Welded steel pipe, also called welded pipe, is a steel pipe made of steel plates or strips that are welded after being curled and formed. The length is usually 6 meters. The production process of welded steel pipes is simple, the production efficiency is high, there are many varieties and specifications, and the equipment investment is low, but the general strength is lower than that of seamless steel pipes.
product description
Since the 1930s, with the rapid development of continuous rolling production of high-quality strip steel and the advancement of welding and inspection technology, the quality of welds has been continuously improved, and the varieties and specifications of welded steel pipes have been increasing day by day, and they have replaced non-woven steel pipes in more and more fields. Sewing steel pipe. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes according to the form of the weld. Classification by production method: Process classification - arc welded pipe, resistance welded pipe, (high frequency, low frequency) gas welded pipe, furnace welded pipe.
Smaller diameter welded pipes use straight seam welding, while large diameter welded pipes mostly use spiral welding; according to the shape of the end of the steel pipe, it is divided into round welded pipes and special-shaped (square, rectangular, etc.) welded pipes; according to different materials and uses, it is divided into mining fluids Welded steel pipes for transportation, galvanized welded steel pipes for low-pressure fluid transportation, electric welded steel pipes for belt conveyor rollers, etc. According to the specification and size table in the current national standard, sort by outer diameter*wall thickness from small to large.
Product Standards
Common materials for welded pipes are: Q235A, Q235C, Q235B, 16Mn, 20#, Q345, L245, L290, X42, X46, X60, X80, 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.
The blanks used in welded steel pipes are steel plates or strips. Due to their different welding processes, they are divided into furnace welded pipes, electric welded (resistance welded) pipes and automatic arc welded pipes. Because of their different welding forms, they are divided into two types: straight seam welded pipes and spiral welded pipes. Because of their end shapes, they are divided into round welded pipes and special-shaped (square, flat, etc.) welded pipes. Welded pipes are divided into the following varieties due to their different materials and uses:
GB/T3091-2008 (Welded steel pipe for low-pressure fluid transportation): Mainly used to transport water, gas, air, oil, heating hot water or steam and other general lower pressure fluids and other pipes. Its representative material is: Q235A grade steel.
GB/T14291-2006 (Welded steel pipe for mining fluid transportation): Mainly used for straight seam welded steel pipes for mine air pressure, drainage, and shaft gas discharge. Its representative materials are Q235A and B grade steel.
GB/T12770-2002 (Stainless steel welded steel pipes for mechanical structures): Mainly used for machinery, automobiles, bicycles, furniture, hotel and restaurant decoration and other mechanical components and structural parts. Its representative materials include 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.
GB/T12771-1991 (Stainless steel welded steel pipe for fluid transportation): Mainly used to transport low-pressure corrosive media. Representative materials are 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc.
In addition, welded stainless steel pipes for decoration (GB/T 18705-2002), stainless steel welded pipes for building decoration (JG/T 3030-1995), and welded steel pipes for heat exchangers (YB4103-2000).
Production Process
The production process of straight seam welded pipe is simple, the production efficiency is high, the cost is low, and the development is rapid. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. Welded pipes with larger diameters can be produced from narrower billets, and welded pipes with different diameters can also be produced from billets of the same width. However, compared with straight seam pipes of the same length, the weld length is increased by 30~100%, and the production speed is lower.
Large diameter or thicker welded pipes are generally made directly from steel blanks, while small welded pipes and thin-walled welded pipes only need to be directly welded through steel strips. Then simply polish and brush it.
Supplement: The welded pipe is welded with strip steel, so its original status is not as high as the seamless pipe.
Welded pipe process flow
Raw material uncoiling - flattening - end shearing and welding - looper - forming - welding - internal and external weld bead removal - pre-correction - induction heat treatment - sizing and straightening - eddy current testing - cutting off - hydraulic inspection - pickling - final inspection (Strictly controlled)-packaging-shipping.
Features
The production process of straight seam welded pipe is simple, the production efficiency is high, the cost is low, and the development is rapid. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. Welded pipes with larger diameters can be produced from narrower billets, and welded pipes with different diameters can also be produced from billets of the same width. However, compared with straight seam pipes of the same length, the weld length is increased by 30~100%, and the production speed is lower.
Application scope
Products are widely used in water supply projects, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, and urban construction. They are one of the twenty key products developed in my country.
For liquid transportation: water supply and drainage. For gas transportation: coal gas, steam, liquefied petroleum gas.
For structural purposes: piling pipes, bridges; pipes for docks, roads, building structures, etc. [1]
Category Editor Broadcast
Classified by use
It is further divided into general welded pipes, galvanized welded pipes, oxygen blown welded pipes, wire casings, metric welded pipes, roller pipes, deep well pump pipes, automotive pipes, transformer pipes, welded thin-walled pipes, welded special-shaped pipes, scaffolding pipes and spiral welded pipes .
General welded pipe: General welded pipe is used to transport low-pressure fluid. Made of Q195A, Q215A, Q235A steel. It can also be made of other mild steels that are easily weldable. Steel pipes are subject to hydraulic pressure, bending, flattening and other experiments, and have certain requirements for surface quality. The delivery length is usually 4-10m, and delivery of fixed length (or multiple lengths) is often required. The specifications of welded pipes are expressed in nominal diameter (millimeters or inches). The nominal diameter is different from the actual. According to the specified wall thickness, there are two kinds of welded pipes: ordinary steel pipes and thickened steel pipes.
Galvanized steel pipe: In order to improve the corrosion resistance of steel pipes, general steel pipes (black pipes) are galvanized. Galvanized steel pipes are divided into two types: hot-dip galvanizing and electro-galvanizing. Hot-dip galvanizing has a thick zinc layer and electro-galvanizing has a low cost.
Oxygen blowing welded pipe: used as oxygen blowing pipe for steelmaking. Generally, small diameter welded steel pipe is used, with eight specifications ranging from 3/8 inch to 2 inch. Made of 08, 10, 15, 20 or Q195-Q235 steel strip. In order to prevent corrosion, some are aluminized.
Wire casing: It is an ordinary carbon steel electric welded steel pipe. It is used in concrete and various structural power distribution projects. The commonly used nominal diameter is from 13-76mm. The wire sleeve has a thin wall and is mostly used after being coated or galvanized, requiring a cold bending test.
Metric welded pipe: specifications are used in the form of seamless pipes, welded steel pipes expressed in outer diameter * wall thickness mm, with tropical or cold zone welding of ordinary carbon steel, high-quality carbon steel or general low alloy steel, or with tropical welding Then it is made by cold drawing method. Metric welded pipes are divided into general-purpose and thin-walled pipes. They are generally used as structural parts, such as transmission shafts, or to transport fluids. Thin-walled pipes are used to produce furniture, lamps, etc. The strength and bending test of the steel pipe must be ensured.
Roller tube: used for belt conveyor roller electric welded steel pipe, generally made of Q215, Q235A, B steel and 20 steel, with a diameter of 63.5-219.0mm. There are certain requirements for the curvature of the pipe, the end face to be perpendicular to the center line, and the ovality. Generally, water pressure and flattening tests are conducted.
Transformer tube: used to manufacture transformer radiator tubes and other heat exchangers. It is made of ordinary carbon steel and requires flattening, flaring, bending and hydraulic testing. Steel pipes are delivered in fixed lengths or multiple lengths, and there are certain requirements for the bending of the steel pipes.
Special-shaped pipes: square pipes, rectangular pipes, hat-shaped pipes, hollow rubber steel pipes for doors and windows welded from ordinary carbon structural steel and 16Mn and other steel strips. They are mainly used as agricultural machinery components, steel windows and doors, etc.
Electrically welded thin-walled tubes: mainly used to make furniture, toys, lamps, etc. In recent years, thin-walled tubes made of stainless steel strips have been widely used in high-end furniture, decorations, fences, etc.
Spiral welded pipe: It is made by rolling low-carbon carbon structural steel or low-alloy structural steel strips into pipe blanks at a certain spiral angle (called forming angle), and then welding the pipe seams. It can be made of narrower pipes. Strip steel produces large diameter steel pipes. Spiral welded pipes are mainly used for oil and natural gas transmission pipelines, and their specifications are expressed by outer diameter * wall thickness. Spiral welded pipes are either single-sided or double-sided. Welded pipes should ensure that the hydraulic pressure test, tensile strength and cold bending performance of the weld meet the regulations.
Classification by production method
(1) According to process - arc welded pipe, resistance welded pipe (high frequency, low frequency), gas welded pipe, furnace welded pipe.
(2) According to the welding seam - straight seam welded pipe, spiral welded pipe.
Classification by cross-sectional shape
(1) Simple cross-section steel pipes - round steel pipes, square steel pipes, oval steel pipes, triangular steel pipes, hexagonal steel pipes, rhombus steel pipes, octagonal steel pipes, semi-circular steel pipes, and others.
(2) Complex cross-section steel pipes - unequal hexagonal steel pipes, five-petal plum blossom-shaped steel pipes, double-convex steel pipes, double-concave steel pipes, melon-shaped steel pipes, conical steel pipes, corrugated steel pipes, watch case steel pipes, and others.
Classified by wall thickness
Thin-walled steel pipes, thick-walled steel pipes.
Classification by end shape
Divided into round welded pipes and special-shaped (square, flat, etc.) welded pipes.
Classification supplement
1. Ordinary carbon steel wire casing (GB/T3640-88) is a steel pipe used to protect wires in electrical installation projects such as industrial and civil buildings and installation of machinery and equipment.
2. Straight seam electric welded steel pipe (YB242-63) is a steel pipe with the weld seam and the steel pipe longitudinally parallel. Usually divided into metric electric welded steel pipes, electric welded thin-walled pipes, transformer cooling oil pipes, etc.
3. Spiral submerged arc welded steel pipe (SY5036-83) for pressure-bearing fluid transportation is made of hot-rolled steel strip coils as pipe blanks, spirally formed at constant temperature, and welded by double-sided submerged arc welding. It is used for pressure-bearing fluid transportation. Spiral seam steel pipe. Steel pipes have strong pressure-bearing capacity and good welding performance. They have undergone various rigorous scientific inspections and tests and are safe and reliable to use. The steel pipe has a large diameter, high transportation efficiency, and can save investment in laying pipelines. Mainly used for pipelines transporting oil and natural gas.
4. Spiral seam high-frequency welded steel pipe (SY5038-83) for pressure-bearing fluid transportation is made of hot-rolled steel strip coils as pipe blanks, spirally formed at constant temperature, and welded by high-frequency lap welding method. It is used for pressure-bearing fluid transportation. Spiral seam high frequency welded steel pipe. Steel pipes have strong pressure-bearing capacity, good plasticity, and are easy to weld and process. After various strict and scientific inspections and tests, they are safe and reliable to use. The steel pipes have large diameters, high transportation efficiency, and can save investment in laying pipelines. Mainly used for laying pipelines transporting oil, natural gas, etc.
5. Generally, spiral seam submerged arc welded steel pipes for low-pressure fluid transportation (SY/T5037-2000) are made of hot-rolled steel strip coils as pipe blanks, which are often heated and spirally formed, and are made by double-sided automatic submerged arc welding or single-sided welding. Submerged arc welded steel pipes are used for transporting general low-pressure fluids such as water, gas, air and steam.
6. Spiral seam high-frequency welded steel pipe (SY5039-83) for general low-pressure fluid transportation is made of hot-rolled steel strip coils as pipe blanks, spirally formed at constant temperature, and welded by high-frequency lap welding. It is used for general low-pressure fluid transportation. Seam high frequency welded steel pipe.
7. Spiral welded steel pipe for piles (SY5040-83) is made of hot-rolled steel strip coils as pipe blanks, spirally formed at constant temperature, and made by double-sided submerged arc welding or high-frequency welding. It is used for civil construction structures and docks. , bridges and other foundation piles.
Zhengde Welded steel pipe, also known as welded pipe, is a steel pipe made by welding steel plates or strips after being rolled and formed. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes according to the form of welds. Classified by production method: arc welded pipe, resistance welded pipe, (high-frequency, low-frequency) gas welded pipe, furnace welded pipe. The production process of straight seam welded pipe is simple, with high production efficiency, low cost, and rapid development. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. Narrow billets can be used to produce larger diameter welded pipes, and billets of the same width can also be used to produce welded pipes of different diameters. However, compared to straight seam pipes of the same length, the weld length increases by 30-100% and the production speed is lower. Thick wall coil products include: large coil, large diameter thick wall coil, various materials thick wall coil, hot rolled thick wall coil, cold rolled thick wall coil, etc.
All welded pipes can be made into galvanized welded pipes, which can be found through product consultation on the homepage.
| DN |
Welded steel pipe (ordinary) |
Welded steel pipe (thickened) |
Seamless steel pipe (hot rolled) |
Spiral welded steel pipe |
| pg≤1.0Mpa |
pg≤1.6Mpa |
pg≤2.5Mpa |
pg≤1.6Mpa |
| |
D×∮ |
(Kg/m) |
D×∮ |
(Kg/m) |
D×∮ |
(Kg/m) |
D×∮ |
(Kg/m) |
| DN15 |
21.3*2.75 |
1.25 |
21.3*3.25 |
1.44 |
---- |
---- |
---- |
---- |
| DN20 |
26.8*2.75 |
1.63 |
26.8*3.5 |
2.01 |
---- |
---- |
---- |
---- |
| DN25 |
33.5*3.25 |
2.42 |
33.5*4 |
2.91 |
32*3.5 |
2.46 |
---- |
---- |
| DN32 |
42.3*3.25 |
3.13 |
42.3*4 |
3.77 |
38*3.5 |
2.98 |
---- |
---- |
| DN40 |
48*3.5 |
3.84 |
48*4.25 |
4.58 |
45*3.5 |
3.58 |
---- |
---- |
| DN50 |
60*3.5 |
4.88 |
60*4.5 |
6.16 |
57*3.5 |
4.62 |
---- |
---- |
| DN65 |
75.5*3.75 |
6.64 |
75.5*4.5 |
7.88 |
73*4 |
6.81 |
---- |
---- |
| DN80 |
88.5*4 |
8.34 |
88.5*4.75 |
9.81 |
89*4 |
8.38 |
---- |
---- |
| DN100 |
114*4 |
10.85 |
114*5 |
13.44 |
108*4 |
10.26 |
---- |
---- |
| DN125 |
140*4.5 |
15.04 |
140*4.5 |
18.24 |
133*4 |
12.72 |
---- |
---- |
| DN150 |
165*4.5 |
17.81 |
165*5.5 |
21.63 |
159*4.5 |
17.14 |
168*5 |
20.1 |
| DN200 |
---- |
---- |
---- |
---- |
219*6 |
31.52 |
219*5 |
31.52 |
| DN250 |
---- |
---- |
---- |
---- |
273*8 |
52.28 |
273*7 |
45.92 |
| DN300 |
---- |
---- |
---- |
---- |
325*8 |
62.54 |
325*7 |
54.9 |
| DN350 |
---- |
---- |
---- |
---- |
377*9 |
81.67 |
377*7 |
63.87 |
| DN400 |
---- |
---- |
---- |
---- |
426*9 |
92.55 |
426*7 |
72.33 |
| DN450 |
---- |
---- |
---- |
---- |
480*9 |
104.53 |
478*7 |
81.31 |
| DN500 |
---- |
---- |
---- |
---- |
530*9 |
115.62 |
529*7 |
90.11 |
| DN600 |
---- |
---- |
---- |
---- |
630*9 |
137.82 |
630*7 |
107.5 |
Our Advantages
Longitudinally welded pipes
The production process of straight seam welded pipe is simple, with high production efficiency, low cost, and rapid development. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. Narrow billets can be used to produce larger diameter welded pipes, and billets of the same width can also be used to produce welded pipes of different diameters. However, compared to straight seam pipes of the same length, the weld length increases by 30-100% and the production speed is lower. Therefore, smaller diameter welded pipes mostly use straight seam welding, while larger diameter welded pipes mostly use spiral welding.Straight seam welded pipes are divided into longitudinal submerged arc welding (LSAW) and electric resistance welding (ERW).
Square tube
Square tube is a term for square and rectangular pipes, which refers to steel pipes with equal sides. It is made of rolled steel strip after process treatment. Generally, the strip steel is unpacked, flattened, curled, and welded to form a circular tube, which is then rolled into a square tube and cut to the required length. Also known as square and rectangular cold formed hollow steel, abbreviated as square tube and rectangular tube, with codes F and J respectively. The allowable deviation of the wall thickness of rectangular pipes shall not exceed 10% of the nominal wall thickness when the wall thickness is not greater than 10mm, and shall not exceed 8% of the wall thickness when the wall thickness is greater than 10mm, except for the wall thickness of corner and weld areas. The typical delivery length of square tube is 4000mm-12000mm, with the majority being 6000mm and 12000mm.
SSAW spiral welded pipe
Spiral welded steel pipes refer to steel pipes with joints on the surface that are formed by bending and deforming steel strips or steel plates into circular or square shapes and then welding them. According to different welding methods, it can be divided into arc welded pipes, high-frequency or low-frequency resistance welded pipes, gas welded pipes, furnace welded pipes, Bondi pipes, etc. According to the shape of the weld seam, it can be divided into straight seam welded pipes and spiral welded pipes. Welded steel pipes are used in petroleum drilling and mechanical manufacturing industries. Furnace welded pipes can be used as water and gas pipes, and large-diameter straight seam welded pipes can be used for high-pressure oil and gas transportation, etc; Spiral welded pipes are used for oil and gas transportation, pipe piles, bridge piers, etc. Welded steel pipes have lower costs and higher production efficiency than seamless steel pipes.
Thick walled coiled tube
Thick walled coiled pipes, as the name suggests, are rolled out of steel plates. T-shaped welded pipes are the main type of coiled pipes, while spiral pipes and straight seam pipes are not strictly speaking coiled pipes. Before rolling pipes, it is necessary to familiarize oneself with technical requirements such as drawings, process material performance, etc., select an appropriate rolling machine, and determine whether to roll cold, warm, or hot. The specification and model range of hot-rolled thick walled steel pipes: diameter 400 to 3000mm, wall thickness 4 to 300mm, and length produced according to user needs. Products include: large coil tubes, large diameter thick wall coils, thick wall coils of various materials, hot rolled thick wall coils, cold rolled thick wall coils, etc.
Quality first: production and inspection in strict accordance with production standards;
Price advantage: discounts based on real market prices;
Transaction security: There will be no loss of customer funds;
After-sales guarantee: the customer's problem is our problem;
Long-term cooperation: quality assurance, price advantage, sincere service can last for a long time.
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Packaging & Shipping
Company Profile
Shandong Zhengde Metal Manufacturing Co., Ltd. is a production and sales company integrating hot-rolled steel coils, cold-rolled steel coils, galvanized steel coils, color-coated steel coils, section steel, steel pipes, steel wires, metal mesh, stainless steel, aluminum, copper and other metal products integrated large enterprises. Five production and sales bases have been formed in Binzhou, Liaocheng, Wuxi, Tianjin, Jinan and Tai'an, with more than 100 production lines, 4 nationally recognized laboratories, 2 technical engineering centers, and 5 enterprise technology centers. Products are exported to more than 50 countries and regions such as North America, South America, Europe, Africa, Oceania, Middle East, and Southeast Asia.
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