1.Classification by outer diameter
Capillary tubes: Below 10 mm
Small-diameter pipes: 10.3 (1/8") to 102 (3"/8") mm
Medium-diameter pipes: 114 (4") to 508 (20") or 660 (20") mm
Large-diameter pipes: Over 508 (or 660) mm
2.Classification by the ratio of pipe diameter to wall thickness
Extra-thick-walled pipes: Diameter/Wall thickness < 5.5 or Wall thickness/Diameter > 0.18
Thick-walled pipes: Diameter/Wall thickness between 5.5 and 10.0 or Wall thickness/Diameter between 0.18 and 0.10
Standard pipes: Diameter/Wall thickness between 9.1 and 20 or Wall thickness/Diameter between 0.12 and 0.05
Thin-walled pipes: Diameter/Wall thickness between 20.1 and 50 or Wall thickness/Diameter between 0.05 and 0.02
Extra-thin-walled pipes: Diameter/Wall thickness > 50 or Wall thickness/Diameter < 0.02
3.Classification by application
Transmission pipes: Used for pipeline transportation of water, gas, oil, natural gas, and solids.
Structural pipes: Utilized in construction, various steel structures, and furniture manufacturing.
Machinery manufacturing pipes: Employed in automobile, agricultural machinery, and machine manufacturing.
Boiler and heat exchanger pipes: Include boiler water pipes, smoke pipes, heater and preheater pipes, heat exchanger pipes in the chemical and petrochemical industries, as well as pipes for refrigeration, condensation, and other low-temperature applications.
Oil drilling and production pipes: Used for oil drilling rods, casing pipes, etc.
