There is absolutely nothing to compare with real, actual wrought iron for forge welding. Wrought iron already contains its own flux.
When forge welding steel one must use something for flux. Check with the experienced blacksmiths here.
High carbon steel, for example 1095, tolerates less overheating than does low carbon steel or wrought iron, before it burns. Some 19th century guy had a magic process for forge welding cast steel (call it 1095, if you will) without burning. What he did, minus the 19th century terminology, was to decarburized the surface a bit. That is, he heated it up in air so that some of the carbon oxidized out of the surface. Then he had a low carbon steel surface to heat in the forge, which low carbon surface could better take a welding heat with less chance of burning.
When steel, or iron, is "burnt" in the forge, well, it is a spectacular show & the iron is now useless for anything but remelt scrap.
That "Real Wrought Iron" website is fascinating. The last iron puddled in the US was near Pittsburgh in 1961, probably by the A.M. Byers company. For good reading get thee to abeboks.com and look for "Wrought Iron, its manufacture, characteristics and applications", by James Aston and Edward Story.
Between 1018 & 1010, speaking strictly as a metallurgist no practical experience with either, I would prefer the lower carbon 1010. That little lower carbon should be marginally less likely to burn.
Oh, and I do know how to burn wrought iron. Burnt my first iron right after I made may first & only forge weld in wrought iron.
Had an old boss, welding guy, who didn't like aluminum killed steel for forge welding. That would be industrial, big machine, forge welding. The aluminum content--and this is just a few tenths of a percent aluminum--made for a "dry weld" I don't know what he used for flux. He did know his stuff. He was about 65 years old in 1970.