Introduction to the content of inspection standards for thick-walled straight seam steel pipes

The development of seamless steel pipes focuses on energy saving and emission reduction technology. Thick-walled straight seam steel pipes are to develop high-grade (X100) and large-wall thickness (≥60mm) products. The whole pipe is expanded in diameter, which is the best way to eliminate residual stress in spiral submerged arc welded pipes. A reasonable plan, straight seam high frequency welded pipe should play its advantages in heat treatment of weld seam. When formulating relevant policies, it is advisable to focus on macro-control rather than the approval of specific units; it is necessary to eliminate the contradiction of overcapacity and prevent blind comparisons of overcapacity.

At present, my country's steel pipe product structure is in a pattern of excess low-end products and insufficient products, but this does not mean that all enterprises must develop in the direction of products, each enterprise should determine its market positioning according to local conditions, or personalized, or personalized, Organization, while preventing homogenization. As a result, enterprises can grasp the correct orientation in the adjustment process of the technical structure and product structure. Given the characteristics of small, large, and scattered steel pipe enterprises, especially private enterprises, enterprises can be integrated into industrial groups according to the characteristics of the production process, product scale, technical equipment, and so on. There are many types of steel pipes, and each type has different characteristics. Therefore, in terms of technology and product structure, it is necessary to complement each other's advantages and avoid weaknesses. Regarding the structural adjustment of the seamless steel pipe industry, energy-saving and environmental protection technologies should be actively adopted, among which the online normalization technology, the regenerative heating furnace and the waste heat utilization of the annular furnace and other technologies have significant energy-saving effects; Comprehensive utilization to realize circular economy.

Thick-walled straight seam steel pipes and spiral steel pipes are both types of welded steel pipes. They are widely used in national production and construction. Thick-walled straight seam steel pipes and spiral steel pipes have many differences due to different production processes. The difference between straight seam steel pipe and spiral steel pipe. The production process of straight seam welded pipe is relatively simple. The main production processes include high frequency welded thick wall straight seam steel pipe and submerged arc welded thick wall straight seam steel pipe. Thick wall straight seam steel pipe has high production efficiency, low cost, and rapid development. The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe, and the main production process is submerged arc welding. However, compared with the same length of thick-walled straight seam steel pipe, the length of the weld is increased by 30~100%, and the production speed is lower. Therefore, most of the welded pipes with smaller diameters use straight seam welding, and most of the welded pipes with large diameters use spiral welding. T-welding technology is used in the production of large-diameter thick-walled straight-seam steel pipes in the industry, that is, short sections of thick-walled straight-seam steel pipes are butted together to form a length that meets the needs of the project. It is also greatly improved, and the welding residual stress at the T-shaped weld is relatively large, and the weld metal is often in a state of three-way stress, which increases the possibility of cracks.