cold Drawn DOM tubing is bent for roll cages and chassis every day.
Yes, there are some high strength, high carbon steels that don't take well to bending but the low carbon steels this tubing is made from will bend and form just fine. You will have no problems with it...
Mark

Thanks again, great advice. Yeah that guy I spoke with didn't really sound like he cared or knew.

[71dusterdan]

sounds like you spoke to one of our steel salespeople. my price as an steel distributor employee for 1 5/8 .135 wall dom tube for my cage was $60. i believe that was for 2 20ft lengths, but i have not got the bill yet. but as astroracer said it is crazy the way the prices are jumping around. everything else astroracer told you is accurate and true. one idea is to find fab shops and try and look for less than stock sizes, leftovers, or "drops" as referred to in the industry. alot of steel salespeople are so busy that they completely do not know how to deal with the layman,hence my recommendation to deal with a fab shop. good luck, Dan

[BlackGMC]

Thanks for the advice guys, that is why I am doing my research ahead of time so I can know exactly what I need and in some cases places to find it cheaper.

[RobM]

you can use seamed (EWS) tubing for roll cages... you dont have to use DOM unless the rules specify

[JMarsa]

Also when it comes to cold or hot rolled, the one with scale (I forget which one it is) for me MIGs more better. I'm not a welder but have had a few classes recently. I'm told the shiney surfaced TIGs better.

--JMarsa

[71dusterdan]

jmarsa, the one with scale is hot rolled