Precautions for use of plastic-coated steel pipes and analysis of connection and installation

precautions for the use of plastic-coated steel pipes and analysis of connection and installation: metal saws or threading machines should be used for extrusion cutting and gas cutting to avoid excessive temperature and the strong extrusion during cutting, which will melt and deform the plastic layer. large-diameter pipes should be cut with a sawing machine. when cutting with a disc saw, its speed should not exceed 800r/min; after cutting, the pipe mouth needs to be trimmed with a scraper, and the section of the cut pipe should be perpendicular to the pipe axis.

preparation before steel pipeline connection;

1. the cut pipe port should be finely filed to smooth the metal burrs;

2. the plastic-coated steel pipe should use a special reamer to chamfer 1/2 the thickness of the plastic-coated layer, and the slope of the chamfer should be 10o-15o;

3. if the coating of the plastic-coated steel pipe is intact at the port, it should be cut into a light inner chamfer with a sharpener; if the port is damaged, it must be repaired until the coating is as a whole without cracks;

4. after grooving, the plastic-coated layer on the flange of the groove will be damaged and must be repaired until the surface of the coating is smooth and there are no cracks or damaged points as a whole;

5. cleaning and processing should use cotton yarn and brush to remove oil, water, and metal chips at the end of the pipe and inside the pipe.

connection method:

1. thread connection: use manual die twisting or electric threading machine to process pipe thread (implement the current national standard gb/t7306), and pay attention to cooling during processing;

2. flange connection: one-time installation method: on-site measurement and drawing of pipeline single-line processing diagrams, after processing, coating and plastic lining, and then transported to the site for installation; secondary installation method: non-coated and plastic-lined steel pipes can be used on-site pipe fittings, flange welding, pipe assembly, and then disassembled for coating and plastic lining processing, and then transported to the site for installation;

3. groove connection: finished grooved plastic-coated pipe fittings should be used first; the groove should be pressed by a special rolling groove machine, and the groove depth should meet the relevant standards (cj/t156-2001).

4. transportation: steel-plastic composite pipes should not be thrown or hit violently, and nylon ropes should be used for hoisting when loading and unloading;

5. storage: steel-plastic composite pipes should be stored flat indoors, and covered with awnings when stored in the open air;