02T/AWS6

Can you weld steel tube adapters to chromoly tubing???

99345hp

I would say yes. I would guess you are using tig? If you are using tig I would get some ER80-S filler wire. In my industry that is the wire we use to weld chromemoly pipe. What I would recommend is to take two scrap pieces of the same material and weld it together. If it will weld together, the next thing to do would be to try and destroy the weld. If you have a press use that to bend the two pieces at the weld joint. Let me know how it works.

Benner

iTrader: (2)

You can do it but you're more likely to get corrosion around the weld sites (even though there corrosion resistant) since your welding to dis-similar metals together but it can be done with patience.

02T/AWS6

ok thanks for the input, i'm making my own torque arm and my friend who is an amazing tig welder will be welding them together so i know he can weld it if the metals are compatible.

greg campbell

iTrader: (2)

Yes. Use the reccomended filler rod with the type of tubing you are welding. Mild steel and chromemoly are similar in their makeup. Chromemoly filler (and the metal itself) "wets-up" nice during welding, thus mixes well with mild steel at the atomic level. It's a little more expensive than the ER70S-D2 mild steel rod because of its higher manufacturing costs and refinement. Make sure to clean all weld areas thoroughly, at least one inch from the weld area:wire brush, sanding, scothbrite...

1FastBrick

iTrader: (16)

If I am not mistaken don't you have to heat treat a part welded with a cromoly filler rod to prevent it from cracking. were as with the ER70-2 rod you don't need to heat treat after welding???

Edit : Read this link I found it in another thread about welding cromoly in this section... Good info and supports what I said about choice of filler rod

http://www.netwelding.com/welding%204130.htm

BADD SS

iTrader: (4)

Use ER70-S2 wire...

http://www.netwelding.com/welding%204130.htm

A very valuable, informative and correct source to learn alot from... We talk about this site on miller's forum all the time.

xfactor_pitbulls

iTrader: (16)

Blah, I would use 308ss filler. Never use Chromoly filler, its always carbon or stainless based.

y2khawk

iTrader: (5)

umm, NO!

70S2 or 80D2, that's it. For what we do that's more than enough weld strength. The 80 will produce a slightly more brittle weld than the 70, but 9 times out of 10 the weld will be stronger than the parent metal around it.

Might want to check you tube ends as well, as most of them are 4130 anyway. Not like it really matters though

moly to mild is VERY common in racecar stuff.

If you're doing 304 stainless, then use your 308 rod otherwise leave it in the tube

99345hp

You are right, do not use stainless filler unless welding stainless. We use 309 stainless filler on carbon, but only when welding carbon steel to stainless steel. To what everyone else has said and stick with the carbon based filler material. If you are concerned about the weld strength, than you can do as I said and practice and try to destroy the weld.

CTSmechanic

iTrader: (2)

ER 312... good for dissimliar metals...

SBMZ28

iTrader: (1)

Lincoln makes some Bluemax 2100 which is specific for Dissimiliar metals. It's a little expensive though. You may try Grainger.

Old Geezer

iTrader: (3)

When using threaded ends, I always drill the tube, and add a couple plug welds, in addition to the main weld.
I built, and tested the first RANDOM Technology torque arms. We used direct thread tubing, and eliminated the expense of the threaded ends.

greg campbell

iTrader: (2)

99345 is right, 309 is used for joining carbon steel to stainless, 309-16 in the SMAW process. I've tried 308 rod on GTAW (tig) on stainless and mild steel, there was a difference in the way the filler metal "wetted" during welding. I would not reccomend stainless rod on mild steel or chrome molly. Remember it is similar mild steel, it's magnetic, and just has chromium and molybdenum added to increase its rigidity and tensile strength. That's why you can use a thinner wall thickness and get the same strength!

cooks 7

If your friend is an amazing tig welder than it should be no problem for him/her. Like was stated earlier mild to chromoly is pretty common in race welding, your chromoly cage likely is welded to mild steel floor plates unless it welded to your frame and then it's still mild to chromoly, I use the ER70 -S2 (used for mild to mild as well) for mild to chromoly, it welds up nicely no different than mild to mild or chromoly to chromoly. I second the staying away from stainless filler rod unless welding stainless. It was questioned earlier about heat treating but most people beleive that the relatively thin cross section of most chromoly in automotive applications doesn't require heat treating, but dont quench your welds, just let them air cool and you'll be fine.