Central Plains Spiral Welded Pipe
Zhongyuan spiral welded pipe is made by rolling low carbon carbon structural steel or low alloy structural steel strip with a certain helix angle (called forming angle) into a tube blank, and then welding the pipe seam. It can use narrower steel belts. Steel pipes can produce large diameter steel pipes. Its specifications are expressed as outer diameter * wall thickness. Welded pipes should be guaranteed to be hydrostatically tested, and the tensile strength and cold bending properties of the welds should meet the requirements.
When processing Zhongyuan spiral welded pipe, welding seam processing is the essence of Zhongyuan spiral welded pipe. The processing of welds is generally divided into three categories. Below we will discuss welds during machining:
A class of central plain spiral welded pipe welds: all welds in a bifurcated pipe. 2. Longitudinal seams of steel pipe walls. 3. Steel pipe ring seam. 4. The pinched knot closes the loop seam. 5. Welded between the diaphragm and the pipe wall. If such welds are inspected by ultrasonic inspection, the inspection rate is 50%, radiographic inspection is 5%, and the quality requirement is B1.
Class II Zhongyuan spiral welded pipe welds: pipe wall joints of steel pipes; butt welds of water retaining rings and stiffening rings and combined welds between them and the pipe wall. If this weld is used for ultrasonic inspection, the random inspection rate is 50%, and the quality requirement is B2 qualified.
Three types of Zhongyuan spiral welded pipe welds: the welds of auxiliary components bear little stress, and will not stop power generation or water injection during maintenance.