Provided is an iron-based nonelectric welding device. The body of the iron-based nonelectric welding device is a disposable die filled with iron-based soldering flux, wherein the iron-based soldering flux contains 48%-57% of ferric oxide powder, 15%-25% of metallic aluminum powder, 0.2%-2.8% of metallic nickel powder, 0.5%-4% of fluorite powder, 1%-6% of silicon dioxide powder, 3.1%-8.2% of calcium oxide powder and 12%-21% of metallic iron powder. The disposable die is formed through single-pressing and stoving after rick fat oil is mixed with standard sand. The soldering flux mainly comprises ferric oxide, ferrous powder and a little of nickel powder, and iron-nickel alloy is produced on soldering points through self-propagating reaction after ignition; the iron-nickel alloy is approximately equal to parent metal steel of a grounding device in electrode potential, and galvanic corrosion of parent metal cannot caused. The die is good in thermal insulation effect and low in price, links of cleaning, die sinking, die filling and the like are reduced through one-time use, time is saved, and scalding risks of staff are reduced. The reaction speed of soldering flux ranges from 45 seconds to 60 seconds and longer than common self-propagation by 20 seconds, the possibility of splashing of reaction products is reduced, evacuation is facilitated, and safety is good.