Submerged Arc Welding, or SAW, is a specialized process very commonly utilized within the heavy industries of shipbuilding and structural steel fabrication. Although submerged arc welding is known to increase both the productivity and quality of welding, a number of operational challenges are associated with it.

The following article provides an overall balanced view that shall help the businessman understand when and how SAW may be effectively integrated into their projects. You get a glimpse of both the possible advantages and considerations necessary to implement this technology effectively into their operations.

So, let us get going!

Submerged Arc Welding

Submerged Arc Welding Components Involved

Submerged arc welding is a very productive automated and semiautomated welding process employed principally for joining metals. It involves a continuous consumable electrode and a blanket of fusible granular flux, which when molten becomes conductive to provide a current path between the workpiece and electrode.
The arc generated beneath the flux develops sufficient heat which is able to melt the electrode, flux, and the work materials, thus assisting in creating a weld.
Some of the applications involving submerged arc welding are as follows:
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 has very big advantages in the productivity and quality of the weld in the industrial environment in terms of the required joints, strong and durable. It is automated in operation for great consistency and minimizes a possible human factor error, hence increasing the speed of welding.

A flux blanket suppresses noxious fumes and UV radiation, creating a much safer working environment; at the same time, it protects the weld pool against contamination and oxidation, hence helping to improve the quality of the weld.

A process which is explained to be very effective in thick materials reaches deep levels with a minimum heat distortion-very important for integrity and the strength of the weld.

High Quality Welds

SAW Produces High-quality Welds

Submerged arc welding is particularly important for reaching quality welds due to both the unique process and characteristics involved.

It gives quality welds due to the fact that it makes use of granular flux covering, protecting the pool from atmospheric contamination and oxidation.

It also prevents impurities and refines the weld by its action in modifying its chemical composition, which might enhance its mechanical properties such as strength and toughness. This allows smooth and steady transfer of filler metal from the electrode into the weld pool, yielding uniform weld beads and minimizing weld defects associated with porosity and inclusions.

The continuity of the heat source in the controlled environment provides deep weld penetration and good thermal efficiency that results in strong, durable welds with minimal post-weld machining or finishing.

High Efficiency

Submerged arc welding, or SAW, is an extremely high deposition-rate process; this enables more weld material to be deposited in less time than with conventional welding techniques.

This would imply that the continuous feed of the electrode wire can allow for longer welds without interruptions, while manual welding processes are normally stopped to change over electrodes.

This is quite significant in major projects such as structural steel construction or pipeline making, where saving time consequently the labor costs are of essence.

Because SAW is an automated process, human interference becomes less, and hence, it provides complete control over the welding parameters and maintains consistent welding conditions for yielding high output without compromising weld quality.

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

Submerged arc welding is particularly effective in thick materials joining due to its property of deep penetration. This property is very important in industries like shipbuilding and the manufacture of heavy machinery, where thick steel plates or other components are involved.

Single Pass Welding

The deep penetration achieved by SAW often enables the welding of thick sections in a single pass. This is a great advantage over those techniques of welding that may need several passes before getting a weld as deep, thus increased labour and time.

Reduced Welding Time

This is due to the fact that SAW can allow welding of thick materials in fewer passes, thus reducing drastically the total number required for any project. This efficiency offers advantage not only in speeding up production but is also useful in lowering energy consumption as well as labor costs.

Consistent Quality in Thick Welds

As a result of this deep penetration of SAW into the workpiece, a strong and durable weld with constant quality is yielded. This is very important in structural purposes where integrity at the point of welding might influence the overall safety and durability of the structure.

Minimum Exposure to Welding Fumes

Submerged arc welding is the process that significantly reduces exposure to welding fumes and ultraviolet radiation by virtue of its welding arc operation under a blanket of granular flux.

This flux not only acts as an interference between the arc and atmosphere for serving effectively in trapping the fumes generated during the welding process but also blocks the strong ultraviolet radiation usually emitted.

The reduction in the level of airborne contaminants and injurious radiation creates a much safer working environment, which is extremely important in an enclosed or indoor setting where ventilation might be at a minimal level.

The reduced quantity of fumes also creates a better health environment for the welding staff, since such vapor exposure is among the known causes of respiratory problems and other health conditions when it comes to long-term exposure to welding fumes.

This feature of SAW provides some cardinal benefits in improving the safety of workers and meeting the occupational health and safety requirements.

Low Hydrogen Welds

Low Hydrogen Electrodes

It employs a flux that keeps the hydrogen content in the welds as low as possible. This is important because hydrogen, when it appears in the metal of the weld, can give rise to hydrogenous cracking, one of the most common and serious defects that considerably reduce the quality of the weld.

In SAW, the flux used acts like a shield and prevents the atmospheric gases, Hydrogen among them, from contaminating the weld pool. Other than this, the chemical composition of the flux is such that it is able to soak up hydrogen if it is released during the welding process.

With flux reducing the hydrogen levels, welds produced are less likely to crack and hence have better structural integrity.

This attribute is particularly important, especially in high-strength steels and other sensitive materials in which the purity of the weld is highly crucial for retaining the strength and performance of the material under stress.

Reduced Welding Distortion

The welding, as a result of this process, effectively reduces the distortion on the material, which is mostly caused by other means of welding as the heat gained and dissipated poses a problem. In SAW, the high heat input requires the heat to be put throughout the material in a proper and uniform manner.

This is important, since a uniform heat distribution reduces the thermal gradients that normally cause warping or distortion during cooling of the material. SAW provides for a controlled cooling rate, occasioned by the insulating properties of the flux that covers the weld area.

This flux not only prevents the weld seam from external contaminants, but it also slows down the cooling process in order to prevent the growth of stresses that lead to warping.

The result is welds that are not only much cleaner and smoother but also have better dimensional stability. Their ultimate effect on the structure being welded is enhanced overall quality and strength.

Automation in Operation

In most cases, SAW is done automatically or semi-automatically, which exponentially affects the precision and control of the process. This will make sure that the parameters for welding, such as speed, heat input, and wire feed rate, remain the same throughout the process. The result is that weld quality would remain similar in all projects.

Automation of the process also means that the operation can run continuously without the frequent stops and starts occurring in manual welding, further improving weld integrity and appearance. Another advantage of using automated systems in SAW is that this process reduces reliance on highly skilled labor, one of the biggest cost factors in most welding operations.

These systems lower the degree of human interference, hence reducing the possibility of errors, and in addition to that, save costs in terms of labor expenses. In dealing with large batches of continuous welding operations, this process is helpful where consistency and efficiency are required.

Good Mechanical Properties

The mechanical properties of toughness and strength in submerged arc welding are very good. This is mainly attributed to the deep weld penetration and uniform heating that SAW provides, enabling a good metallurgical bond between the materials to be welded.

However, the important contribution of the protective flux layer used in SAW is that it ensures the complete melting of base and filler metals such that a weld with strength matching or even surpassing that of the base materials themselves is obtained.

It protects the weld pool from impurities and interference in the atmosphere during welding that may otherwise make the weld defective.

This cleans up the grain structure in the weld zone and makes it much more uniform, hence greatly improving the mechanical properties of the weld zone. In fact, the strength of SAW welds makes them highly suitable for applications that are critical and for which the operating environments are very harsh and call for exceptionally high mechanical strength and durability.

Less Operator Skill Required

Submerged arc welding does require much less operator skill than is required for the manual processes of TIG or stick welding due to its mechanized nature.

This is primarily a function of the fact that the core elements of the SAW process of arc control, wire feeding and flux application are automated. That basically uniformizes much of what other welding techniques require in the way of painstaking manual control.

The process warrants that less-experienced operators would produce welds of high quality, as the machine maintains the variables of speed, arc length, and temperature.

The training period for SAW operators is much shorter. This is because the training concerns mainly learning to monitor processes and maintain equipment rather than to master the complicated hand skills associated with the techniques of manual welding.

This lesser requirement for highly qualified operators makes scaling up easier in welding works, whereas the associated labor cost is also lower as, apparently, workers do not need to be so highly specialized in order to operate SAW equipment efficiently.

Suitable for Outdoor Applications

Submerged Arc Welding in Outdoors

With submerged arc welding, the major additional advantage is that it is suitable for welding outdoors, as it is less susceptible to ambient environmental conditions outside, such as wind. The main reason for such resilience is the fact that during welding, there is a thick layer of flux that keeps the weld pool covered.

The flux protects the molten metal from exposure to air and interference factors like wind-a problem common in many welding techniques which may disperse shielding gases and introduce contaminants into the weld.

Because of this nature, SAW can maintain a consistent arc and weld quality in less-controlled outdoors. For this reason, SAW is reliable for construction and repair work in the open where other methods are likely to show variations because of natural elements.

Scalable and Versatile

It has scalability and versatility, making this process quite apt for a wide range of industries. It can easily adapt to various job sizes, from small-scale operations to large, extensive projects.

This is largely made possible by the fact that many of the key variables, such as welding speed, heat input, and electrode size, can be changed. Besides, versatility can also be demonstrated in the varied range of applications for SAW.

Some of the broad uses are in shipbuilding, where tough and solid welds are necessitated by the very integrity of ship structures, and in bridge construction, which requires consistent and always quality welds as a matter of safety.

This method is also eminently suitable for the fabrication of the largest tanks and vessels, where long, continuous welds provide maximum efficiency along with high structural integrity. This versatility makes SAW one of the most valuable welding processes when it comes to very diverse and very demanding welding jobs.

Cost-Effective for Large Projects

SAW is used for a Large-scale project

It is especially economic in long-running welding jobs, a fact coming from its high deposition rates and fast welding speeds. Projects involving lots of welding, like the construction of ships or major infrastructure projects, will see huge savings in time and money with the efficiency of SAW.

The process allows for more weld material to be deposited in less time compared to other welding processes. This in turn saves the overall duration of the project, therefore reducing costs by minimizing labor and expediting the project.

Besides, SAW is an automatic process that requires a minimum of skilled labor; hence, it is less costly. These factors combine to make SAW economically viable in projects where the extent of welding work would have called for considerable resources and time.

Clean Process

It is also known as a clean process because of the way the operation occurs, mainly based on the role of the flux used during welding. The flux covers the entire area of welding, actually preventing spatter, which is common in many other welding methods.

Spatter consists of small droplets of molten material that might be thrown out from the welding zone. In addition to the mess it causes, spatter can compromise weld quality as it may stick to the surface of the workpiece.

Another contribution of flux is that it dampens the welding arc itself, reducing the brilliant light and the intense smoke developed in most other welding processes.

This dampening helps in keeping the working environment clear and clean and increases safety while reducing extensive post-weld cleaning. This cleanliness in SAW is advantageous when it comes to applications that demand that the integrity and appearance of the weld and surrounding areas remain intact.

Least Post-Weld Cleaning

Another very important advantage of submerged arc welding over other welding processes is in the post-weld cleanup, which again simply results from the nature of the slag that develops during the weld.

This develops as a result of flux covering the weld pool and solidifies as it cools. Slag in this process adheres less strongly to the surface compared to many other welding processes.

It can, then, be easily chipped off and removed in large, contiguous pieces. This easily removes slag and greatly reduces the time and effort required for post-weld cleaning, streamlining the workflow and allowing more jobs to be completed in less time.

The reduced cleaning effort now shortens the overall duration of the project and reduces manpower to complete the welds, further streamlining the welding process. This is particularly useful in major welding operations where extended cleanup can certainly add a good deal of time and expense to the project.

Disadvantages of Submerged Arc Welding

Apart from the several advantages, there are also numerous submerged arc welding disadvantages. Some of them are briefly described below:

Restrain Positions

Submerged Arc Welding is mainly used for flat or horizontal welds because the flux employed in the process is susceptible to spill when it is being used for a vertical or overhead position. This restricts their viability to a great degree. Hence, submerged arc welding isn’t suitable for a wide range of projects needing flexible welding orientations.

Lack of Versatility

This is very effective for long, straight seams but works less well for short welds or more complicated shapes that require more precise methods of welding. This then restricts its use to only a few types of projects, thus reducing its overall versatility.

High Initial Investment

Setting up a Submerged Arc Welding operation can be quite costly. Equipment and materials required in the initial stages of setting up, such as automated feed systems and flux recovery units, are really expensive. This might be a factor that could discourage smaller-scale operations or those who are just getting their feet wet in the field.

Limited to Ferrous Metals

SAW is primarily used in the welding of steel and a few nickel-based alloys but is not suitable for metals like aluminum or copper. This means its use is considerably extended to projects dealing with ferrous materials.

Limited Accessibility

SAW equipment is bulky and complex, particularly when the setup is fully automated. This makes access for usage in places with confined or less accessible job sites quite difficult. It will reduce its effectiveness in a small or complex environment where space is a premium.

Cleaning and Waste Management

The process is relatively clean, but the residual flux and slag are a bit of a pain to handle. They have to be disposed of or recycled appropriately, adding to the operational overhead. This environmental/logistical consideration complicates project management.

Flux Handling and Maintenance

The maintenance of flux quality is as important as getting the qualified weld. It is not that easy to store or manipulate the flux to avoid its contamination and moisture; poor-quality flux can directly influence weld strength and integrity.

Calls for Thorough Setup

Indeed, SAW employs various variables like voltage, current as well as travel speed, among others in the attempt to replicate smooth and quality welds. This calls for great care on the course of setup and monitoring. Any error at the stage of setup can translate to poor welding which may not always be noticeable until after failure.

Thermal Distortion

SAW has generally lower levels of distortion compared to the other processes. However, very high heat input may generate warpage, especially in thinner materials. For this process, control means are generally necessary to prevent distortion, which usually involve extra time and cost.

Operator Safety

Even with less access to fumes and UV radiation, operators face physical workload associated with manipulation of heavy equipment and high temperatures. This represents a hazard that needs proper training and safety personal protective equipment.

Limited Operator Feedback

As the weld pool is beneath the flux, it is not possible to monitor the weld on formation by operators. This limits their capability to do real-time adjustment in the process or defect detection whenever such things occur. This could lead to late detection of problems, which would eventually affect the entire timeline and quality of the project.

The Bottom Line

Submerged arc welding has no equal in producing quality and efficient welds, especially for large-scale industrial applications with thick materials and involving long continuous seams.

Characterized by high deposition rates and deep penetration, and being automated, this ensures that projects are completed rapidly and with consistent weld quality, reducing time and saving costs accordingly.

The process does have its drawbacks: best suited for use in the flat or horizontal position, higher initial costs, and some material compatibility limitations. These are some things to consider in the selection of a welding process.

If your organization is looking for a balance between the pros and cons of submerged arc welding or if any expansion of facilities is going to take place where consultation with regard to implementing this technology into their process, then SENLISWELD has general welding solutions that cater exactly to such needs.

Contact SENLISWELD today for all your welding needs and ensure that your projects enjoy the highest level of efficiency and quality.

Submerged Arc Welding Advantages and Disadvantages