The use of screws alone does not idicate that it is cast. Some idications of cast are, thin parting line around perimeter, although it may have been removed, surface texture simmilar to sand, although it may have been smoothened, very close similarity between elements, cracks, lack of true 90 degree angles in edges(draft of 2 degrees or more) also seen as rounding. If it is indeed cast, be carefull as it is brittle, hard to weld without experience, probably old and valuable. If you can't tell the difference, you may not be qualified to work it. Good luck, John Christiansen

Post a picture of it.
Could be anything, from anywhere.

There were a lot of commercial cast iron gates made, around 1900, that were bolted together.
These break, not bend.

But weldable- how?
If its real cast iron, it might weld with some techniques, but not with others. Have your welds held, and not cracked?

Cast iron can be bent, if it is heated very carefully, and worked very gently, not getting it anywhere near red hot. Get it too hot, and it just crumbles or melts.

Really needs photos, screws are sometimes used on wrought iron work and cast iron but without photos it is nay impossible to tell,there was malleable and ductile cast irons in the 19th and in the UK and Europe some amazing cast iron work, Berlin Ironwork comes to mind as does some from England that copied pieces of furniture, Grandfather clocks and leather seats that were amazing so without seeing this piece I think it is difficult for anyone to really know?