Introduction to Practical Knowledge of Pipes (Part 1)

Classification of pipes

1. Classification by production method

(1) Seamless tube-hot rolled tube, cold tube, cold drawn tube, extruded tube, jacking tube

(2) Welded pipe

(A) According to the process-arc welding pipe, resistance welding pipe (high frequency, low frequency), gas welding pipe, furnace welding pipe

(B) According to the welding, seam-straight seam welded pipe, spiral welded pipe

2. Classification by cross-sectional shape

(1) Simple cross-section steel tubes-round steel tubes, square steel tubes, oval steel tubes, triangular steel tubes, hexagonal steel tubes, diamond-shaped steel tubes, octagonal steel tubes, semi-circular steel tubes, and others.

(2) Complex cross-section steel tubes-unequal hexagonal steel tubes, five-petal plum-shaped steel tubes, double convex steel tubes, double concave steel tubes, melon-shaped steel tubes, conical steel tubes, corrugated steel tubes, case steel tubes, and others.

3. Classification by wall thickness-thin-walled steel pipe, thick-walled steel pipe

4. Classification according to usage-steel pipes for pipelines, steel pipes for thermal equipment, steel pipes for machinery industry, petroleum, geological drilling steel pipes, container steel pipes, chemical industry steel pipes, special-purpose steel pipes, and others.

Welded Steel Pipe

Welded steel pipe

Welded steel pipe, also known as welded pipe, is a steel pipe that is made by welding a steel plate or steel strip after crimping. Welded steel pipe production process is simple, high production efficiency, many varieties, and specifications. Since the 1930s, with the rapid development of high-quality strip continuous rolling production and the advancement of welding and inspection technology, the quality of welds has been continuously improved, the variety and specifications of welded steel pipes have been increasing, and have replaced Seam steel pipe. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes in the form of welds.

Straight seam welded pipe production process is simple, high production efficiency, low cost and rapid development. The strength of spiral welded pipe is generally higher than that of straight seam welded pipe. It is possible to produce a welded pipe with a larger diameter from a narrower blank, and to produce a welded pipe with a different diameter from a blank of the same width. However, compared with the straight seam pipe of the same length, the length of the weld seam is increased by 30-100%, and the production speed is lower.

1. Straight seam welded steel pipe for low-pressure fluid transportation (GB/T 3092-2008) is also called a general welded pipe, commonly known as black pipe. It is a welded steel pipe used for conveying water, gas, air, oil, and heating steam and other generally low-pressure fluids and other uses. The wall thickness of the steel pipe is divided into ordinary steel pipe and thickened steel pipe; the form of the pipe end is divided into a non-threaded steel pipe (light pipe) and threaded steel pipe. The specification of the steel pipe is expressed by the nominal diameter (mm), which is an approximate value of the inner diameter. It is customary to use inches, such as 11/2. In addition to being directly used to transport fluids, welded steel pipes for low-pressure fluid transportation are also used as raw pipes for galvanized welded steel pipes for low-pressure fluid transportation.

2. Low Pressure fluid pipe (GB/T 3091-2015) is also called galvanized welded steel pipe, commonly known as a white pipe. It is a hot-dip galvanized welding (furnace welding or electric welding) steel pipe used for conveying water, gas, air oil, heating steam, warm water, and other generally low-pressure fluids or other purposes. The wall thickness of the steel pipe is divided into ordinary galvanized steel pipe and thickened galvanized steel pipe; the form of the pipe end is divided into non-threaded galvanized steel pipe and threaded galvanized steel pipe. The specification of the steel pipe is expressed by the nominal diameter (mm), which is an approximate value of the inner diameter. It is customary to use inches, such as 11/2.

3. Ordinary carbon steel wire bushing (GB 3640-88) is a steel pipe used to protect wires in electrical installation projects such as industrial and civil buildings, installation of machinery and equipment.

4. Straight seam welded steel pipe (GB/T 13793-2016) is a steel pipe with a weld seam parallel to the longitudinal direction of the steel pipe. Usually divided into metric welded steel pipes, welded thin-walled pipes, transformer cooling oil pipes and so on.

5. Spiral seam submerged arc welded steel pipe for pressure fluid transportation (SY 5036-83) is made of hot rolled steel coil as the tube blank, which is often hot spiral formed and welded by double side submerged arc welding method for pressure fluid transportation Spiral seam steel pipe. The steel pipe has strong pressure bearing capacity and good welding performance. After various strict scientific inspections and tests, it is safe and reliable to use. The steel pipe has a large diameter, high transmission efficiency, and can save investment in laying pipelines. Mainly used to transport oil and natural gas pipelines.

6. Spiral seam high-frequency welded steel pipe for pressure fluid transportation (SY 5038-83) is made of hot-rolled steel coil as the tube blank, which is often hot spiral formed and welded by high-frequency lap welding method for pressure fluid Conveyed spiral seam high-frequency welded steel pipe. The steel pipe has strong pressure bearing capacity and good plasticity, which is convenient for welding and processing; after various strict and scientific inspections and tests, it is safe and reliable to use, the steel pipe has a large diameter, high transmission efficiency, and can save investment in laying pipelines. It is mainly used for laying pipelines for oil and natural gas.

7. The spiral seam submerged arc welding steel pipe (SY5037-83) for general low-pressure fluid transportation is made of hot-rolled steel coil as the tube blank, which is often hot spiral formed, and is made by double-sided automatic submerged arc welding or single-sided welding method. Submerged arc welded steel pipes for general low-pressure fluid transportation such as water, gas, air, and steam.

8. Spiral seam high-frequency welded steel pipe for general low-pressure fluid transportation (SY 5039-83) uses hot-rolled steel strip coil as the tube blank, which is often spiral-formed and welded by high-frequency lap welding for general low-pressure fluid transportation. Spiral seam high-frequency welded steel pipe.

9. Spiral welded steel pipe for piles (SY 5040-83) is made of hot-rolled steel coil as the tube blank, which is often spirally formed by double-sided submerged arc welding or high-frequency welding. Steel pipes for foundation piles of wharves and bridges.