Method for cutting large diameter ductile iron pipe
When the volume ratio of oxygen and acetylene is less than 1, a carbonized flame is obtained. Because of less oxygen and incomplete combustion, the flame is longer than the neutral flame and the temperature is lower. Acetylene in the carbide flame is suitable for welding high carbon steel, cast iron and cemented carbide materials. When welding other materials with a carbide flame, the weld metal becomes hard and brittle.
When the ratio of oxygen to acetylene is 1 to 1.2, the flame produced is called neutral flame, also known as normal flame. It consists of flame core, inner and outer flame: near the welding nozzle at the flame core, a bright white; followed by the flame, a blue purple, the highest temperature, about 3150 DEG C, from the front cone at 2 ~ 4mm, and the application of welding wire to the workpiece; the outer flame is orange red. Neutral flame is a flame commonly used in welding. It is used to weld low carbon steel, medium carbon steel, alloy steel, copper and aluminum alloy.
When the oxygen and acetylene volume ratio is greater than 1.2, is formed. As more oxygen, burning, the flame length is shortened obviously, cone tapered inner flame almost disappeared, and a strong desire. Making due to oxygen, the oxidation of metal, so are not widely used, only used for welding of brass, to prevent evaporation of zinc.
