Classification and assortment of steel welded pipes and profiles Welding

Steel Welded Pipes are classified into two categories: seamless and welded. Seamless steel pipes are made by hot-rolling or cold-drawing, while welded steel pipes are made by welding steel sheets or plates together. Welded steel pipes can be further divided into three types: electric resistance welded (ERW), high-frequency welded (HFW), and submerged arc welded (SAW) pipes.

Welded steel profiles, also known as structural steel shapes, are classified based on their shape and application. They can be divided into four main categories: angles, channels, tees, and zees. These profiles are used in construction, machinery, and equipment manufacturing, among other industries.

Welded steel pipes and profiles also come in different grades and sizes, depending on the application and industry they are used in. For example, pipes used in the oil and gas industry must meet specific requirements and standards such as API 5L, while pipes used in the construction industry may have different requirements.

Among them, a very important part is occupied by steel pipes , which in most cases cannot be replaced. As for the construction of gas pipelines and water pipelines , to this day they have no analogue that could replace them.

Steel pipes can be divided into:

• Seamless - thanks to cross-screw rolling , the required dimensions of this type of pipe are achieved. Their main purpose is for the oil and gas industry, as they are very suitable for transporting and extracting oil and gas.
• Welded - this type of pipe is mainly produced using pipe welding units, and the ends of the workpiece are welded with high- frequency currents.

Today, our main topic is steel welded pipes . Unlike seamless, they are much lighter, which makes them more widely used and distributed. Steel welded pipes are much stronger and resistant to both wear and high temperatures.

Classification and assortment of welded steel pipes

[caption id="attachment_212" align="aligncenter" width="300"] Welded steel pipe[/caption]

As for the types of steel welded pipes , they are mainly divided according to their shape, diameter size and the production technology used.

According to their shape, steel welded pipes are of two main types - round and profiled .

Round Welded pipes

The most common welded steel pipes are round . If we compare them with the square ones, for example, with the same circumference of both pipes, then the area of ​​the round ones is larger. This makes them ideal for transporting larger volumes of liquids .

On the other hand, round steel welded pipes have some limitations. With some kind of bending , the round tube does not have the rigidity and resistance that the square tube has. That is exactly why it is not suitable in certain cases.

Round steel welded pipes are divided according to their diameter, and they are:

• steel pipes with a small diameter - up to 114 mm .
• steel pipes with an average diameter - between 114 - 480 mm .
• wide diameter steel pipes: from 480 mm upwards .

The pipes, which have a large diameter , are made of thicker sheets, as they are mainly used for the construction of highway gas and oil pipelines , sewers and others.

While those of small and medium diameter are made from hot or cold-rolled coils. Their application is most widespread in the laying of water pipes and gas communications in the residential and communal sphere and industry.

Profile pipes

As for the profile steel welded pipes , they have the greatest plasticity, rigidity and strength in contrast to the round ones. Due to their large cross-section, as well as resistance to bending and twisting, they can reduce their own weight.

Therefore, this in turn makes them more widely used in various industries . They are most widely used in construction and the construction of pipelines.

From the point of view of the section, they are mainly divided into:

• With a square section
• With a rectangular section

Of course, along with them, there are steel welded pipes of other shapes, designed for specific needs. Among the main types of pipes , you will also find oval- shaped , drop-shaped cross-section and others.

Welded steel pipes are made by welding steel plates or steel coils after they have been first rolled.

The welded steel pipe is then cold drawn through a die and over a mandrel to create the finished shape. The pipes can vary in diameter from a few millimetres to several metres and can be used for a wide variety of applications, including carrying fluids such as gas, oil or water.

There are two main types of welded steel pipe: ERW (electric resistance welding) and EFW (electric fusion welding). ERW pipes are made by passing a hot steel plate through a set of rollers to form a tube, before being welded together using an electric current. EFW pipes are made by passing a hot steel plate through a set of rollers to form a tube, before being welded together using an electric current.

The advantage of EFW over ERW is that it does not require a separate step of adding a filler material, as the welding is done with an electric current. Welded steel pipes can be classified into four main categories: - Carbon steel pipes: These pipes are made from carbon steel and are used for carrying fluids such as water, oil or gas. - Stainless steel pipes: These pipes are made from stainless steel and are used for carrying fluids such as water, oil or gas. - Alloy steel pipes: These pipes are made from alloy steel and are used for carrying fluids such

Production technology of steel welded pipes

The production technology of steel welded pipes has developed rapidly in recent years.

[caption id="attachment_201" align="aligncenter" width="300"] Spot welding[/caption]

The annual output of welded pipes in China has increased from 3.3 million tons in 2001 to 10.8 million tons in 2010, and the welded pipe market share has increased from 15% to 36%. The development of the welding pipe industry has promoted the development of the entire metallurgical industry. The production technology of steel welded pipes mainly includes three aspects: material preparation, pipe welding and post-weld heat treatment.

(1) Material preparation: the choice of steel grades and chemical composition of welding materials must meet the requirements of the relevant national standards;

(2) Pipe welding: according to the requirements of the drawings, the material is cut into pipes of various diameters and lengths, and then sent to the welding unit for welding. The welding unit is generally composed of a welding power supply, a welding torch, a wire feeder and a water cooling system.

The welding process parameters are pre-set according to the type of welding wire and welding current, and the welding speed is automatically adjusted according to the welding current. The welding wire is continuously fed into the welding pool through the contact tip, and the welding torch moves along the weld to form a seam. In order to ensure the quality of the weld, the welder must have certain welding skills;

(3) After-weld heat treatment: the heat treatment after welding is generally carried

Steel welded pipes can be made using different technologies.

They are divided according to:

• the temperature of the formed metal - they can be made by cold forming or by hot sheet forming.
• the method of making the pipes with finite dimensions - they are made in calibration cells of forming-welding machines or on reducer rolling mills.
• process method - making small and medium size pipes by continuous process and making large diameter pipes by separate process.
• the amount and direction of welding seams - small-diameter single- seam pipes , medium-diameter double-seam pipes; spiral-seam tubes with a much wider diameter.
• the welding method - with high-frequency currents, using inert gases, with ultrasound, with direct current, electric arc welding, induction, plasma, electron beam and electric resistance welding.

Steel Welded Pipes Applications

Steel welded pipes find extremely wide application. That is why today we will present to you some of the main industries and industries in which they are most often used.

[caption id="attachment_203" align="aligncenter" width="300"] Spot welding in the car Industry[/caption]

Accordingly, they can be found in areas such as:

• construction and residential structures - especially for internal and external communications of buildings
• the furniture industry
• mechanical engineering
• industrial communications

In addition, it is worth mentioning that they are used for the construction of linear pipes , which serve to transfer oil and natural gas from oil and gas fields to certain storage facilities and reservoirs. Last but not least, they serve to build highway and industrial pipelines over long distances.

Advantages and disadvantages of steel welded pipes

Due to many of the requirements and regulations that exist in a number of countries, welded steel pipes are the only type of pipe that can be used for the construction of certain types of installations such as the transmission of gas, oil and the construction of long pipelines.

In addition, they have additional advantages that prove their widespread use:

• resistance at high temperatures.
• withstand very high pressure.
• longer service life.
• withstand mechanical damage and bending.

Of course, along with their advantages, there are also some major disadvantages:

• difficult to install as they require additional skills and devices to be able to install them.
• have more weight than plastic pipes.
• have electrical conductivity that poses a risk in the event of a malfunction.
• corrosion formation and a relatively high purchase price.

Conclusion

In conclusion, the classification and assortment of steel welded pipes and profiles are essential for proper selection and use in various industrial and construction applications. Welded steel pipes are classified into seamless and welded, and further divided into ERW, HFW, and SAW pipes.

Welded steel profiles, also known as structural steel shapes, are classified based on their shape and application.

They come in different grades and sizes depending on the industry they are used in, such as API 5L for oil and gas industry.

Understanding the classification and assortment of welded steel pipes and profiles can help ensure that the right type of pipe or profile is selected for a specific application and that it meets the necessary standards and requirements.