Anticorrosive Longitudinal Welded Pipe Appearance Inspection: Generally, it is mainly observed with the naked eye, sometimes with a magnifying glass of 5-20 times. Through appearance inspection, surface defects such as undercuts, surface cracks, air holes, slag inclusions, and weld penetrations can be found in the welding elbow welds. It is the same as the erw steel pipe. The external dimensions of the weld can be measured with a weld detector or template.
Non-destructive testing: Inspection of defects such as slag, air holes, and cracks hidden in the weld. The current use of X-ray inspection is common, there are ultrasonic flaw detection and magnetic flaw detection. X-ray inspection uses X-rays to take photos of the welds, and determine whether or not there are defects inside the film and how many defects there are based on the image of the film. Then according to product technical requirements to assess whether the weld is qualified. The basic principle of ultrasonic flaw detection is shown in the figure below. The ultrasonic beam is emitted by the probe and transmitted to the metal. When the ultrasonic beam passes through the metal-air interface, it refracts and passes through the weld.
If there is a flaw in the weld, the ultrasonic beam is reflected back to the probe and accepted, and a reflected wave appears on the screen. Based on the comparison and identification of these reflected waves with normal waves, the size and position of the defects can be determined. Ultrasonic flaw detection is much simpler than X-ray photography and is therefore widely used. However, ultrasonic flaw detection can only be judged based on operational experience, and no inspection basis can be left. For internal flaws that are not deeper than the surface of the weld and microscopic cracks on the surface, magnetic flaw detection can also be used.
SSAW steel pipe before the use of advanced production process of double-sided submerged arc welding, welding can be achieved in a good location, is not prone to wrong edges, welding bias and incomplete penetration defects, easy to control the quality and location of welding. Spiral steel pipe using a special welding process, welding can be achieved in a good welding position, without any defects, can guarantee the qualification of the spiral steel pipe, the quality is well guaranteed.
In the process of forming the spiral steel pipe, the steel plate must be uniformly deformed, the residual stress is small, and the surface should not be scratched. Therefore, the steel plate of the spiral steel pipe must be carefully selected, and the surface should be uniform without scratches. The processed spiral steel pipe has greater flexibility in terms of diameter and wall thickness dimension specifications, especially in the production of high-grade thick-walled pipes, especially small- and medium-caliber thick-walled pipes, and other technologies have unparalleled advantages that can be satisfied.
The user has more requirements on the specifications of the spiral steel pipe. Spiral steel pipe diameter and size specifications to be flexible to grasp, using its own good advantages, we group more users of the broad needs of the spiral steel pipe can be popularized and promoted anti-corrosion Longitudinal Welded Pipe Chongqing anti-corrosion straight seam welded pipe small caliber.