Actually, I didn't know it could be done to any great extent.
Googling around, I find this:
"ISO 15614 consists of the following parts, under the general title Specification and qualification of welding procedures for metallic materials — Welding procedure test:
"— Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys
"— Part 2: Arc welding of aluminium and its alloys
"— Part 3: Fusion welding of non-alloyed and low-alloyed cast irons..."
There's a section of ASME Section VIII that deals with cast iron, and I see that the cast iron materials required by that section are not included in the base metal tables in Section IX, so that doesn't look promising.