What are the differences between straight seam welded pipe and submerged arc welded pipe?

What are the differences between straight seam welded pipe and submerged arc welded pipe?

 Straight seam welded pipe and submerged arc welded pipe are two different welded steel pipe. Normally we separate the two pipes though wall thickness. If the wall thickness over 16MM, that will be submerged arc welded pipe; if the wall thickness less than 16MM, that will be straight seam welded pipe. They are the two most commonly used welded pipes in various industries including construction, oil and gas, and transportation. Although they are both welded pipes, there are some key differences between the two. LEFIN STEEL can produces the two types of steel pipes.

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Straight seam welded pipe:

Processing process:

 1. The steel coil is uncoiled and passed through a series of shearing and leveling machines to form a flat and straight steel strip. The strips are then fed into a welding machine and welded lengthwise to form a continuous seam.

 2. With the high-frequency resistance welding (HFW) process, electrodes and a power source are used to heat and melt the steel at the joint.

 3. The pipeline undergoes a series of testing and inspection processes including pressure testing, ultrasonic testing, visual inspection and magnetic particle inspection.

 4. Cut and coat the straight seam welded pipe to prevent corrosion.

Advantages:

1. Straight seam welded pipes are produced using high-speed welding technology and have high production efficiency.

2. The welding process of straight seam welded pipes is automated, which improves efficiency.

3. Straight seam welded pipe has a consistent thickness and is made of high-quality steel, making it resistant to corrosion and other forms of damage.

4. Straight seam welded pipes are widely used, such as oil and gas pipelines, water supply systems, sewage systems, etc. They are also used in the construction industry for building structures such as bridges and buildings.

5. Longitudinal welded pipes require minimal maintenance. They are resistant to corrosion and rust, making them ideal for harsh environments.

Application:

1. One of the main applications of straight seam welded pipes is the construction industry. These pipes are an important part of the construction of high-rise buildings, bridges, and other types of infrastructure.

2. Straight seam welded pipes are usually used to transport natural gas, oil, water and other fluids.

3. Another important application of straight seam welded pipes is in cargo transportation. They are used in the manufacture of trucks, railroads, ships and pipelines, among other things.

4. Straight seam welded pipes are also widely used in the manufacturing industry. They are used in the production of various types of machinery.

Submerged arc welded pipe:

Processing process:

 1. Prepare the edges of the pipe to be welded. The edges are cut and beveled to create V-shaped grooves to ensure proper fusion and penetration of the weld.

 2. Align and clamp the ends of the pipe in the welding machine, which moves the pipe through the welding head along the conveyor system.
 3. During the welding process, the welding head moves along the length of the pipe, depositing filler metal into the groove at a rate determined by the machine controls.

 4. Granular flux is deposited on the welding area as a protective cover. The flux melts and flows, forming slag that covers the weld. This slag protects the weld from atmospheric effects and improves its metallurgical properties.
 5. After welding is completed, gradually cool the welded pipe to avoid forming any potential defects in the weld. The slag is then removed mechanically or by sand blasting.
 6. Conduct various quality tests on welded pipes, including hydrostatic pressure testing and ultrasonic inspection, to ensure that they meet industry standards.

Advantages:

 1. Submerged arc welding creates an efficient weld, ensuring the highest quality and strength of the pipe.
 2. Submerged arc welding is a high-productivity welding technology with faster welding speeds, reducing the total time and cost required to produce welded pipes.
 3. The submerged arc welded pipe adopts an efficient welding process, and the strength of the welded joint is the same as or even stronger than the base material.

 4. Submerged arc welding can be used to weld a variety of materials, including carbon steel, stainless steel, low alloy steel, etc. Can be used in a variety of industries including oil and gas, construction and manufacturing.

 5. Submerged arc welding is an automated process with a low defect rate, which can ensure consistent welding quality and reduce the possibility of defects and errors in finished products.

 6. Submerged arc welding produces a narrow heat-affected zone, which helps minimize the risk of deformation and cracking of the welded pipe and helps improve the overall quality of the welded pipe.

 7. Submerged arc welded pipes are cost-effective compared to other welding methods. This process has lower labor requirements and can save production costs.

Application:

 1. One of the main uses of submerged arc welded pipes is oil and natural gas. The thick walls of the pipes ensure safe transport of materials over long distances.

 2. Submerged arc welded pipes have corrosion resistance and are often used in the chemical industry.

 3. Submerged arc welded pipes are used in the water supply industry and can transport drinking water and wastewater. Meets residential and industrial water supply needs.

 4. Submerged arc welded pipes are used for piling and structural purposes. Due to their high strength and durability, these pipes are ideal for supporting buildings and bridges.

 5. Submerged arc welded pipes are also used in tunnels and underground structures to provide a strong and stable foundation.

Differences :

 1. Straight seam welded pipes are made by continuously rolling strip steel and using high-frequency current to weld the edges together. Submerged arc welded pipe is formed by feeding bare metal filler wire into the welding area.

 2. Straight seam welding is faster, can produce pipes in a shorter time, and is more suitable for mass production. Submerged arc welding is a slower process, but it produces high-quality welds that are more uniform and durable.

 3. The production cost of straight seam welded pipes is lower, while submerged arc welded pipes require specialized equipment and highly skilled workers, and the cost is higher.

 4. Straight seam welded pipes can be produced in a variety of sizes from small to large diameters, while submerged arc welded pipes are usually used for large diameter pipes. 
Both straight seam welded pipes and submerged arc welded pipes have their own advantages and disadvantages. Different wall thicknesses also have different production processes. You can choose the production process according to the size you need, the application environment and other factors.