What precautions should be taken when cutting straight seam steel pipe

Generally, the common cutting method of straight seam steel pipe is gas cutting. Gas cutting is to use the heat generated by the combustion of oxygen and acetylene to melt the cut metal at high temperature to produce iron oxide slag, and then blow the slag away from the metal with high-pressure oxygen flow. In this way, the straight seam steel pipe will be cut off.

Using gas cutting straight seam steel pipe has high efficiency, simple operation and neat cutting section, but a layer of oxide film will be attached to the cutting surface. It needs to be removed before welding. During the installation of straight-seam steel pipes, gas cutting method is often used to cut various straight-seam steel pipes with large diameter.

The gas cutting tools for cutting straight steel pipes are cutting torches, which are divided into two types according to the pressure of acetylene, namely, the injection type cutting torch and the equal pressure type cutting torch. Acetylene gas used in gas cutting is supplied by acetylene cylinder or acetylene generator, and oxygen is supplied by oxygen cylinder.

Because gas cutting is dangerous, the operation process must be strictly followed. When cutting straight seam steel pipes with gas cutting method, the following points shall be noted:

1. Whether the straight seam steel pipe rotates or the cutting nozzle is fixed, it shall be kept perpendicular to the surface of the straight seam steel pipe. After the cutting is completed, the cutting nozzle shall be inclined forward gradually and form an angle of 70-80°with the tangent of the cutting point.

2. The selection of oxygen pressure and cutting nozzle can be selected according to the actual situation, which has a great relationship with the thickness of straight seam steel pipe

3. The distance between the cutting nozzle and the surface of the straight seam steel pipe is generally 3-5 mm from the end of the flame core, which should be determined according to the length of the preheating flame and the thickness of the straight seam steel pipe.

4. After the straight seam steel pipe is cut off, the scale slag at the cut shall be ground down and cleaned with a file or hand grinding wheel. At the same time, the end face of the straight seam steel pipe mouth shall be perpendicular to the center line of the pipe.

5. At the end of gas cutting, the cutting oxygen valve and the acetylene valve preheating oxygen valve should be closed quickly.