Q&A for How to Perform a Butt Weld Using Electric Arc Welding

A root pass is the first pass, before the cap in a two pass weld, or before the hot pass, fill pass and cap on a multi pass weld.

Ferrous means the alloy contains iron. As the name would suggest, cast iron contains iron, and is therefore ferrous.

As detailed in this article and referred to in general life, when people refer to "arc welding", they are most likely talking about "stick welding", also called "Shielded Metal Arc Welding" (SMAW). However technically speaking, the term "arc welding" actually covers a range of welding processes that use an electrical "arc" to melt and fuse metals together. Therefore welding processes such as MIG, TIG, FCAW, SAW, and more, are considered different forms of arc welding.

Cast Iron is considered a ferrous metal because it contains Iron, which by definition is ferrous. Other examples of "ferrous metal" include but are not limited to: Steel, mild steel, pig iron and stainless steel, among others.

Butt welding is basically "butting" 2 pieces of metal together (as pictured) and welding them together. It is a type of welding joint basically, there are many more, such as fillet joints or lap joints.