Originally Posted by
treekiller
(I know this is old hat for Blue2kss but for everyone else)
Blue2kSS: Do you have a Particular material in mind. As for most typical CrMo Cages they are TIG welded, Often using mild Steel filler. however other fillers can be used based on purpose. Mild Steel cages can be done cheaper since they can be effectively mig welded, and the material is less expensive, however Chromo is more sensitive to temp then Mild steel. Most importantly is not to rush and take your time. and whatever you do don't force cool the welds and they won't be compromised. Pre heating can help, but is not necessary if done carefully.
Lowredcrzr: Yes, PEP (with whom we share a building and info) does full chassis builds, while my end of the building is more mechanical and repair oriented, that end is a full fabrication facility, where at any time you can find 3-4 chassis on jigs he is building for Circle track racers. they also fabricate Full Replica Shelby cobras from scratch. if you want to come by between the two shops we should be able to handle your needs.
give me a call 813-333-1100 we can get some more detailed info. or set you up with an appointment.
I assume you are going to be using 4130 chromoly, and for that particular steel I recommend ER70S-2 filler rod. You can mig chromoly, but TIG would be preferred.
In all reality, TIG should be used (imo) for cages because the heat input is so much more controllable. But there are plenty of cages that are mig welded and they are just fine too.
As far as a mild steel cage, use ER70S-6 filler rod. And again, either processed can be used. You never want to "force cool" metal, leave that to the heat treatment shops. Pre-heating and post heating anything under .095" wall really isn't necessary, but it certainly doesn't hurt to heat it up to around 300 degrees before striking the arc (good insurance). In particular and contrary to popular belief, TIG needs this treatment more so than say oxy fuel or mig because the temperature gradient is so steep at the arc since its so concentrated.
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Mechanical Engineer - Naval Surface Warfare Center PCD, Marine Corps. Counter IED Development
USF Formula and Baja racing Alumni/Consultant