6011 vs 7018 arc welding rods

Question

What would you recommend in terms of welding a mild steel frame?

It must endure tensile and shear loading in a vibratory sense.

This will be exposed to moisture but will be painted. Cracks, if initiated, must grow slowly so they could be detected before catastrophic failure. We are considering the 6011 (DC) thinking although less strength than say 7018, it provides greater toughness.

Your comments and time are appreciated.-------------------------------------

Answer

I know that in theory the 6011 might provide greater ductility, but in practice, I have found the 7018 to hold up better.

I think the fast freeze characteristics have an affect. Just a guess.

I love 6011 rods but after performing hundreds of fillet weld break tests on both, the 7018 fractures with a more ductile looking fractured surface. Just make sure your 7018 rods are fresh out of the box or out of a rod oven. Also make sure throat size of the welds is adequate.

There is a reason structural and pressure vessel welds use 7018 stick welding rods for Nuclear power houses, bridges, and High rises. 7018 welding rods are time tested and proven along with requiring only very simple and portable welding equipment.

Watch this Video and see what I mean...

7018 welding rods

Feb 23 2011....Old school stick welding using 7018

Sometimes good enough is good enough...and sometimes you cant clean the metal or it just aint worth it