(1) The node connection of large-diameter steel pipes is suitable for direct welding, which does not need to pass through node plates or other connecting parts, which saves labor and materials.(2) When necessary, concrete can also be poured into large-diameter steel pipes to form composite members.(

The API standard stipulates that the inner and outer surfaces of the import and export oil casing shall not have folds, separations, cracks, and scars. These defects should be completely removed, and the removal depth should not be less than 12.5% of the nominal wall thickness. Oil casing must be fu

In addition to being used for oil extraction, the emergence of oil casing can also be used as a pipeline for transporting raw materials. To enhance the quality of oil casing, every link in the production process is particularly important, especially the temperature control during the period must be

At present, the commonly used methods for welding steel pipes include electrode arc welding (SMAW), submerged arc welding (SAW), gas tungsten arc welding (GTAW), gas melting arc welding (GMAW), and flux cored arc welding (FCAW). And down welding and so on.(1) The advantages of electrode arc welding