The heart of the flux-cored arc welding process is the tubular wire electrode that makes the FCAW process fundamentally different from MIG. Rather than just conducting an electric arc and providing filler to the molten weld pool, the tubular construction of the flux-cored wires allows it to be packed with slag formers similar in nature to those found on the outside of stick electrodes used for SMAW.
Whether the wire is designed for use with external shielding gas (an FCAW-G wire) or without (an FCAW-S wire), the core of these flux cored wires must serve double (and sometimes) triple-duty. They can alloy the weld pool and remove impurities to help improve the strength and toughness of the completed weld. Impurities are removed from the weld pool through slag formation, but the slag also helps support and shape the solidifying weld metal.
In short, the slag is what makes the process unique and provides flux cored arc welding with unique benefits for a wide range of applications.
Application One: Outdoor Structural Welding
Gas-shielded processes such as MIG are not generally recommended when the wind speed in the area of welding exceeds 5 miles per hour. However, when the weather is not cooperating with a pressing deadline, or maybe you are working in an offshore location, self-shielded flux-cored electrodes are the most economical means of completing critical welding jobs. Unlike gas-shielded wires, self-shielded wires can generate a sufficient volume of atmosphere-displacing gas to maintain weld quality even when the wind picks up.
But a porosity-free weld is only part of what makes the self-shielded flux cored electrodes a staple on construction sites nationwide. Wires intended for heavy-duty applications such as bridge and skyscraper erection need specially designed wires that provide excellent mechanical properties such as toughness to resist many natural and artificial forces. With one of these tough flux-cored wires and a well-designed welding procedure, it is possible to quickly and economically deposit weld metal on demand or fracture-critical structural components such as seismic-force restraint systems.
Of course, only some applications consist of splicing columns and making moment connections that exceed several inches in thickness. For those other applications, the modern “seismic” flux-cored wire is often too large in diameter for thinner materials and undoubtedly not as user-friendly.
To meet the needs of repairs around the home and farm, self-shielded flux cored wires exist that are smaller in diameter and easier to be successfully wielded by a broader range of skill levels. Like their large-diameter counterparts, these wires are still suitable for being brought to the outdoor workpiece. Still, the smaller diameter makes welding thinner materials, such as fencing, much easier with less risk of burn-through.
Application Three: Out-of-Position Welding
Flux-cored wires also can facilitate high-quality welding “out-of-position.” Not all welds can be easily made “in-position” with the weld joint resting on the workbench. In the production environment, it can be economical to invest in equipment that helps to allow easy movement of the workpiece to “position” parts. Still, for complex weldments, this may be a luxury.
Flux-cored wires have a unique advantage of a slag that solidifies to support molten metal when welding in the vertical and overhead positions. With high-quality welding wire and good technique, it is possible to produce very flat welds that can be difficult to distinguish from in-position welds.
It is possible to use MIG to weld out-of-position, but both deposition rate (productivity) and weld penetration will suffer compared to those all-position flux cored wires.
Unfortunately, not all flux-cored wires are suitable for welding out-of-position, but those that can are often classified and marketed as such. Wires intended for in-position welding only are often available in larger diameters and have a slower freezing slag that allows for high-amperage welding parameters to achieve the highest travel speeds.
Application Four: Rust, Scale, and Weldable Primer
Those who weld within the construction industry, know that bridges and skyscrapers start in the beam fabrication shop, where steel webs and flanges are joined into structural shapes such as angle, channel, and I-beams. Although every shop is different, many beam fabricators perform work in enclosed structures. However, raw materials are often stored in outdoor locations with at least some environmental exposure that leads to rust or necessitates the benefits of mill scale and weldable primer.
Although removing all potential contaminants from the base metal is “best practice,” it often becomes complicated to justify in the production environment as the part size increases. To maintain control of productivity and profitability, leveraging the welding process itself can be helpful. Remember that the slag of the flux-cored welding process helps to remove impurities from the weld metal to maintain good weld quality.
Application Five: The Heavy Duty
FCAW manufactures various components ranging from consumer goods to refinery components. Each of these applications demands different weld deposit chemical compositions to ensure the welds perform satisfactorily. Just as you can purchase wires for welding indoors or outdoors, or out-of-position versus in-position only, flux-cored wires are available in compositions ranging from carbon and low-alloy steel to nickel super-alloys and everything in between.
The flux-cored wire market is vast, meaning there are plenty of wires to choose from. However, if you are considering selecting flux-cored arc welding for your particular application, first consider the following:
Will you be welding outdoors? If so, you may benefit from a self-shielded flux-cored wire. If not, a gas-shielded flux-cored wire may still help tackle dirty base material with less prep work.
Will you be welding out-of-position? If so, you may benefit from an all-position flux-cored wire. Even still, large-diameter gas-shielded flux-cored wires can achieve deposition rates challenging to obtain with MIG.
What kind of mechanical property requirements does your application demand? Chances are good that a flux-cored wire exists that will help you strike the best balance between optimal properties and productivity.
If you’re still unsure, reach out to the Red-D-Arc team! We have extensive experience with applications of flux cored arc welding ranging from field to shop. Contact us today to learn more and select the rental equipment you need to complete your job today!
The construction industry is responsible for the creation of all kinds of structures with varying sizes, levels of complexity, and uses. From simple, small structures such as family homes to large, complex ones like bridges, dams, and manufacturing plants. Structural integrity and durability are the most important considerations in this industry. This is why the construction industry employs a very large quantity of metals. In the United States alone, more than 40 million tons of steel are used annually in the construction industry. The majority of this quantity is used to create structural frameworks. This is where welding plays an indispensable role in construction.
Welding technologies are widely used in the construction industry, mainly for the fabrication of structurally sound metal frameworks by fusing various metals components. It is also used to create and maintain non-structural components. Some of the welding used for construction is pre-fabricated in a shop environment while other parts of the welding process are done on-site.
Applications of Welding in Construction
Construction comprises numerous industries, including transportation, oil, andgas, telecommunication, power, manufacturing, many others. The construction industry is very broad & diverse and is divided into three major sectors which differ by the type of structures they create. These sectors are Building, Infrastructure, and Industrial.
The application of welding is crucial to all three sectors.
As the name suggests, the building construction sector involves the creation of structures in which people can dwell and carry out their activities. This sector is further divided into residential and non-residential. Building construction mainly employs welding in the creation of structural frameworks from metal components. Welding is used for connecting steel I-beams, trusses, columns, and footers, to support the walls, roof, and floors of a building. These components are cut to shape and size, lifted into position, and welded together.
Structural welding is not employed as extensively in small buildings, as it is in high-rise buildings that require thousands of metal joints. Welding in building construction is also used for the fabrication of non-structural building components such as firewalls, stairs, handrails, and floor joists. Furthermore, welders work with other professionals in setting up various systems in a building. These include:
Electrical systems – creating electrical conduits Construction for laying wires.
Plumbing systems – installing water supply and wastewater drainage pipes.
Ventilation systems – installation of vents and ventilation pipes.
Fuel systems – installation of gas supply pipes.
This sector is responsible for the creation of infrastructures such as bridges, dams, railways, stadia, water supply systems, highways, and wastewater management systems. The application of welding in infrastructure construction is mainly structural. This is because most of the structures created in this sector are megastructures that completely depend on structural reliable metal frameworks created via welding. Certain infrastructure such as bridges can be made almost entirely of metal. Others such as dams and water systems require a lot of pipe welding.
Industrial construction covers all structures that are utilized industrially. Structures created by this sector hardly stand alone but are usually part of a large system of numerous components and structures that work together for specific purposes. Such systems include manufacturing plants, refineries, mills, power generation stations, and many more. Industrial construction is considered the most diverse sector within the field as it cuts across numerous industries. The applications of welding in this sector are as diverse as the sector itself. TIG welders are used for the fabrication and maintenance of structural frameworks, pipelines, industrial equipment, and support structures for large components.
Welding Technologies Employed in the Construction Industry
The construction industry has a wide range of welding needs. Most existing welding technologies have one use or the other in the industry. Some of these and their uses are as follows:
SMAW: Also known as arc welding, submerged metal arc welding (SMAW) is mainly used for welding steel structures.
FCAW: Flux-cored arc welding is considered more convenient than its submerged arc counterpart. This technology is widely employed in fabrication using structural steel as well as heavy equipment repair
GTAW: Gas tungsten arc welding (GTAW), also known as TIG welding, is crucial for its compatibility with various metals including stainless steel, aluminum, bronze, and copper.
GMAW: Gas metal arc welding (GMAW), popularly known as MIG welding, is employed for both structural and non-structural purposes.
Application-specific welding systems employed in the construction industry include stud welders such as ProWeld Arc and pipe welders such as the PipeWorx welding system.
Benefits of Welding in the Construction Industry
The importance of structural integrity and durability in construction can hardly be overemphasized as structural failure can lead to a devastating loss of life and resources. Structures created weigh thousands of tons and are expected to last for hundreds of years. With the high strength and durability of weld joints, stakeholders in construction can rest assured that there’s nothing to worry about from the point of the framework.
Productivity is crucial to saving costs, resources, and time on any construction project. Productivity in a project is dependent on the efficiency of the processes involved. In terms of advancing construction efficiency, welding is at the forefront. While welding itself is a highly efficient process when using the right equipment, several other technologies have been incorporated into the process to make it even more efficient. Some of the technologies used in welding that are particularly beneficial to the construction industry are as follows:
This technology saves builders thousands of dollars and increases speed and productivity by eliminating the need for a welder to move to and from a power source to make necessary adjustments during welding. This is particularly helpful in high altitude welding where the actual welding may be 100s of meters above the ground where the power source is located. Some of the solutions that make up ArcReach include Cable Length Compensation (CLC™) which automatically adjusts the delivered voltage based on the cable length to ensure that the set voltage is always supplied; and Adjust While Welding (AWW™), which allows the operator to remotely adjust weld settings right from where they are working.
Weld Automation Equipment
Types of automation equipment that increase efficiency and accuracy include automatic wire feeders, welding manipulators, turning rolls, and welding positioners which are used to hold and rotate the pipe or other weldment.
Multiprocess TIG Welders
Some welding projects require more than one welding technology at a spot. It is stressful enough to switch equipment not to imagine doing this at heights where you would need to ascend and descend repeatedly. Multi-process welders eliminate this problem by combining various welding technologies into a single compact unit. In addition to all these, another factor that boosts productivity is the portability of welding equipment. This is appreciated when work has to be carried out over rugged terrain, at height, or in relatively small spaces.
The construction industry has a wide range of fabrication requirements. One of the numerous reasons why welding is indispensable in construction is its flexibility. For any size, work environment, or material, there is a suitable welding technique. For example, 5 cm diameter pipes can be welded as good as 50 m long beams and columns. Also, the various metal grades used in construction are all compatible with one welding technology or another.
Compared to many other manufacturing processes, welding is relatively cost-effective. To save even more, contractors and other industry stakeholders can simply rent high-quality TIG welders equipment, saving thousands of dollars on capital spending. If you are considering long-term continuous use, leasing your welding equipment might be an option to consider. Speak to one of our sales associates to learn more about our leasing programs and national accounts.
Tungsten electrodes are used in Tungsten Inert Gas (TIG) welding or plasma welding to join various types of metals. The electrodes are nonconsumable and come in a variety of sizes and lengths, and can be composed of pure tungsten or an alloy of tungsten and other rare-earth elements and oxides. The choice of electrode depends on the base material type and thickness, and whether you weld with alternating current (AC) or direct current (DC). The electrodes can be color-coded to eliminate confusion over their type, with pure tungsten electrodes being green. TIG welding creates clean, precise welds and is ideal for welding thin materials and surfaces that will be visible
To begin with, different electrodes have different colored bands that are used to identify them. However, there are several other important differences to consider when selecting a tungsten electrode. Here some of the various types with the respective characteristics: (more…)
How do I prevent wire feeding problems when using MIG welders (GMAW) or flux-cored arc welding (FCAW) processes?
Wire feed problems with a MIG welder can be caused by a variety of circumstances. Some of the most common reasons for wire feeding issues include:
Drive roll tension with the MIG Welder: The drive rolls that push or pull the wire through the system have a tension that is either too great or too little. Adjust the spring pressure until the tension is appropriate.
Drive roll size: The drive rolls may be the wrong size. For instance, if 1.3 mm drive rolls are being used to move 0.9 mm wire, slipping will most likely occur.
Drive roll type: Some wire requires specific kinds of grooves for optimal feeding. Flux-cored and metal-cored arc welding wires typically require V-groove drive rolls that are knurled. Aluminum wires require a smooth U-shaped groove.
Drive roll condition: Worn drive rolls will be ineffective at moving a wire through the MIG welder system.
Liner size: If a liner is too small for the wire it will not feed. If the liner is too big, the wire may have too much freedom to twist inside of it, causing an unpredictable feed.
Liner type: For most wires, steel liners work excellent. However, some wires, such as aluminum, require a nylon liner to help ensure proper feeding.
Liner condition: A worn liner will be detrimental to wire feeding. Replace the liner if it is worn or damaged.
Contact tip size: A proper contact tip size should be used. If the tip is too small, the wire will not feed; if the tip is too large, wire feeding and electrical conductivity may be negatively affected.
Wire condition: Not all wire manufacturers put out the same quality product. Some wires may have thin and thick spots as well as lubricants that can cause poor wire feeding.
The Millermatic 252 —sometimes referred to as the Miller 252— is an extremely popular and easy to use welder. You only need to see the reviews quoted on Miller’s product site to see how much those who use this welder like it. It can be used for metal fabrication, maintenance and repair, farm and home use as well as light industrial applications.
Capable of MIG (GMAW), Wirefeed, and Flux-Cored Welding (FCAW),this machine employs Active Arc Stabilizer technology which creates consistent power output resulting in better quality welds. The push/pull gun connects directly to the unit with no extra module required in between.
The unit detects the gun automatically and recalls the voltage, wire feed speed and timer of the active gun. There’s a panel on the front of the unit with a quick-reference parameter chart so you can quickly apply the correct settings for the consumables you are using. This welder has the highest output in its class (250 A at 28 VDC) allowing longer welding times on high-end applications. This is a very popular unit, praised for its ease of use by people who are learning to weld, hobbyists and others for whom welding is only one of many tasks they perform in a day. One user says that he taught his entire family to weld using this machine, including his 57 year old mother. Feature rich, well thought out, and easy to use, you would be hard pressed to find a better welder than the Millermatic 252.
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