Casting

Wikipedia does it: type 'casting steel' in your browser. Hope this helps

"Casting shall be made of Casting Steel as specified."
Is meaningless without the specification, it should say.

"Casting shall be made of Casting Steel as specified in standard 'abcxyz'."
Or 'any general purpose casting steel available' if they don't actually care.

Send the drawing/order or whatever it is back to the designer/customer and say...
'You havn't included the specification for the steel' (feel free to add blandishments like 'you Muppet' etc for a general effect of grumpiness.)

The previous answer from guest wasn't much help as the first few words from Wiki say.
Steel casting is a specialized form of casting involving various types of steel

I've boldimicated 'various types'
Del
_{(I'm off line for a few days so play nicely)}