Submerged Arc Welding Advantages and Disadvantages

 

submerged arc welding technique

Submerged Arc Welding Technique

Submerged Arc Welding (SAW) is a specialized technique widely used in heavy industry sectors such as shipbuilding and structural steel fabrication. While SAW is recognized for enhancing welding productivity and quality, it also presents certain operational challenges.

This article provides a balanced overview, helping businesses understand when and how SAW can be effectively integrated into their projects. You will gain insight into both the potential benefits and the considerations needed to implement this technology effectively in their operations.

So, let’s get started!

Submerged Arc Welding

Submerged Arc Welding Components Involved

Submerged Arc Welding Components Involved

Submerged arc welding (SAW) is a highly efficient automated or semi-automated welding process predominantly used for joining metals. It employs a continuous, consumable electrode and a blanket of granular fusible flux, which becomes conductive when molten and provides a current path between the workpiece and the electrode.

The heat generated by the arc, formed under the flux, melts the electrode, flux, and the work materials, facilitating the formation of a weld.

Some of the applications of submerged arc welding are:

  • Shipbuilding
  • Offshore construction
  • Structural steel fabrication
  • Pipeline manufacturing
  • Pressure vessels and tank fabrication
  • Wind tower fabrication
  • Railroad construction
  • Heavy equipment manufacturing
  • Industrial boiler manufacturing
  • Military and defense equipment fabrication

Advantages of Submerged Arc Welding

Submerged arc welding offers significant productivity benefits and superior weld quality, particularly in industrial settings demanding robust, long-lasting joints. Its automated nature ensures consistent results, reducing the likelihood of human error while speeding up the welding process.

The use of a flux blanket not only suppresses harmful fumes and UV radiation, promoting a safer working environment but also enhances the overall quality of the weld by preventing contamination and oxidation.

This method is particularly effective for thick materials, achieving deep penetration with minimal thermal distortion, which is crucial for maintaining the integrity and strength of the weld.

High Quality Welds

Metal worker using a grinder

SAW produces high quality welds

Submerged arc welding plays a crucial role in achieving high-quality welds due to its unique process and characteristics.

It ensures superior weld quality through its use of a granular flux that covers and protects the weld pool, effectively shielding it from atmospheric contamination and oxidation.

This protective flux not only prevents impurities but also refines the weld by modifying its chemical composition, which can enhance the mechanical properties such as strength and toughness.

The process promotes a smooth and steady transfer of filler metal from the electrode to the weld pool, leading to uniform weld beads and minimizing defects like porosity and inclusions.

The consistency of the heat source and the controlled environment results in deep weld penetration and superior thermal efficiency, ensuring strong, durable welds with less need for post-weld machining or finishing.

High Efficiency

Submerged arc welding (SAW) achieves high efficiency through its high deposition rate, enabling more weld material to be applied in less time compared to traditional welding methods.

The continuous feed of the electrode wire allows for long, uninterrupted welds, significantly reducing the need for stops to replace electrodes, which is often necessary in manual welding processes.

This continuous operation is crucial in large-scale industrial projects like structural steel construction or pipeline manufacturing, where reducing project time and labor costs is essential.

The automated nature of SAW minimizes manual labor, allowing for precise control over welding parameters and consistent welding conditions, thereby ensuring high throughput without compromising weld quality.

The efficiency of SAW not only accelerates the welding process but also enhances overall project efficiency, making it highly suitable for projects requiring both extensive welding and superior quality outcomes.

Effective for Thick Materials

SAW is effective for thick materials

SAW is effective for thick materials

Submerged arc welding is especially effective for joining thick materials due to its capability for deep penetration. This attribute is crucial in industries such as shipbuilding and heavy machinery manufacturing, where thick steel plates or components are common.

Single Pass Welding

The deep penetration achieved by SAW often allows for the welding of thick sections in a single pass. This is a significant advantage over other welding techniques that may require multiple passes to achieve a weld of similar depth, leading to increased labor and time.

Reduced Welding Time

By enabling the welding of thick materials in fewer passes, SAW significantly reduces the total welding time required for a project. This efficiency is not only beneficial in terms of speeding up production but also helps in lowering energy consumption and labor costs.

Consistent Quality in Thick Welds

The ability of SAW to penetrate deeply into the workpiece results in strong, durable welds with consistent quality. This is particularly important for structural applications where the integrity of the weld can impact the overall safety and durability of the structure.

Minimal Welding Fume Exposure

Submerged arc welding significantly reduces the exposure to welding fumes and ultraviolet radiation, thanks to its distinctive process where the welding arc operates beneath a blanket of granular flux.

This flux not only acts as a barrier between the arc and the environment, effectively trapping the fumes that are generated during the welding process, but it also blocks the intense ultraviolet radiation that is typically emitted.

The reduction in airborne contaminants and harmful radiation creates a much safer working environment, particularly important in enclosed or indoor settings where ventilation may be limited.

Moreover, the decreased level of fumes contributes to better overall health conditions for welding personnel, reducing the risk of respiratory problems and other health issues associated with long-term exposure to welding emissions. This aspect of SAW is a significant benefit, enhancing worker safety and compliance with occupational health and safety regulations.

Low Hydrogen Welds

Low Hydrogen Electrodes

Low Hydrogen Electrodes

It utilizes a flux that plays a crucial role in minimizing the hydrogen content in welds. This is particularly important because hydrogen, when present in the weld metal, can lead to hydrogen-induced cracking, a common and detrimental defect that compromises the integrity of the weld.

The flux used in SAW acts as a barrier that prevents atmospheric gases, including hydrogen, from contaminating the weld pool. Additionally, the chemical composition of the flux is designed to absorb hydrogen that may be released during the welding process.

By reducing the hydrogen levels, the flux helps produce welds that are less susceptible to cracking and have higher structural integrity. This characteristic is especially beneficial in high-strength steels and other sensitive materials where the purity of the weld is crucial for maintaining the material’s strength and performance under stress.

Reduced Welding Distortion

This welding effectively minimizes material distortion, a common challenge in many welding processes due to uneven heating and cooling. In SAW, the high heat input ensures that the heat is thoroughly and evenly distributed through the material.

This uniform heat distribution is crucial as it lessens the thermal gradients that typically cause the material to warp or distort during cooling. Moreover, SAW allows for a controlled cooling rate facilitated by the insulating properties of the flux that covers the weld area.

This flux not only protects the weld seam from external contaminants but also slows down the rate of cooling, preventing the formation of stresses that can lead to warping. As a result, the finished welds are not only cleaner and smoother but also maintain better dimensional stability, enhancing the overall quality and strength of the structure being welded.

Automated Operation

SAW is commonly performed using automated or semi-automated systems, which significantly enhances the precision and control of the welding process. This level of automation ensures that the welding parameters, such as speed, heat input, and wire feed rate, are consistently maintained, resulting in uniform weld quality across projects.

Automation also allows for continuous operation without the frequent stops and starts associated with manual welding, further improving weld integrity and appearance. Additionally, the use of automated systems in SAW reduces the reliance on highly skilled labor, which can be a significant cost factor in welding operations.

By minimizing human intervention, these systems not only lower the potential for errors but also contribute to overall cost savings in labor. This automated approach is particularly advantageous in large-scale and repetitive welding tasks where consistency and efficiency are critical.

Good Mechanical Properties

Welds produced through submerged arc welding are known for their excellent mechanical properties, such as enhanced toughness and strength. This superior performance is primarily due to the deep penetration and uniform heat distribution that SAW provides, which facilitates a strong metallurgical bond between the welded materials.

The comprehensive fusion of the base and filler metals results in a weld that closely matches or exceeds the strength of the base materials themselves. Additionally, the protective flux layer used in SAW plays a crucial role in achieving these properties.

It shields the weld pool from contaminants and atmospheric interference during the welding process, which could otherwise compromise the integrity of the weld.

This results in a cleaner and more consistent grain structure within the weld zone, significantly improving its mechanical properties. The robustness of SAW welds makes them ideal for critical applications in demanding environments where mechanical strength and durability are paramount.

Less Operator Skill Required

Less Operator Skills Required

Less Operator Skills Required

Due to its mechanized nature, submerged arc welding (SAW) demands considerably less operator skill compared to manual welding processes such as TIG or stick welding.

This is primarily because the core of the SAW process—controlling the arc, feeding the wire, and applying the flux—is automated, which standardizes many of the tasks that would require precise manual control in other welding techniques.

This automation ensures that even operators with less experience can achieve high-quality welds, as the machine regulates critical variables like speed, arc length, and temperature.

Consequently, the training period for SAW operators is shorter, focusing more on overseeing the process and maintaining equipment rather than mastering the intricate hand skills required for manual welding.

This reduction in required skill level not only makes it easier to scale up welding operations but also helps in reducing labor costs, as workers do not need to be highly specialized to operate SAW equipment effectively.

Excellent for Outdoor Use

Submerged Arc Welding in outdoors

Submerged Arc Welding in Outdoors

Submerged arc welding is particularly advantageous for outdoor welding projects because it is less sensitive to external environmental conditions, such as wind. This resilience is largely due to the thick layer of flux that covers the weld pool during the welding process.

The flux serves as a shield, protecting the molten metal from being exposed to the air and disturbances such as wind, which can adversely affect other welding processes by dispersing shielding gases and introducing contaminants into the weld.

This characteristic allows SAW to maintain a stable arc and consistent weld quality even in less controlled outdoor environments. As a result, SAW is a reliable choice for construction and repair tasks in open settings where other welding methods might struggle with variability caused by natural elements.

Scalable and Versatile

This method stands out for its scalability and versatility, making it well-suited to a broad range of industrial applications. The process can be easily adjusted to accommodate different job sizes and requirements, from small-scale operations to large, extensive projects.

This scalability is primarily facilitated by the ability to adjust key parameters such as the welding speed, heat input, and the size of the electrode. Additionally, SAW’s versatility is evident in its wide application across various industries.

It is extensively used in shipbuilding, where strong, durable welds are crucial for the integrity of ship structures, and in bridge construction, which demands consistent high-quality welds for safety.

The process is also ideal for the manufacturing of large tanks and vessels, where the ability to produce long, continuous welds improves efficiency and structural integrity. This adaptability ensures that SAW remains a valuable welding technique for diverse and demanding welding tasks.

Cost-Effective for Large Projects

Lincmatic video

SAW used for a large-scale project

It is particularly cost-effective for large-scale welding operations, an advantage that stems from its high deposition rates and rapid welding speeds. In projects where extensive amounts of welding are required, such as in the construction of ships or large infrastructure projects, the efficiency of SAW translates into significant time and cost savings.

The process enables a larger volume of weld material to be deposited in less time compared to other welding methods. This efficiency reduces the overall duration of the project, which in turn lowers labor costs and expedites project completion.

Additionally, the automated nature of SAW minimizes the need for skilled labor, further reducing costs. The combination of these factors makes SAW an economically advantageous choice for projects where the scale of welding work would otherwise demand considerable resources and time.

Clean Process

The process is recognized for its clean operating process, largely due to the role of the flux used during welding. This flux covers the entire welding area, effectively preventing spatter, which is common in many other welding methods.

Spatter refers to the droplets of molten material that can be ejected from the welding zone, which not only creates a mess but also can compromise the quality of the weld by adhering to the surface of the workpiece.

Additionally, the flux acts to suppress the welding arc itself, reducing the bright light and heavy smoke produced in other welding processes. This suppression helps maintain a clear and clean working environment, enhancing safety and reducing the need for extensive post-weld cleaning.

The cleanliness of SAW makes it particularly useful in applications where maintaining the integrity and appearance of the weld and the surrounding areas is crucial.

Minimal Post-Weld Cleanup

The simplicity of post-weld cleanup in submerged arc welding is another notable benefit, primarily due to the characteristics of the slag that forms during the welding process. This slag, which originates from the flux that covers the weld pool, solidifies on cooling and adheres less firmly to the surface than in many other welding methods.

As a result, it can be easily chipped away and removed, often in large, contiguous pieces. This easy removal of slag significantly reduces the time and effort required for post-weld cleaning, streamlining the overall workflow and increasing productivity.

The reduced cleanup effort shortens project timelines and minimizes the labor involved in finishing, making the welding process more efficient. This aspect is particularly valuable in large-scale welding operations, where extensive cleanup can otherwise add significant time and cost to the project.

Disadvantages of Submerged Arc Welding

Besides the advantages, there are multiple disadvantages of submerged arc welding. Some of them are briefly discussed below:

Limited Positions

Submerged Arc Welding is mostly used for flat or horizontal welds because the flux used in the process can spill when used in vertical or overhead positions, limiting its applicability. This makes it unsuitable for a variety of projects that require flexible welding orientations.

Less Versatility

This method is great for long, straight seams but isn’t as effective for short welds or complex shapes that require more precise welding techniques. As a result, its use is restricted to specific types of projects, reducing its overall adaptability.

High Initial Investment

Setting up a Submerged Arc Welding operation can be expensive. The equipment and materials, like automated feed systems and flux recovery units, require a significant upfront cost. This high cost can be a barrier for smaller operations or those just starting out.

Restriction to Ferrous Metals: SAW is primarily used for welding steel and some nickel alloys, but it isn’t suitable for materials like aluminum or copper, which limits its use in diverse industries. This restricts its applications primarily to projects involving ferrous materials.

Limited Accessibility

The equipment setup for SAW, especially in automated configurations, can be bulky and complex, making it difficult to use in confined spaces or less accessible job sites. This can limit its effectiveness in smaller or more complex environments where space is at a premium.

Cleanup and Waste Management

While the process is relatively clean, managing the leftover flux and slag can be cumbersome. They need to be properly disposed of or recycled, adding to the operational overhead. This environmental and logistical consideration can complicate project management.

Flux Handling and Maintenance

Maintaining the quality of flux is crucial for high-quality welds. Storing and handling flux to avoid contamination and moisture can be challenging. Poor flux quality can directly affect the strength and integrity of the weld.

Requires Careful Setup

Achieving consistent, high-quality results with SAW requires precise control over various parameters like voltage, current, and travel speed, which means setup and monitoring need to be done carefully. Any error in setup can lead to poor weld quality, which may not be evident until failure occurs.

Thermal Distortion

Although SAW typically produces less distortion compared to other methods, the high heat input can still lead to warping, especially when welding thinner materials. This can necessitate additional measures to mitigate distortion, adding time and cost to projects.

Operator Safety

Even though there’s reduced exposure to fumes and UV light, the operators must handle heavy equipment and manage high temperatures, which pose safety risks. Proper training and safety equipment are essential to minimize risks.

Limited Operator Feedback

Because the weld pool is covered by flux, operators can’t see the weld as it forms, which makes it harder to adjust the process in real-time or catch defects as they occur. This lack of visibility can delay the detection of issues, potentially impacting the overall project timeline and quality.

Conclusion

Submerged arc welding (SAW) stands out for its ability to deliver high-quality, efficient welds, especially suitable for large-scale industrial applications that involve thick materials and long, continuous seams. Its high deposition rates, deep penetration, and automated nature ensure that projects are completed quickly and with consistent weld quality, leading to significant time and cost savings.

However, the technique does have its limitations, such as its suitability primarily for flat or horizontal positions, higher initial costs, and restricted material compatibility. These factors should be carefully considered when selecting a welding method for your project.

For businesses weighing the benefits and drawbacks of submerged arc welding or for those seeking expert guidance on implementing this technology in their operations, SENLISWELD offers comprehensive welding solutions tailored to your specific needs.

Contact SENLISWELD today for all your welding needs and ensure your projects benefit from the highest standards of efficiency and quality.

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