25CRMO4 or AISI4130 for single seater spaceframe

[BrianGar]

My supplier can give me both in 'any' size.

I have not yet made my mind up if I'll tig, or gas weld as at the minute, from a lot of research gas seems to be more favorable (albeit a little old fashioned) for a few reasons. The main one being, heat treatment and the smallness of the HAZ with tig.
Im pretty sure no heat treat is needed if gas is used and allowed to cool slowly, where-as tig requires gas also to pre and post heat the weld zone due to a lesser area heat zone.
I use both, gas and tig at the minute, and know both techniques for 15yrs, no extra machines will have to be bought pending choice.

Im sure my supplier will advise me also, but what type of filler should I be using for both tube specs as Im getting conflicting information as to rod choice as it stands for both tubings listed above.

To give a rough idea of vehicle, Im looking at a space frame single seater, circa 400hp, 135mph top speed to be ran on 'smooth tarmac' tracks/circuits.

Thanks in advance,

Brian,

 

[Tmoose]

Lincoln Welding has some 4130 welding procedures in their Motorsports section knowledge base.

 

[BrianGar]

Thanks, Ill check that out. Any preference as to which tubing steel to go for?

BG.

 

[mrfailure]

I am not making a recommendation, but for this comparison 25CrMo4 is considered equivalent to 4120, although I would note carbon content (0.22 - 0.29) is higher than 4120 (0.18 - 0.23). Source: Worldwide Guide to Equivalent Irons and Steels from ASM International.

Aaron Tanzer

http://www.lehightesting.com