Yeld strength and tensile strength?

I recently had the guy at my local welding supply store tell me that USAB coreshield 11 self-shielding wire is only about as strong as E6011 stick electrode even though it has a E71T-11 classification. So I look up the esab website for this wire:

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and I find that there is a yeld strength and tensile strength field so I was wondering just what the difference is? if yeld strenth is just how strong the weld is then yes I would say he was correct in telling me that the coreshield is only that stong. However the tensile strengh is rated much highter. Now I thought or was always taught that welding electrodes and wires were rated by their tensile strength!.

So the coreshield wire should be rated as a E90T-11 wire shouldn't it?.

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The guy at the store is on dope.

First, the Coreshield 11: Fy = 63ksi (Yield stress) Fu = 90ksi (Ultimate [tensile] stress)

Lincoln's E7018-H4R-MR (Excalibur) Fy = 58ksi Fu = 70ksi

So, the Coreshield 11 is at least a E70 - class electrode, in terms of reported strength, and stronger than E6011.

However, I don't have AWS 5.20 handy, so there is probably some gotcha in the E71-xx spec. Just speculating here, but if you compound this with the cautions against multipass welds (Lincoln has a similar note for their E71T-11) it's probably not good for a full E90.

As for your other question about the difference between yield and ultimate - When you stress a piece of steel below it's yield stress, it will pop back undamaged (err, ignoring fatigue. That gets wonky). After you pass the yield stress, it doesn't pop back all of the way. Example: when you put a piece of bar in a hossfield bender, you can gently push at it with the handle, and it will act like a spring. This is applying stress below the yield point. Once you push hard enough to bend the bar, you have exceeded the yield stress. Tensile stress is easier - it is the point where it breaks. This is why it is also called the Ultimate stress.


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Rich Jones

Yield strength is the point where where stress on the material goes from the "elastic" to the "plastic" range of deformation. (stress = ksi, strain = distance)

Tensile stress = ksi It can be in either the "elastic" or "plastic" range, as can 'fiber bending stress' and 'shear stress'.

In the design of structural steel members the unit of stress is customarily "ksi" ...... meaning 'kips per sq. inch'...... a 'kip' is 1000 lbs.

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The tensile strength you are referring to is "nominal" tensile strength. It is the minimum tensile strength the filler metal is required to have in the as welded condition. It is quite possible for the actual tensile strength of some filler metals to significantly exceed the nominal tensile strength. For example, ER70S-6, has a nominal tensile strength of 70 ksi, but may actually exhibit a tensile strength of 85-90 ksi in the as welded condition.

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