Several Flaw Detection Tests For Q345B Straight Seam Steel Pipe

Submerged arc welding pipe is now used more and more widely than seamless steel pipe. According to different projects, the standard of steel pipe is different. Generally speaking, steel structure, piling, sewage discharge pipe, etc. There is no requirement for flaw detection of steel pipes, no need for flaw detection, and the projects used for flaw detection are: natural gas pipelines, oil pipelines, fire pipelines, etc. These projects have extremely strict requirements for flaw detection, and some strength flaw detection standards are related to engineering safety. And even related to the safety of people's lives.

There are two types of flaw detection that are most widely used. One is ultrasonic flaw detection. This type of flaw detection is to use ultrasonic energy to penetrate into the depth of the metal material and to reflect at the edge of the interface when one section enters another section. A method of part defect, when the ultrasonic beam passes from the probe to the inside of the metal from the surface of the part, the reflected wave occurs when the defect and the bottom surface of the part are encountered, and the pulse waveform is formed on the screen of the detecting instrument, which is based on the pulse waveform.

To determine the location of the defect and the size of the defect, cracks, inclusions, stomata, blisters, etc. When a defect is detected, there will be a professional technical manual repair, the repair is completed and the defect is regarded as a qualified finished product, flaw detection After passing the project, it can ensure that the pipeline does not leak during the use of the project, and the pipeline is guaranteed.

The other type is X-ray flaw detection, which is also widely used. X-ray is a method of detecting internal defects of a weld by using a certain kind of radiation. X-rays can penetrate the metal material to different degrees, and cause photosensitivity to the photo film. Using this property to detect welds, because the weld defects have different absorption abilities, the intensity of the rays falling on the film is different, and the sensitivity of the film is different, so that the shape of the defects can be accurately and reliably detected., location and size.

The welding used for straight seam steel pipes is now submerged arc welding. The longitudinally submerged arc welding pipe welded by this welding method usually has no welding defects. The difference between ultrasonic and X-ray lies in those, X-ray inspection, low sensitivity, inconvenient, slow detection speed, high cost of radiographic film, and it is not easy to find small cracks and unfused. Ultrasonic inspection has large thickness, high sensitivity and convenience. Fast, low cost, harmless to the human body. This is the difference between the two.

A worker from a steel pipe company, which is located in China.