Chinese saber guards - forged or cast?

[Timo Nieminen]

Iron guards, whether disc/cup, S, knucklebow, or other, are typically forged. I haven't seen a cast antique iron guard. (Not surprising, since you don't want to cast it from cast iron (too brittle), and forging is easier/more economical unless you cast straight from your blast furnace (which gives you cast iron), in the traditional Chinese iron industry.) Some modern (e.g., c. 1900) cup guards look like they're cut from sheet steel, and just have the edge folded over (which you could call cold forging, but you might not want to call forging at all).

Brass guards are usually cast, possibly with some forging/grinding/filing.

I've seen a bronze guard that look forged.

Iron/steel=forged, brass=cast is usual for pre-modern swords. These days, we see modern sword fittings of iron/steel that are cast (and, sad to say, sometimes even cast from cast iron - I broke one of those into tiny pieces). Now we're starting to see them being 3D-printed.