tensile strength

[farmboy weldor]

i have a "source" that says stick welding is stronger than mig, is this true, becuase i always thought that they were about equal, and this "source" also says that stick penetrates deeper, which i also disagree with because you can adjust how far the arc penetrates with the wire speed and voltage...

are my beliefs correct or not?

i also have to complete a job for this person which wants atleast 60000 psi strength in the welds for a truck bed. when ive only got lincoln super arc s-6 which i do not know the tensile strength for but i dont think its 60000??

lincoln says that the superarc LA-75 which is ER80s-Ni7 has a minimum of 80000 pounds tensile strength, but its a low alloy wire... is this ok for mild steel?

i need to use all of this for a truck bed which i have alreayd mentioned is mild steel and im going to do it with .35" so i dont have to adjust my machine much..

and one more question does anybody know if i can run this superarc LA-75 with c-25 gas?


whomever answers these questions thanks alot, it will be really helpful.

farmboy

[Sberry]

All these wires are low alloy, its what makes them stonger than mild steel, just use it and say yes sir, over 60,000, 80 in fact.

[hankj]

The tensile strength identifier is built into the electrode nomenclature. E6013 sticks are 60K tensile strength; ER70S-6 steel wire is 70K, etc. The first two digits tell the story. For wires that are labeled brand-specific, like SuperArc S-6, you can usually look on the spool and find the AWS spec. designation.

Hank

[eric75]

I was taught that stick is more suitable for large work because it is hard to get MIG wire thick enough to carry huge amounts of current and still be flexible. So for welding bridges and armor plating stick gets better penetration with fewer passes. As far as strength, that depends on too many other factors to simply say stick or MIG is better. If you want a counter argument, ask him about impurities, inclusions, pitting, oxidation, and surface finish. I would tend to say MIG is cleaner. For a truck bed, I don't see how it matters.

Sorry I can't recommend a filler or shield gas.

Your fill rod may be rated at a certain tensile strength, and your base metal will be a certain tensile strength. But the Heat Affected Zone in between will always be weakest. There really isn't a non-destructive way to test the strength of your finished part. Did your customer somehow calculate the strength he requires to prevent failure of his truck bed in service? 60KSI sounds a little high to me for a part designed from mild steel.

[Paul Seaman]

Farmboy:
If the welds are completed properly and both are done with a 70,000 psi electrode or rod{er70s-6 vs. e7018** then the tensile strength should be the same. Now that said here comes the boomerang, Technique and manipulation and operator ability are the magic, which do you have more ability to produce a "perfect weld" with.
Also I prefer Harris wire and C25 gas. I buy from a dealer that moves alot of material so I don't worry that it sits around collecting moisture and oxidation, I also try to get the domestic product if I can.

Hope this helps,

[farmboy weldor]

thnx

thanx guys all of this info is alot of help, the person who wants the bed done is a college student who took a beginners class and the teacher tought them about tensile strength in the welds and now hes tensile strenght crayz ...

so it is ok to use c25 with this different wire?

thanks to all

[OldSparks]

I think the request for 60,000 psi tensile strengh is just saying that he would be satisfied with the use of 6010/6011 smaw. I found this Lincoln data page which shows mig wire properties. I'm guessing that the SuperArc S-6 you have is the one shown in the upper chart. Note that it's 'as welded with c-25' results show a tensile strengh of 85,000 psi. Note also the 'as welded' results of the LA-75 with c-25 shows a tensile strengh of just under 80,000 psi.