(1) Importance of structure
For important structures such as heavy industrial building structures, long-span structures, high-rise or super-high-rise civil building structures or structures, the use of high-quality seamless steel pipes should be considered. For general industrial and civil building structures, ordinary high-quality seamless steel pipes can be selected according to the nature of the work.
(2) Load condition
For structures directly bearing dynamic loads and structures in strong earthquake areas, carbon steel seamless steel pipes with good comprehensive properties should be selected; for structures generally bearing static loads, lower-priced seamless steel pipes can be used.
(3) Connection method
Welding defects such as welding deformation and welding stress will occur during the welding process, which may cause structural cracks or brittle fractures. Therefore, the material requirements for welded structures should be more stringent.
(4) Temperature and environment where the structure is located
Seamless steel pipes are easy to become brittle at low temperatures. Therefore, structures working under low temperature conditions, especially welded structures, should use killed steel with good resistance to low temperature brittle fracture. In addition, the Taiyuan seamless steel pipe in the open-air structure is easy to age, and the seamless steel pipe containing harmful media is prone to corrosion, fatigue and fracture. Different materials should also have different options.
(5) Thickness of seamless steel pipe
The thin-walled seamless steel pipe is rolled more frequently, and the rolling compression ratio is large, and the thick seamless steel pipe has a small compression ratio. Therefore, the large-thickness precision steel pipe not only has low strength, but also has poor plasticity, impact toughness and welding performance. Therefore, for the welded structure with larger thickness, the seamless steel pipe with better material should be selected.
Seamless carbon steel pipe is a long steel strip with a hollow section, which is widely used as a pipeline for transporting fluids, such as pipelines for transporting oil, natural gas, natural gas, water and certain solid materials. Compared with solid steel such as round steel, steel pipe has the same bending and torsional strength and lighter weight. It is an economical section steel and is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile transmission shafts, bicycle frames and steel scaffolding for construction.