Hello, What is the difference between using ER70S-2 rather than ER70S-6 for TIG welding steel? I have read that the S-2 is "triple de-oxidized" with aluminum, titanium, and ziconium which makes it a good choice for welding porosity prone materials (or dirty materials when GMAW welding). However I have also read that the S-6 rod is the best for porosity prone materials (or again dirty steel with GMAW) due do its higher manganese and silicon content. So what is better: more Mn and Si, or the "triple deoxidizer" cocktail?
I work in college welding lab that relies heavily on donated metal, and some of the steel we get shows some porosity when TIG welded. We are looking to stock up on filler materials, and I want to get TIG rod that will be helpful in minimizing porosity.
Another question: I read somewhere that ER70S-2 is a better choice for TIG welding 4130 chrome-moly (for weld joints needing high ductility, and that will NOT be heat treated after welding). Does anyone have thoughts on why that is? Thanks much!