Year1
- 规格：
- DN700
- 标准：
- GB9711
Wall thickness
Song type material
Song type standard
Song type application
Anti-corrosion treatment or black paint on the outside, often used in pipeline steel pipes for oil and natural gas transmission. Among them, for and two levels. Pipeline steel pipe is a pipeline pipe that belongs to the American Petroleum Standard. Pipeline pipe is used to transport oil, steam, and water extracted from the ground to oil and natural gas industry enterprises through pipeline pipes. Line pipes include seamless pipes and welded steel pipes, and their pipe ends have flat ends. , the connection methods of the threaded end and the socket end are end welding, coupling connection, socket connection, etc. With the development of pipeline steel plate technology and the progress of welded pipe forming and welding technology, the application scope of welded pipes for pipelines is gradually expanding, especially in the large-diameter group spacing range, the advantages of welded pipes are more obvious. Coupled with the cost factor, welded pipes have been in The line pipe segment occupies a dominant position.
Song Dynasty spiral steel pipe feeds the strip into the welded pipe unit. After being rolled by multiple rollers, the strip is gradually rolled up to form a circular tube blank with an opening gap. Adjust the pressing amount of the extrusion roller to make the weld seam The gap should be controlled at
~, and both ends of the welding joint should be flush.
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If the gap is too large, the proximity effect will be reduced, the eddy current heat will be insufficient, and the inter-crystal bonding of the weld will be poor, resulting in lack of fusion or cracking.
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If the gap is too small, the proximity effect will increase and the welding heat will be too high, causing the weld to be burned or the weld to form a deep pit after being extruded and rolled, affecting the surface quality of the weld. .
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After Song Ti heats the two edges of the tube blank to the welding temperature, under the squeeze of the extrusion roller, common metal grains are formed to penetrate and crystallize with each other, and finally form a strong weld. If the extrusion force of the spiral steel pipe is too small, the number of common crystals formed will be small, the strength of the weld metal will decrease, and cracking will occur after stress. If the extrusion force is too large, the molten metal will be extruded. The weld seam not only reduces the strength of the weld seam, but also produces a large number of internal and external burrs, and even causes defects such as welding lap seams.
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