Welded steel pipe for low pressure liquid delivery (GB/T3092-1993) also called general hanguan, commonly known as the clarinet. It is a kind of welded steel pipe for conveying water, gas, air, oil and heating steam and other general low pressure fluids and other purposes. The thickness of the steel pipe is divided into ordinary steel pipe and thickened steel pipe. The pipe end is divided into non threaded steel pipe (light pipe) and steel pipe with screw thread. Specifications of steel pipe with nominal diameter (mm), the nominal diameter is the approximate value of the inner diameter. Commonly used in inches, such as 11/2, etc.. In addition to being used directly for conveying fluid, the welded pipe for low pressure fluid conveying is also used as the main pipe of galvanized steel pipe for low pressure fluid transportation.

2 low pressure fluid transmission galvanized steel pipe (GB/T3091-1993), also known as galvanized steel pipe, commonly known as white tube. Is used for conveying water, gas, air, oil and heating steam, warm water generally low pressure fluid or other use of hot dip galvanized welded steel pipe (furnace welding or welding). The thickness of steel pipe joint is divided into ordinary galvanized steel pipe and thickened galvanized steel pipe. Specifications of steel pipe with nominal diameter (mm), the nominal diameter is the approximate value of the inner diameter. Commonly used in inches, such as 11/2, etc..

3 ordinary carbon steel wire casing (GB3640-88) is a steel pipe protecting wire for industrial and civil construction, installation of machinery and equipment in electrical installation engineering.

4 straight seam welded steel pipe (YB242-63) is parallel with steel pipe welding longitudinal welded pipe. Usually divided into metric welded steel pipe, welded thin-walled tube, transformer cooling tubing, etc.