If the base metal is unlisted, it must be approved by the Engineer. The proposed WPS must be qualified in accordance with clause 4.

Cast steel can have wide ranges of alloy additions, so the chemistry of the actual casting may not match that of the casting used for qualifying the WPS. One should give careful consideration to the material specification and if this is new construction, hold the foundry to tighter ranges than permitted by the base metal specification. If this is a repair, perform a chemical analysis on the actual casting.

Cast steels typically have increased amounts of sulfur, so an electrode with high manganese may be useful in mitigating cracking  from the sulfur.

Good luck - Al