Flaw Detection Tests of LSAW Steel Pipe
Date:2018-07-18 keywords:flaw detection tests
LSAW steel pipes have several flaw detection tests. LSAW steel pipes are now used more and more widely. According to different projects, the standards for using steel pipes are also different. Generally speaking, steel structures, piling, sewage discharge pipes, 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 The safety of the project is 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 for repair, and the repair is completed. After the inspection is qualified, the pipeline can be ensured to be leak-proof 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 lsaw steel pipes is now submerged arc welding. The steel pipes welded by this welding method usually have 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, difficulty in finding small cracks and unfusion, etc. Ultrasonic detection has large thickness and high sensitivity. Convenient, fast, low cost, harmless to the human body. This is the difference between the two.