近一个世纪以来，金属的气焊、气割主要采用氧乙炔焰为热源。然而由于乙炔气的特殊性质和它的不稳定的化学结构，极易引起爆炸。同时电石的严重污染和熔炼时耗能特别高。而今，取代耗能高，污染严重、安全性差、售价高的乙炔气（电石）的新能源已不断被发现，并已用于生产。下? For nearly a century, metal gas welding, gas cutting mainly oxyacetylene flame as a heat source. However, due to the special nature of acetylene gas and its unstable chemical structure, extremely easy to cause an explosion. At the same time, the serious pollution of calcium carbide and melting energy consumption is particularly high. Today, new sources of acetylene gas (calcium carbide), which replace high energy consumption, serious pollution, poor safety and high prices, have been continuously discovered and used for production. under?