Neutral flame or oxidizing flame for oxyacetylene spraying

       What kind of flame is used for flame spraying depends on the material to be sprayed. The temperature of flame spraying is relatively low. It is generally used to spray self-fluxing alloys or non-metallic coatings, and neutral flames are usually used.

①If an oxidizing flame is used, the alloy material will be oxidized, and there will be peroxides in the coating, which will affect the quality; ②If a carbonization flame is used, the excess acetylene in the flame will decompose into C and H2 and penetrate into the alloy. It has a great impact on nickel-based and iron-based alloys, but has little effect on cobalt-based-copper-based alloys; ③ If a neutral flame is used, the flame contains very little oxygen, and the alloying elements are less burned before and after spraying. In order to obtain a stable neutral flame, O2 and C2H2 should be kept constant.

According to the combustion equation, the ratio of fuel gas and oxygen of the three flames can be known. In actual work, because the oxygen in the air participates in the combustion, acetylene and oxygen are 1:1 to obtain a neutral flame.