1. Origin stage (late 19th century to early 20th century)

In the initial development period of the steel industry, pipelines were mainly manufactured by forging and casting methods, and the pipelines produced by these methods had many problems in terms of dimensional accuracy and quality stability. At the end of the 19th century, welding technology began to sprout, bringing new possibilities for steel pipe manufacturing. At the beginning of the 20th century, with the discovery of the principle of arc welding, people began to try to apply it to the manufacturing of steel pipes.

Early LSAW Steel Pipe production simply aligned the edges of the steel plate and welded it using arc welding. However, due to the rudimentary welding equipment and limited performance of welding materials at that time, the welding process was difficult to control, resulting in uneven weld quality. Moreover, the welded steel pipe undergoes significant deformation and has lower dimensional accuracy. These steel pipes are mainly used in simple industrial and civilian fields such as low pressure water supply and ventilation.

2. Initial development stage (1920s to 1940s)

In the 1920s, welding technology was further developed, and people began to systematically study welding process parameters. During this period, submerged arc welding technology began to emerge, which utilizes the arc beneath the granular flux layer for welding, effectively protecting the weld seam and reducing the impact of air on welding quality. This technology was quickly applied to the manufacturing of LSAW steel pipes.

With the application of submerged arc welding technology, the quality of welds has been significantly improved, and the strength and sealing of steel pipes have been improved to a certain extent. Meanwhile, the improvement of mechanical processing equipment has made the cutting and edge processing of steel plates more precise, providing better conditions for subsequent welding. At this stage, LSAW steel pipes began to be applied to some medium and low pressure chemical pipelines and urban gas pipelines. However, due to the imperfect manufacturing standards of steel pipes at that time, there was still a certain degree of fluctuation in the quality of steel pipes.

3. Technological Innovation Stage (1950s to 1970s)

In the 1950s, with the booming development of the oil and gas industry, the demand for long distance, large diameter, and high pressure transmission pipelines increased sharply. This has led to a significant innovation in LSAW steel pipe manufacturing technology. Firstly, in terms of molding technology, the UOE molding process has emerged. This process first pre bends the steel plate into a U shape, then presses it into an O shape, and then performs welding. The UOE process can produce large diameter and high precision steel pipes, and the roundness and wall thickness uniformity of the steel pipes are well controlled.

Meanwhile, in terms of welding technology, double wire submerged arc welding technology has begun to be applied. Double wire submerged arc welding can improve welding speed while ensuring the quality of the weld seam. Moreover, during this period, new achievements have been made in the research and development of welding materials, and new types of welding wires and fluxes can adapt to higher welding strength and better corrosion resistance requirements.

In the 1960s and 1970s, with the initial application of computer technology in industrial control, some parameters in the production process of LSAW steel pipes began to be automated. For example, parameters such as welding current, voltage, and welding speed can be adjusted through a simple computer control system, which makes the welding quality of steel pipes more stable. During this period, LSAW steel pipes were widely used in oil and gas transmission pipelines, and began to occupy an important position in pipeline systems of some large chemical plants.

4. Maturity and diversification stage of technology (1980s to early 21st century)

In the 1980s, JCOE molding technology gradually emerged. JCOE process is a step by step forming method that involves bending steel plates into approximately circular shapes multiple times and then welding them together. The advantages of this process are relatively small equipment investment, strong adaptability to steel plates, and the ability to produce various specifications of steel pipes. It, together with the UOE process, enriches the production methods of LSAW steel pipes.

In terms of welding technology, with the further development of welding automation technology, automatic tracking systems have been applied in the submerged arc welding process. The system can monitor the position of the weld seam in real time, adjust the position of the welding head, and ensure the accuracy of the weld seam. At the same time, non destructive testing technology has also been widely applied, such as ultrasonic testing, radiographic testing and other methods are used to detect defects in steel pipe welds and internal walls, ensuring the quality of steel pipes.

During this period, the development of materials science also provided higher quality raw materials for LSAW steel pipes. High strength and high toughness steel plates are used in the production of steel pipes, enabling them to withstand higher pressures and harsher environments. Moreover, anti corrosion technology has also made progress, such as using epoxy powder coating, three layer PE coating and other methods to improve the corrosion resistance of steel pipes. The application of LSAW steel pipes in marine engineering, urban centralized heating and other fields is gradually expanding.

5. High performance and intelligent development stage (early 21st century present)

In the 21st century, with the development of the global economy and the continuous growth of energy demand, the performance requirements for LSAW steel pipes are becoming increasingly high. In terms of materials, alloy steels with special properties have been developed for the manufacture of steel pipes, which exhibit excellent low temperature toughness and resistance to hydrogen induced cracking. For example, in oil and gas pipelines in high altitude regions, the new LSAW steel pipe can effectively prevent the pipeline from cracking at low temperatures.

Intelligent technology is widely used in production processes. Robot welding technology has begun to be tested in some large LSAW steel pipe production enterprises. Robots can accurately control welding paths and parameters, improving welding quality and efficiency. Meanwhile, through IoT technology, various data during the steel pipe production process, such as raw material information, production process parameters, quality inspection data, etc., can be collected in real time and remotely monitored.

In terms of application areas, LSAW steel pipes are playing an increasingly important role in the field of new energy, such as the infrastructure of offshore wind power and hydrogen energy transmission pipelines. Moreover, with the increasing environmental requirements, LSAW steel pipe production enterprises are constantly improving their production processes, reducing energy consumption and environmental pollution, and promoting the sustainable development of the industry.