Flame spraying uses fuel gas acetylene, propane, methyl acetylene-propadiene (MPS), hydrogen or natural gas and combustion-supporting gas oxygen as a heat source. The spraying material enters the flame by a certain transmission method and is heated to a molten or softened state. Then, rely on gas or flame to accelerate the jet to the substrate. According to the different spraying materials, it can be divided into wire flame spraying and powder flame spraying.