I. Tube Types
1. Classified by production method
(1) Seamless tubes – hot rolled, cold rolled, cold drawn, extruded and coated tubes
(2) Welded pipes
(a) Divided by process – electric arc welding tube, resistance welding tube (high frequency, low frequency), gas welding tube, furnace welding tube
(b) Divided by weld seam – longitudinal welded tube, spiral welded tube
two . Classified by cross-sectional shape
(1) Simple cross-section steel tube – round steel tube, square steel tube, oval steel tube, triangular steel tube, hexagonal steel tube, diamond-shaped steel tube, octagonal steel tube, round semicircular steel, others
(2) Complex cross-section steel tube – unequal hexagonal steel tube, five-petal plum-shaped steel tube, biconvex steel tube, biconcave steel tube, melon seed-shaped steel tube, tapered steel, corrugated steel tube, supra-crust steel tube, others
3 . Classified by wall thickness
Thin-walled steel pipe, thick-walled steel pipe
4 . Classified by practical use
Pipeline steel pipe, thermal equipment steel pipe, machinery industry steel pipe, petroleum steel pipe, geological drilling, container steel pipe, chemical industry steel pipe, special purpose steel pipe , others
II. Seamless tubes
Seamless steel pipe is a type of long steel with a hollow section and no seams around it.
It has a hollow section and is widely used as a pipeline for transporting fluids, such as oil, natural gas, gas, water and some solid materials.
Compared with solid steel such as round steel, steel tube is lighter in terms of bending and torsional strength.
It is a kind of economical steel section, widely used in manufacturing structural and mechanical parts, such as oil drilling pipes, automobile transmission shafts, bicycle frames and steel scaffolding used in construction, etc.
By manufacturing ring-shaped parts with steel tube, it can improve material utilization, simplify manufacturing processes, saving materials and processing time, such as bearing rings, jack sets, etc., so it has been widely used to manufacture steel tubes.
Steel tubes or a variety of materials indispensable for conventional weapons, gun barrel, gun barrel, etc. are for the manufacture of steel tubes.
Regardless of steel tubes or indispensable materials for various conventional weapons, barrels and pirn must be made of steel tubes.
Steel tubes can be divided into round tubes and special-shaped tubes according to different cross-sectional area shapes.
As the area of the circle is larger under the condition of the same circumference, more fluid can be transported with a circular tube.
However, round tubes also have certain limitations.
For example, under the condition of flat bending, round tubes are not as strong as square and rectangular tubes.
Some agricultural machinery structures, steel and wooden furniture, etc. They often use square and rectangular tubes.
Other cross-sectional shapes are also available depending on the application.
- Structure Seamless Steel Tube (GB/T 8162-2008) is a seamless steel tube used for general and mechanical structures.
- Fluid Conveying Seamless Steel Pipe (GB/T 8163-2008) is a general seamless steel pipe for transporting water, oil, gas and other fluids.
- Low and Medium Pressure Boiler Seamless Steel Pipe (GB 3087-2008) is a hot-rolled and cold-drawn (rolled) seamless steel pipe of high-quality carbon structural steel used for manufacturing boiler pipe. superheated steam, boiling water tube, superheated steam tube for locomotive boiler, large smoke tube, small smoke tube and arc brick tube for various low and medium pressure boiler structures.
- High Pressure Boiler Seamless Steel Pipe (GB 5310-2008) is a high-quality carbon steel, alloy steel and heat-resistant stainless steel pipe, used to manufacture the heating surface of water pipe boiler in high pressure and above.
- Seamless carbon structural steel and alloy steel pipe is for chemical fertilizer equipment and pipelines with working temperature of -40~400℃ and working pressure of 10~30Ma (GB 6479-2013).
- Seamless Steel Pipe for Petroleum Cracking (GB 9948-2013) is applicable to seamless steel pipes for furnace tubes, heat exchangers and pressure pipelines in petroleum refineries.
- Seamless Steel Pipe for Geological Drilling (GB/T 9808-2008) is a steel pipe for core drilling in geological departments, which can be divided into drill pipe, drilling command, core pipe, casing and core pipe. sediments according to the application.
- Geological Drilling Tools (GB/T 16950-2014) specifies the seamless steel pipe used for geological drilling tools.
- Oil drilling pipe (YB 528-65) is a seamless steel pipe used for internal or external thickening at both ends of oil drilling.
Steel pipe is divided into two types: wire and non-woven.
The wire tube is connected with joints and the non-woven tube is connected with tool joints by butt welding method.
- C-Mn Steel Seamless Steel Pipe for Ships (GB/T 5312-2009) is a kind of C-Mn steel seamless steel pipe used in manufacturing Class I and Class II pressure-resistant pipes, boilers and superheaters for ships.
The working temperature of the wall of C-Mn steel seamless pipe is not more than 450 ℃ and that of alloy steel seamless pipe is more than 450 ℃.
- Seamless steel tubes for automobile axle sleeves (GB 3088-82) are hot-rolled seamless steel tubes from high-quality carbon structural steel and alloy structural steel for manufacturing automobile axle sleeves and tubes drive axle.
- High Pressure Seamless Steel Pipes for Diesel Engines (GB/T 3093-2002) are cold drawn seamless steel pipes used to manufacture high pressure pipes for diesel engine injection systems.
- Precision Inner Diameter Seamless Steel Tubes for Hydraulic and Pneumatic Cylinders (GB 8713-88) are cold drawn or cold rolled precision seamless steel tubes with precise inner diameters for manufacturing hydraulic and pneumatic cylinders.
- Cold drawn or cold rolled precision seamless steel tubes (GB/T 3639-2009) are cold drawn or cold rolled precision seamless steel tubes with high dimensional accuracy and good surface finish for mechanical structures and hydraulic equipment.
Using precision seamless steel tubes to manufacture mechanical structures or hydraulic equipment can save a lot of machine time, increase material utilization, and at the same time help improve product quality.
- Seamless Stainless Steel Tubes for Structure (GB/T 14975-2012) is a hot-rolled (extruded, expanded) and cold-drawn (rolled) seamless steel tube made of stainless steel, which is widely used for heavy-duty pipelines corrosion, structural parts and components in chemical, petroleum, textile, medical, food, machinery and other industries.
- Seamless stainless steel pipes for fluid transportation (GB/T 14976-2012) are hot-rolled (extruded, expanded) and cold-drawn (rolled) seamless steel pipes made of stainless steel for fluid transportation.
- Spiral seamless steel pipe is a general term for seamless steel pipes with cross-sectional shapes other than round pipes.
According to different cross-sectional shapes and dimensions, it can be divided into seamless steel pipe with equal wall thickness (codename D), seamless steel pipe with unequal wall thickness (codename BD) and seamless steel pipe seam with a variable diameter (codename BJ).
Seamless profiled tubes are widely used in various structural parts, tools and mechanical parts.
Compared with round pipes, profiled seamless steel pipe generally has higher moment of inertia and cross-sectional modulus, as well as higher bending and torsional strength, which can significantly reduce structural weight and save steel.
Common standard: Cold drawn profiled steel tube (GB/T 3094-2012).
III. Welded Steel Pipe
Welded steel pipe, also known as welded pipe, is made of steel plate or steel strip welded after rolled steel pipe.
Welded steel pipe has a simple production process, high production efficiency, many varieties and specifications, and less equipment, but its overall strength is lower than that of seamless steel pipe.
Since the 1930s, with the rapid development of high-quality continuous strip 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 are increasing and they have replaced seamless steel pipes in more and more fields.
According to the shape of the weld, the welded steel pipe is divided into longitudinal welded pipe and spiral welded pipe.
The longitudinal welded tube has a simple production process, high production efficiency and low cost, which makes it fast.
The strength of spiral welded pipes is generally higher than that of straight seam welded pipes.
A narrower blank can be used to produce welded tubes with larger diameters, and a billet with the same width can be used to produce welded tubes with different tube diameters.
However, compared with the straight seam pipe of the same length, the weld length increases by 30-100% and the production speed is slower.
As a result, longitudinal seam welds are mainly used for smaller diameter welded pipes, while spiral welds are used for larger diameter welded pipes.
- Longitudinal welded steel pipe for low pressure fluid transportation (GB/T 3092-2008) is also known as general welded pipe, commonly known as black pipe.
It is a welded steel pipe for transporting water, gas, air, heating oil and steam and other low pressure fluids and other purposes.
According to the wall thickness, steel pipe is divided into ordinary steel pipe and thickened steel pipe; According to the shape of the connection end, it is divided into non-threaded steel pipe (smooth pipe) and threaded steel pipe.
The specification of the steel pipe is expressed by the nominal diameter (mm), which is the approximate value of the internal diameter.
It is common to express it in inches, such as 11/2.
Welded steel pipes for transporting low pressure fluids are not only used directly to transport fluids, but also as original galvanized welded steel pipes pipes for transporting low pressure fluids.
- Welded steel pipe for low pressure fluid transportation (GB/T 3091-2015), also known as galvanized steel pipe for electric welding, commonly known as white pipe.
It is a hot-dip galvanized welded steel pipe (furnace welded or electric welded) used to transport water, gas, air oil, heating steam, hot water and other generally lower pressure fluids or other purposes.
According to the wall thickness, the steel pipe is divided into ordinary galvanized steel pipe and thick galvanized steel pipe; According to the final shape of the connection, it is divided into unthreaded galvanized steel pipe and threaded galvanized steel pipe.
The specification of the steel pipe is expressed by the nominal diameter (mm), which is the approximate value of the internal diameter.
It is common to express it in inches, such as 11/2.
- Common carbon steel wire casing (GB 3640-88) is a steel tube used for wire protection in industrial and civil construction, machinery and equipment installation and other electrical installation projects.
- Longitudinal welded steel pipe (GB/T 13793-2016) is welded longitudinally parallel to the steel pipe.
It is generally divided into metric welding steel pipe, electric welding thin-wall pipe and transformer oil cooler, etc.
- Spiral seam submerged arc welded steel pipe (SY 5036-83) for transporting fluids under pressure is made from coils of hot-rolled steel strips, which are formed into a spiral at regular temperatures and welded by submerged arc welding of double sided for transporting fluids under pressure. Steel tube with spiral seam.
The steel pipe has strong pressure-bearing capacity and good welding performance.
After multiple inspections and rigorous scientific testing, its use is safe and reliable.
The steel pipe has a large diameter, high transmission efficiency and can save investment in pipeline laying, which is mainly used in pipelines for transporting oil and natural gas.
- Spiral seam high frequency welded steel pipe (SY 5038-83) for conveying fluids under pressure is made from coils of hot-rolled steel strips, which are generally formed into a spiral at temperature.
High frequency welded steel pipe with spiral seam, welded by high frequency overlap welding method to convey pressure fluid.
The steel pipe has strong pressure-bearing ability and good plasticity, which is convenient for welding and processing;
After several rigorous and scientific inspections and tests, its use is safe and reliable.
The steel pipe has a large diameter and high transmission efficiency, which can save investment in pipeline laying.
It is mainly used to install pipelines for transporting oil and natural gas.
- Spiral seam submerged arc welded steel pipe (SY5037-83) for general low-pressure fluid transportation is made from coils of hot-rolled steel strips, which are generally formed into a spiral at hot temperatures.
Submerged arc welded steel pipes made by automatic double-sided submerged arc welding or one-sided welding for general transportation of low pressure fluids such as water, gas, air and steam.
- Spiral seam high frequency welded steel pipe (SY 5039-83) for general transportation of low pressure fluids is made from coils of hot rolled steel strips, which are generally formed into a spiral at temperature.
High-frequency lap welding is used to weld spiral-seam high-frequency welded steel pipes for general low-pressure fluid transportation.
- Spiral Welded Seam Steel Pipe for Pile (SY 5040-83) is made of hot-rolled steel strip coils as empty tubes, which are generally formed into a spiral by double-sided submerged arc welding or high frequency welding .
Steel tubes are used for civil construction for foundation piles, such as docks and bridges.
4. Steel-plastic composite pipe, large-caliber coated steel pipe
The steel-plastic composite pipe is made of hot-dip galvanized steel pipe as the base body, and is made by coating plastic on the inner wall (the outer wall when necessary) by powder fusion spraying technology, with excellent performance.
Compared with galvanized pipe, it has the advantages of anti-corrosion, no rust, no scale, smooth and smooth, clean and non-toxic, and long service life.
According to tests, the service life of steel-plastic composite pipe is more than three times that of galvanized pipe.
Compared with plastic pipes, it has the advantages of high mechanical strength, pressure resistance and heat resistance.
As the substrate is a steel tube, there is no problem of embrittlement or aging.
It can be widely used in tap water, gas, chemical and other fluid transportation and heating projects, which is an upgraded product of galvanized pipe.
Because its installation and use method is basically the same as traditional galvanized pipes, pipe fittings also have exactly the same shape, so they can replace aluminum-plastic composite pipes to play a role in transporting large-caliber tap water .
It is well received by users and has become one of the most competitive new products in the pipeline market.
The coated steel pipe is made through plastic coating on the basis of a large diameter spiral welded pipe and a high frequency welded pipe.
The maximum pipe diameter is 1200 mm.
Various plastic coatings with different properties, such as polyvinyl chloride (PVC), polyethylene (PE) and epoxy resin (EPOZY), can be applied according to different needs.
It has advantages of good adhesion, strong corrosion resistance, resistance to strong acids, strong alkalis and other chemical corrosion, non-toxic, non-corrosive, abrasion resistance, impact resistance and strong permeability resistance.
The surface of the pipeline is smooth and does not stick to any materials, which can reduce resistance during transportation, increase flow rate and transportation efficiency, and reduce pressure loss.
There is no solvent or exudate in the coating, so it will not pollute the transported medium to ensure the purity and hygiene of the fluid.
In the range of -40°C to 80°C, it can be used alternately in hot and cold cycles without aging or cracking, and can be used in aggressive environments such as cold regions.
Large caliber coated steel pipes are widely used in engineering fields such as tap water, natural gas, petroleum, chemicals, medicine, communications, electrical power and oceans, etc.
