bumpin_records

iTrader: (19)

what gas and filler rod would you use weld mild steel to chrome moly if you can? I am using a tig machine.

bgblockelcamino

iTrader: (9)

i use er70s rods. still use argon like you normally would

mrburnout81

iTrader: (8)

do like bgblock said, do not use chromoly filler rod. the weld joints will be very brittle and will break.

Tricked-Out-Toy

iTrader: (4)

Is this in a rule book somewhere? ive been getting conflicting information. My miller rep says to use CM rod. Ive read both all over the internet and im confused.. It makes perfect sense to me that you want a less brittle weld but where is it in the rules? also is the ER70s rod the same as E70S2 rod?

BADD SS

iTrader: (4)

You want to use an ER -70 S2, it will be more ductile.....

99345hp

I know in pipe welding you use a er80s wire, which is a little harder of a weld, but less flexible.

NHRATRANSAM64

iTrader: (12)

ER70S2 Rod with 100% Argon with machine on DCEN (Just in case if you didnt know that already)

2000_SS

iTrader: (24)

we use ER70s-6 where i work when welding P1-P4 material (mild to cr/mo).

Intuition would tell you to use the higher grade rod (80series) and you'd be ok, but that's not the case, you want 70s-6 with your Argon. In all honesty, 80s-b2 or whatever you may/may not have laying around would work, depending on what you're doing...assuming you know how to weld. IF you were welding something thicker that was a high heat pressure boundary, then you'd need some preheat on the material first and definately use the 70S.

99345hp

why do you say that you would definately want to use 70s? On all high pressure steam piping in nuclear power plants when welding P1-P4 they use ER80s-B2 and E8018-B2. With a preheat of 250 degrees.

2000_SS

iTrader: (24)

well that's how we do it where i work, building heat exchangers for those same nuke (and coal-fire) plants. If the customer has specific requirements, we go by that, otherwise our procedure calls for 70s for p1-p4. a lot of us don't agree with that, but that's how we do it in our shop preheat JUST became mandatory on everything...it used to be only on 1/2" or thicker, although we always warmed up any material that was a higher grade than P1. in no way am i saying we do things right where i work, but there haven't been any issues yet...and if there has, it's just more field service work for everyone

I've got to weld some tabs onto my subframe connectors that are 4130 for my new torque arm mount. you can bet i'm not going out of my way to swap wire to do it either. it'll be fine, and if not, lesson learned and i'll do it with 80s-b2, not a big deal i don't think. the differences in composition between 70s and 80s are small enough that on something, or anything, automotive related that i don't worry too much. a roll cage maybe...but not little stuff, 1/4" and thinner. i don't think the loads and forces our cars put out, even in higher hp examples, are enough to really cause a weld failure. i would bet that in half the cases where a weld DOES fail on a car, it's either poor design to begin with, or the welder just didn't know what they were doing.

...just my .02 though.

99345hp

yeah your right. I dont think you will ever find an application on a car that needs 80,000 lbs of tensile strength compared to 70,000.