The manufacturing process of welded pipe caps typically includes multiple stages such as raw material preparation, stamping, welding, heat treatment, surface treatment, and quality inspection. During splicing manufacturing, strict requirements are placed on the weld direction, allowing only radial and circumferential welds; the splicing distance should be greater than three times the wall thickness and not less than 100 mm to avoid the heat-affected zone. After splicing, the weld seams of the formed pipe caps must undergo high-percentage radiographic or ultrasonic testing, such as 99.9% radiographic testing, with the acceptance level consistent with the requirements for the equipment shell.
Pulse-echo ultrasonic testing and radiographic testing are the applied non-destructive testing methods. Pulse-echo ultrasonic testing is suitable for detecting defects such as porosity, inclusions, and cracks inside thick-walled pipes; radiographic testing can effectively detect defects such as porosity, slag inclusions, incomplete penetration, and lack of fusion at the ends of pipes and in the welded area, especially advantageous when ultrasonic testing is limited.