What Is Pipe Welding?
Welded steel pipe refers to a steel pipe or steel plate that is bent and deformed into a circular, square or other shape and welded with a seam on the surface. The blank used for welded steel pipe is steel plate or strip steel.
- Since the 1930s, with the rapid development of continuous production of high-quality strip steel and the improvement of welding and inspection technology, the quality of welds has continuously improved, and the variety of welded steel pipes has increased, and has replaced them in more and more fields
- The "Twelfth Five-Year Plan" outlines that the total length of oil and gas pipelines will exceed 150,000 kilometers by 2015, which will increase 90% from 2010. It is estimated that China will need about 7-8 million tons of welded pipes in oil and gas pipelines in the next 4 years, of which X80 steel grade is about 5 million tons and X70 steel grade is about 3 million tons. The annual demand of SSAW (spiral submerged arc welded pipe) will exceed 5 million tons, and the annual demand of LSAW (straight seam submerged arc welded pipe) is more than 2 million tons.
- During the "Eleventh Five-Year Plan" period, China's oil and gas pipeline construction continued to develop rapidly. Especially with the rapid growth of natural gas demand, natural gas pipelines have become the focus of pipeline construction. By the end of the "Eleventh Five-Year Plan" period, China has accelerated the deployment of oil and gas pipeline networks, and the nationwide oil and gas backbone pipeline network has been initially completed. In the future, China's oil and gas supply guarantee capabilities will be further enhanced. Data show that as of the end of 2010, the total length of oil and gas pipelines in China was about 85,000 kilometers, including 45,000 kilometers of natural gas pipelines, 22,000 kilometers of crude oil pipelines, and 18,000 kilometers of refined oil pipelines. Oil and gas pipeline grid bureau covering the whole country and connecting overseas.
- China's "Twelfth Five-Year Plan" outline clearly proposes that China-Kazakhstan crude oil pipeline phase II, China-Myanmar oil and gas pipeline domestic section, Central Asia natural gas pipeline phase II, and the West-East Gas Pipeline 3, 4 and other main projects, And build supporting branch lines and urban pipeline networks. By 2015, the total length of oil and gas pipelines will exceed 150,000 kilometers, an increase of 90% over 2010. This means that the new pipelines in the next 4 years will be equivalent to the total of the past 50 years. The compound growth rate is at least 14%, which provides opportunities for oil and gas pipeline companies.
- As China continues to increase investment in oil and gas pipelines, the annual demand for SSAW for oil and gas pipelines during the "Twelfth Five-Year Plan" period will exceed 5 million tons, and the annual demand for LSAW will exceed 2 million tons. [2]
- Corrosion resistance is strong in acidic environments when Ni is contained in T-welded steel pipes. In environments containing sulfuric acid or hydrochloric acid, the higher the Ni content in T-welded steel pipes, the stronger the corrosion resistance. Under normal circumstances, corrosion can be prevented by adding Cr to the T-shaped welded steel pipe. Poor edge edges are another important cause of misaligned edges. Effects of changes in mass flow rate, heat flux density, and structural parameters (ratio of spiral curvature diameter and T-welded steel pipe diameter Dc / D) on the saturated bubble boiling heat transfer coefficient in a vertical spiral tube.
- In the production of T-shaped welded steel pipes, misalignment occurs from time to time, and its influencing factors are many. In production practice, steel pipes are often degraded due to excessive tolerances. Therefore, it is necessary to analyze the causes of spiral steel pipe misalignment and preventive measures.
Due to the poor shape and dimensional accuracy of the head and tail of the uncut edge steel strip, the steel strip is liable to cause hard bends during docking and cause misalignment. Simulation parameter range: vertical pipe: pipe diameter D = 10mm, pipe length L = 660mm; three types of vertical T-shaped welded steel pipes: pipe diameter D = 10mm, the change in the ratio of the curvature diameter and spiral pipe diameter of the T-shaped welded steel pipe is Dc / D = 15, 20, 25, spiral pitch Pt = 20mm, tube lengths are L = 503mm, L = 660mm, L = 817MM. Mass flow G = 200 ~ 400Kg / (m'2 · s),
- Weight of welded steel pipe kg / m = (Od-Wt) * Wt * 0.02466 Note: where Od is the outer diameter and Wt is the wall thickness
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