There are significant differences between seamless steel pipes and welded pipes in many aspects, and these differences determine the basis of their respective applications. The following is a detailed explanation of the differences and uses of seamless steel pipes and welded pipes:

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Molding process

Seamless steel pipe: It is made by perforating a solid tube blank or steel ingot and then processing it through hot rolling, cold rolling or cold drawing. During the entire process, no welds are produced inside the steel pipe, hence the name "seamless".

Welded pipe: The steel plate or steel strip is bent into a tube shape, and then the seams are welded through a welding process. Common welding methods include high-frequency welding and spiral welding.

Appearance features

1. Seamless steel pipe: Smooth surface, no welds, good integrity and beautiful appearance.

2. Welded pipe: Since it is made by welding, the weld seam can be clearly seen on its surface. However, with the advancement of technology, some welded steel pipes will be welded to make the welds less obvious.

Performance characteristics

1. Seamless steel pipe: Since there are no welds, its pressure-bearing capacity is usually high and it is suitable for harsh environments such as high pressure and high temperature. At the same time, the precision and smoothness of seamless steel pipes are also relatively high, making them suitable for occasions that require high performance of steel pipes.

2. Welded pipe: Although the pressure-bearing capacity is lower than that of seamless steel pipe, the cost is lower and it is easy to process and install.

Price

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1. Seamless steel pipe: Due to the complex manufacturing process and superior performance, its price is usually higher than that of welded steel pipe. However, the specific price will also be affected by market supply and demand, raw material price fluctuations and other factors.

2. Welded pipe: Lower cost, suitable for high-volume, low-cost application scenarios.

Use

1. Seamless steel pipe

Seamless steel pipes are mainly used in petroleum geological drilling pipes, petrochemical cracking pipes, boiler pipes, bearing pipes and high-precision structural steel pipes for automobiles, tractors, and aviation. In addition, it is also widely used in petroleum, chemical industry, electric power, nuclear energy and other fields, especially in situations where it needs to withstand harsh environments such as high pressure, high temperature and corrosion.

Seamless steel pipes are also commonly used to manufacture structural parts and mechanical parts, such as oil drill pipes, automobile drive shafts, bicycle frames, and steel scaffolding used in construction. Because of its hollow cross-section, it is widely used as a pipeline for transporting fluids, such as pipelines for transporting oil, natural gas, coal gas, water and certain solid materials.

2. Welded pipe

Welded pipes are widely used in water supply engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, urban construction and other fields. In the field of construction, welded pipes are often used in steel structure frames, supports, and protective railings; in the field of pipeline transportation, welded pipes are used to transport fluid media such as water, gas, and oil.

Welded pipes are also used in machinery manufacturing, automobile manufacturing, railways and aerospace. In these fields, welded pipes are widely used due to their high strength, good toughness, corrosion resistance, and easy processing.

Summarize

In summary, seamless steel pipes have no welds, high pressure resistance, and high precision, and are used in high-pressure and high-temperature situations; welded pipes have welds, are low-cost, and easy to process, and are used in low-cost, high-volume applications. There are obvious differences between seamless steel pipes and welded pipes in terms of forming process, appearance characteristics, performance characteristics, application fields and price. When choosing steel pipes, you need to choose the appropriate type according to the specific use environment and requirements.

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LSAW Welded Steel Pipe: Features and Manufacturing Processes

What is LSAW pipe means
LSAW (Longitudinal double submerge arc welding) carbon steel pipe is a type of SAW pipe made of steel plates that were hot rolled by JCOE or UOE forming technology. JCOE technology represents the shaping and forming processes involved during manufacturing as well as the inner and outer welding and cold expansion carried out after welding.


When compared to UOE LSAW steel pipes, LSAW pipe manufacturers in China can produce more sizes as thus: OD 406 mm ' mm, thickness 6.35 mm ' 60 mm, pipe length 2 m ' 18 m with the LSAW pipe having superiority.


Octal offers LSAW steel pipe with high quality and competitive prices.


LSAW steel pipe features
Features:


-Large diameter steel pipes
-Thick walls
-High-Pressure resistance
-Low-temperature resistance


Tests:


-Chemical Component Analysis
-Mechanical Properties ' Elongation, Yield Strength, Ultimate Tensile Strength
-Technical Properties ' DWT Test, Impact Test, Blow Test, Flattening Test
-X-ray Test
-Exterior Size Inspection
-Hydrostatic Test
-UT Test


How to use LSAW welded steel pipe for pipelines
The basic metal and welding metal have been tested according to the specification of the pipe API SPEC 5L, DIN, EN, ASTM, GOST standard and other standards.


Also, LSAW pipe can be welded with flanges, lifting eyes and other parts depending on clients' requirements.


LSAW pipe are used for conveying fluids like oil, gas and water transportation as well as used for seashore projects and ground constructions. These products are manufactured in China and are exported to other countries like United States of America, Canada, India, Pakistan, Africa, etc.


LSAW steel pipe manufacturing process
The LSAW large diameter steel pipe manufacturing process is explained in the steps below:


1. Plate Probe: This is used for manufacturing the large diameter LSAW joints right after it enters the production line which is the initial full-board ultrasonic testing.
2. Milling: The machine used for milling does this operation through two-edged milling plate to meet the requirements of the plate width and the sides parallel to the shape and degree.
3. Pre-curved side: This side is achieved by using a pre-bending machine on the pre-bending plate edge. The plate edge needs to meet curvature requirement.
4. Forming: After the pre-bending step, in the first half of the JCO molding machine, after stamped steel, it is pressed into a 'J' shape while the on the other half of the same steel plate it is bent and pressed into a 'C' shape, then the final opening forms an 'O' shape.
5. Pre-welding: This is to make a welded pipe steel a straight seam after it has been formed and then use gas welding seam (MAG) for continuous welding.
6. Inside weld: This is done with a tandem multi-wire submerged arc welding (about four wire) on the inner part of the straight seam welded steel pipe.
7. Outside Weld: Outside weld is the tandem multi-wire submerged arc welding on the outer part of the LSAW steel pipe welding.
8. Ultrasonic Testing: Outside and inside of the straight seam welded steel pipe and both sides of the base material are welded with 100% inspection.
9. X-ray inspection: X-ray industrial TV inspection is carried out on the inside and outside using image processing system to make sure there is detection sensitivity.
10. Expansion: This is for accomplishing submerged arc welding and straight seam steel pipe length hole diameter so as to improve the steel tube's size precision and improve the distribution of stress in the steel tube.
11. Hydraulic test: This is carried out on the hydraulic test machine for steel after expanding by-root test for ensuring the steel pipe meets the standard requirements with the machine having an automatic recording and storage capabilities.
12. Chamfering: This involves the inspection carried out on the steel pipe at the end of the whole process.