What is Submerged Arc Welding Used For: Applications & Benefits

Submerged arc welding is a widely used welding process in various industries. It is a type of arc welding process that involves the formation of an arc between a continuously fed electrode and the workpiece. The arc is submerged under a layer of granular flux, which protects the weld from atmospheric contamination and provides a shielding effect.

Submerged arc welding is known for its high deposition rates and deep penetration capabilities, making it a popular choice for welding thick materials. It is commonly used in the fabrication of large structures, such as pressure vessels, pipelines, and offshore platforms. Additionally, it is often used in the welding of longitudinally welded pipes, as it can produce high-quality, consistent welds over long distances.

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Submerged arc welding is a versatile process that can be used for a variety of applications. Its ability to produce high-quality welds quickly and efficiently makes it a popular choice in many industries. In the following sections, I will discuss the various applications of submerged arc welding and its advantages and disadvantages.

Fundamentals of Submerged Arc Welding

Submerged arc welding (SAW) is a welding process that uses a continuously fed wire electrode and a granular mineral flux to create a weld. The process involves submerging the arc and molten weld pool beneath a layer of flux, which protects the weld from atmospheric contamination.

The SAW process can be used to weld a variety of metals, including carbon steels, stainless steels, and nickel alloys. The process is particularly well-suited for welding thick sections of material, as it is capable of producing high-quality welds with deep penetration.

The basic components of a submerged arc welding system include a power source, a wire feeder, a welding head, and a flux hopper. The power source provides the electrical energy needed to create the welding arc, while the wire feeder delivers the wire electrode to the weld. The welding head holds the wire electrode and positions it relative to the workpiece, while the flux hopper dispenses the flux onto the weld.

During the welding process, the wire electrode is fed continuously into the weld pool, while the flux covers the weld and protects it from atmospheric contamination. The heat generated by the welding arc melts the wire electrode and the base metal, creating a molten weld pool. As the weld cools, the flux solidifies and forms a slag layer on top of the weld, which can be easily removed after the welding is complete.

The SAW process is a reliable and efficient method for welding a wide range of materials. Its ability to produce high-quality welds with deep penetration makes it particularly well-suited for welding thick sections of material, while its ability to protect the weld from atmospheric contamination ensures that the resulting weld is of high quality.

Applications of Submerged Arc Welding

As a welding process, submerged arc welding is widely used in many industries due to its efficiency, high quality, and ability to create deep and neat welds. In this section, I will discuss some of the most common applications of submerged arc welding.

Pipeline Construction

Submerged arc welding is commonly used in pipeline construction for its ability to create high-quality welds at high speeds. The process is particularly effective for welding large-diameter pipes. In pipeline construction, submerged arc welding is often used to join pipe sections together and to weld on fittings and flanges.

Structural Steel Fabrication

Submerged arc welding is also widely used in structural steel fabrication. The process is particularly effective for welding thick plates and for creating clean, uniform welds on large structures. In structural steel fabrication, submerged arc welding is often used for welding beams, columns, trusses, and other components.

Shipbuilding and Repair

Submerged arc welding is commonly used in shipbuilding and repair due to its ability to create high-quality welds on thick plates. The process is particularly effective for welding the hulls of large ships and for creating clean, uniform welds on complex structures. In shipbuilding and repair, submerged arc welding is often used for welding decks, bulkheads, and other components.

Wind Tower Production

Submerged arc welding is also widely used in wind tower production. The process is particularly effective for welding the large, thick plates used to construct wind tower sections. In wind tower production, submerged arc welding is often used for welding tower sections together and for welding on flanges and other components.

In conclusion, submerged arc welding is a versatile and efficient welding process that is widely used in many industries. Its ability to create high-quality welds at high speeds makes it an ideal choice for welding large structures, such as pipelines, ships, and wind towers.

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Advantages of Submerged Arc Welding

As a welding process, submerged arc welding (SAW) offers several advantages that make it a popular choice in various sectors of the metalworking industry. In this section, I will discuss some of the key advantages of SAW.

High Deposition Rates

One of the most significant advantages of submerged arc welding is its high deposition rate. This process can deposit large amounts of metal in a short period, making it ideal for welding thick plates and large structures. With SAW, it is possible to achieve deposition rates of up to 45 kg/h, which is much higher than other welding processes.

Deep Weld Penetration

Submerged arc welding also offers deep weld penetration, which means that the weld metal can penetrate deep into the base metal. This results in a strong and reliable weld joint that can withstand high stress and strain. The deep weld penetration also makes SAW suitable for welding thick plates and structures.

Minimal Welding Fume Emission

Another advantage of submerged arc welding is that it produces minimal welding fume emission. This is because the welding arc is completely covered by a layer of flux, which prevents the formation of welding fumes. As a result, SAW is a safer welding process for the welder and the environment.

Good Mechanical Properties

Finally, submerged arc welding produces welds with good mechanical properties. The weld metal has a high tensile strength, which means that it can withstand high stress and strain. The welds also have good impact toughness, which makes them resistant to cracking and other types of damage.

Submerged arc welding is a welding process that offers several advantages, including high deposition rates, deep weld penetration, minimal welding fume emission, and good mechanical properties. These advantages make SAW a popular choice for welding thick plates and large structures in various sectors of the metalworking industry.

Equipment and Materials

Welding Power Sources

For submerged arc welding, a power source is used to provide the electric current that melts the electrode and the base metal. The power source must be able to provide a constant voltage and amperage to ensure a stable arc and consistent weld quality. Typically, direct current (DC) power sources are used for submerged arc welding.

Flux and Wire Combinations

The flux used in submerged arc welding serves multiple purposes, including shielding the arc from the atmosphere, providing a protective layer over the weld, and controlling the weld’s chemical composition. The wire used in submerged arc welding is typically a solid or tubular electrode that is continuously fed into the weld pool.

The selection of flux and wire combinations depends on the application and the desired properties of the weld. Different combinations can be used to achieve specific results, such as increased strength or corrosion resistance.

Welding Heads and Tractors

Submerged arc welding can be performed manually or with automated equipment. Welding heads and tractors are used to automate the process, allowing for greater precision and efficiency. Welding heads can be fixed or adjustable and are designed to hold the electrode and control its movement. Welding tractors are used to move the welding head along the weld path, ensuring consistent travel speed and weld quality.

The equipment and materials used in submerged arc welding play a critical role in achieving high-quality welds. Proper selection and maintenance of these components are essential for successful welding operations.

Process Variables and Control

Current and Voltage

The submerged arc welding process requires precise control of both current and voltage to ensure a high-quality weld. The current is typically set between 300 and 1500 amps, depending on the thickness of the material being welded. The voltage is also an important factor, as it affects the penetration depth and the shape of the weld bead. A higher voltage will result in a wider and flatter weld bead, while a lower voltage will produce a narrower and more rounded bead.

Travel Speed

The travel speed of the welding torch is another important variable that affects the quality of the weld. If the travel speed is too slow, the weld bead will be too wide and shallow, resulting in poor penetration and a weak joint. If the travel speed is too fast, the weld bead will be too narrow and deep, which can cause excessive heat buildup and distortion of the workpiece. The ideal travel speed will depend on the thickness of the material, the current and voltage settings, and the type of flux being used.

Electrode Stick-out

The electrode stick-out, or the distance between the tip of the electrode and the workpiece, is also a critical variable in the submerged arc welding process. If the stick-out is too short, the electrode will be too close to the workpiece, which can cause the flux to boil and spatter, resulting in a poor-quality weld.

If the stick-out is too long, the arc will become unstable, which can cause the electrode to burn back into the flux, resulting in a loss of control and a poor-quality weld. The ideal stick-out will depend on the type and diameter of the electrode, as well as the current and voltage settings.

In summary, precise control of current, voltage, travel speed, and electrode stick-out is essential for producing high-quality welds in the submerged arc welding process. By carefully adjusting these variables, I can ensure that the weld bead is the right size and shape, and that the penetration depth is sufficient for the application.

Safety Considerations in Submerged Arc Welding

As a professional welder, safety should always be a top priority when working with any welding process, including submerged arc welding. Here are some important safety considerations to keep in mind:

Protective Equipment

When working with submerged arc welding, it is important to wear the proper protective equipment to prevent injuries. This includes:

• Welding helmet with a shaded lens to protect your eyes from the bright light
• Welding gloves to protect your hands from heat and sparks
• Fire-resistant clothing to protect your body from burns
• Respirator to protect your lungs from fumes and gases

Ventilation

Submerged arc welding produces fumes and gases that can be harmful if inhaled. It is important to work in a well-ventilated area or to use an exhaust system to remove the fumes and gases from the work area.

Electrical Safety

Submerged arc welding involves working with high voltage electricity. It is important to make sure that all electrical connections are secure and that the welding machine is grounded properly to prevent electrical shock.

Fire Safety

Submerged arc welding produces sparks and heat that can ignite flammable materials. It is important to keep a fire extinguisher nearby and to make sure that the work area is free of any flammable materials.

Training

Proper training is essential for safe and effective submerged arc welding. Make sure that you are trained in the proper use of the equipment and that you follow all safety guidelines and procedures.

By following these safety considerations, you can ensure that you are working safely and effectively with submerged arc welding.

Limitations and Challenges

Positional Restrictions

Submerged arc welding is not suitable for all positions. Welding in the vertical-up position is particularly challenging because the molten metal tends to sag and fall away from the joint. Welding in the overhead position is also difficult because the molten metal can fall onto the welder or the surrounding area. Welding in the flat and horizontal positions is much easier and more efficient.

Flux Handling and Recovery

One of the biggest challenges of submerged arc welding is handling and recovering the flux. The flux is a critical component of the welding process, as it provides protection from atmospheric contamination and helps to shape the weld.

The flux can be messy and difficult to handle, and it must be carefully stored and maintained to ensure consistent welding performance. In addition, the flux can be expensive, and recovering and reusing it can be time-consuming and labor-intensive.

Initial Equipment Investment

Submerged arc welding requires specialized equipment, including a power source, a wire feeder, a welding head, and a flux recovery system. This equipment can be expensive to purchase and maintain, and it requires a significant amount of space to set up and operate. In addition, the welding process can be slow and labor-intensive, which can increase the overall cost of the welding project.

Final Thoughts

Submerged arc welding is a powerful and versatile welding process that is widely used in heavy industry sectors such as shipbuilding and structural steel fabrication. It is not without its limitations and challenges, and it requires careful planning and preparation to ensure successful welding performance.