• Definition and manufacturing process: Seamless steel pipes are made of solid billets such as round steel and square steel as raw materials, which are perforated to form hollow capillaries after heating, and then processed through rolling, sizing, straightening and other processes. The production process of hot-rolled seamless steel pipe is as follows: round pipe billet heating→ perforation→ three-roll oblique rolling, continuous rolling or extrusion→ detubing→ sizing→ cooling→ straightening→ water pressure test→ marking→ warehousing; Cold-drawn seamless steel pipes are made on the basis of hot rolling, through heading→ annealing→ pickling→ oiling→ multiple rounds of cold drawing→ heat treatment→ straightening→ water pressure test→ marking→ warehousing and other processes.

• Classification: According to the material, it can be divided into carbon steel seamless steel pipe, alloy steel seamless steel pipe, stainless steel seamless steel pipe, etc.; According to the use, it can be divided into structural seamless steel pipes, boiler pipes, oil pipeline pipes, etc.; According to the manufacturing process, it can be divided into hot-rolled seamless steel pipes, cold-drawn seamless steel pipes, etc.

• Features: Seamless steel pipe has high strength and good pressure resistance, suitable for withstanding large pressure; The material structure is relatively uniform, which can ensure that the force distribution in the work is more reasonable. Good corrosion resistance, especially stainless steel seamless steel pipes, suitable for use in harsh environments; There are no welded seams, which is more reliable than welded steel pipes and has a long service life.

• Specifications: The specifications of seamless steel pipes are expressed by the outer diameter of the pipe multiplied by the wall thickness, and its length is usually 3000-12000mm for hot-rolled pipes and 2000-10500mm for cold-rolled pipes.

• Implementation standards: Common ones include GB/T 8162 structural seamless steel pipe, GB/T 8163 fluid seamless steel pipe, GB/T 5310 high-pressure boiler pipe, etc.

• Application fields: widely used in petroleum, chemical, electric power, machinery manufacturing and other fields. For example, in the oil and gas industry, it is used for oil and gas transmission pipelines, oil drilling pipes, etc.; In the power industry, it is used for boiler tubes, steam pipelines, etc.; In the chemical industry, it is used for pipes for transporting corrosive fluids, etc.