Pipeline transportation, as an efficient means of special transportation, has played an increasingly important role in oil and gas transportation and other fields. At present, domestic large-diameter transportation pipelines are mainly constructed of spiral welded steel pipes. To ensure the reliable operation of the transportation pipeline, the quality of the spiral steel pipe used must be strictly guaranteed. Therefore, researching and adopting an effective online ultrasonic automatic flaw detection system has become an inevitable choice for steel pipe production enterprises. Compared with foreign countries, the level of testing equipment in my country is relatively backward. The testing of weld seams of steel pipes is carried out by manual or semi-automatic equipment. possible defects. In international bidding activities, the steel pipe production enterprises that participate in the bidding are usually required to have relatively complete testing measures. Although some companies have spent huge sums of money to import some automatic testing equipment from abroad, due to the limitations of domestic production and testing supporting conditions, other The use effect is often not ideal, resulting in many imported equipment being idle, wasting a lot of money. The current situation greatly limits the international competitiveness of domestic steel pipe manufacturers.
Because of its mature manufacturing process and low cost, spiral steel pipe is a kind of steel pipe mainly used in fluid-conveying pipelines. At present, continuous forming and submerged arc welding are generally used to manufacture spiral steel pipes. There are two types of forming methods: inner bearing type and outer embrace type. Since these two forming methods are generally not enough to form, the steel pipe will have a large residual stress after manufacture, which reduces the pressure-bearing capacity of the steel pipe. After theoretical analysis, the formula for calculating the residual stress of the steel pipe in the case of insufficient forming is given, and the residual stress of the inner-supported spiral steel pipe is measured to verify the correctness of the formula for calculating the residual stress given in this paper. The manufacture and application have a guiding role.
The non-destructive testing of steel pipe welds has always been an important problem that is difficult to solve and needs to be solved urgently. It is urgent to develop automatic weld testing equipment suitable for the production conditions of our country. Different ultrasonic methods are used for flaw detection of steel pipes, and the accuracy of flaw detection varies greatly. Due to the difference in the geometry of the weld bead and the uncertainty formed by various composite defects, it is difficult to automate the ultrasonic flaw detection of steel pipes, and the influence of human factors is also great. How to improve the validity and reliability of flaw detection results has become the focus of ultrasonic automatic flaw detection of steel pipes. After investigation and research and many years of experience in steel pipe flaw detection, a full-digital ultrasonic flaw detection system that integrates a precise probe tracking system, single-chip microcomputer technology, and computer signal processing functions has been developed under the spiral state of steel pipes. Compared with traditional flaw detectors, the spiral steel pipe digital online ultrasonic automatic flaw detection system has the following advantages: (1) Fast detection speed, automatic detection, calculation, recording, automatic depth compensation, and automatic setting of sensitivity. (2) The detection accuracy is high. The system performs high-speed data acquisition, quantification, calculation, and discrimination on the analog signal, and its detection accuracy can be higher than the detection results of traditional instruments. (3) Record and archive inspection, the digital ultrasonic flaw detector can provide inspection records up to defect images. (4) High reliability and good stability, can collect and store data comprehensively and objectively, and perform real-time processing or post-processing on the collected data, analyze the signal in the time domain, frequency domain, or image, and also use the mode Recognition grades the quality of workpieces, which reduces the influence of human factors and improves the reliability and stability of retrieval. (5) CCD camera tracking sensor is used for seam tracking, which has the advantages of high detection sensitivity, no fear of water, no fear of air, simplicity and reliable, etc.
Spiral welded steel pipes are widely used in petrochemical, heat pipe network, and urban water supply and drainage projects, especially in long-distance oil and natural gas pipelines. Almost all oil and gas field pipeline networks use spiral welded steel pipes, which have high safety, durability, and economic rationality. Since the diameter of the spiral welded steel pipe is generally not limited by the width of the plate, it can be made of plates of various specifications.
Post time: Jul-03-2023