What Is Dual Shield Welding
Dual shield welding, also known as Flux Core Arc Welding (FCAW), is a welding procedure that uses an arc between the metal shields and the consumable anode to create a weld pool.
The pool is protected by a flux in the tubular anode, and an externally supplied gas provides additional protection.
This process is called double shielding.
Dual shield welding uses a dual shielded anode, which adds alloy elements to the weld puddle and generates a slag that covers the weld.
It is commonly used in the automobile and machine fabrication industries for welding thicker metals and out-of-position welds.
Did You Know?
1. Dual shield welding incorporates both a solid filler wire and a tubular flux-cored electrode, providing better control and deposition efficiency than conventional welding methods.
2. The flux in the tubular electrode of dual shield welding acts as a shielding gas, preventing atmospheric contamination and providing excellent weld quality even in outdoor or windy conditions.
3. Dual shield welding is particularly advantageous for welding thick materials, as the combination of the solid filler wire and tubular electrode produces higher deposition rates, reducing welding time.
4. The tubular flux-cored electrode in dual shield welding contains various alloying elements, allowing for enhanced strength, toughness, and resistance to corrosion in the resulting weld.
5. Dual shield welding is commonly used in industries such as shipbuilding, heavy machinery manufacturing, and pipeline construction due to its versatility, efficiency, and ability to produce high-quality welds in challenging environments.
What Is Dual Shield Welding?
Dual shield welding, also known as Flux Core Arc Welding (FCAW), is a welding procedure that utilizes an arc between the metal shields and the consumable anode to create a weld pool. This process is called double shielding as it involves both a flux core and an externally supplied gas for protection.
The flux in the tubular anode creates a protective barrier for the weld pool, while the externally supplied gas, typically carbon dioxide or a mixture of carbon dioxide and argon, provides additional shielding. The use of a dual shielded anode adds alloy elements to the weld puddle and generates a slag that covers the weld, further protecting it from oxidation.
Dual Shield Welding Procedure And Techniques
Dual shield welding is a welding process that involves melting the parent metal and the consumable filler wire together using the heat produced by an electric arc. There are two types of dual shield welding based on the protection technique:
- The first type relies on an external protection gas, which is typically provided from a high-pressure gas cylinder.
- The second type relies on the flux core itself to provide protection. The flux not only shields the weld metal but also generates a slag that further covers the weld.
The recommended polarity for dual shield welding is DC+.
In dual shield welding, cored, cannular anodes are preferred over solid wires due to their benefits. Dual shield welding is ideal for welding thicker metals and performing out-of-position welds. It can be used with various metals, including carbon steels, stainless steel, hard-facing alloys, and cast iron. However, it is not suitable for non-ferric metals like aluminum.
To transform a MIG welding machine for flux core arc welding, the rollers need to be changed to a suitable size and the tension settings adjusted.
Dual shield welding offers two types of metal transfer:
- Globular transfer: This involves the filling material forming large drops that detach from the filler wire and fall into the weld pool.
- Spray transfer: This is the most commonly used transfer type, where the filler metal is sprayed onto the joint.
Key points:
- Dual shield welding uses an external protection gas or flux core for protection.
- Cored, cannular anodes are preferred over solid wires.
- Suitable for welding thicker metals and performing out-of-position welds.
- Works with carbon steels, stainless steel, hard-facing alloys, and cast iron.
- Not suitable for non-ferric metals like aluminum.
- MIG welding machine can be transformed for flux core arc welding.
- Dual shield welding offers globular and spray metal transfer types.
Advantages And Applications Of Dual Shield Welding
Dual shield welding is a highly advantageous welding procedure that is widely used in various industries. Compared to other welding procedures, it offers numerous benefits such as producing welds with more consistent mechanical characteristics and fewer faults.
One of the key advantages of dual shield welding is its ability to provide higher production rates and portability, which makes it suitable for outdoor welding applications. This is particularly beneficial in industries like the automobile industry and machine fabrication industries where welding needs to be done in different locations.
Additionally, dual shield welding is particularly useful for thicker materials and out-of-position welds. It can be utilized for a wide range of metals including carbon steels, stainless steel, cast iron, and hard-facing alloys.
Another advantage of dual shield welding is its enhanced arc stability and higher deposition rates. This contributes to the efficiency of the welding process and ensures high-quality welds.
Furthermore, dual shield welding is considered an “all-position” welding procedure, meaning it can be used in various positions without compromising the quality of the weld. This makes it a versatile and practical choice for many welding applications.
Lastly, dual shield welding requires less expertise compared to other welding procedures. This means that even individuals with less welding experience can effectively perform dual shield welding.
Tips And Considerations For Dual Shield Welding
To enhance weld seams in flux core arc welding, it is recommended to:
- wipe off slag after every pass
- pull the gun for backhand welds
- maintain a quick travel velocity for overhead welds
For dual shield welding:
- The anode polarity needs to be negative
- Knurled drive rolls are recommended over sleek drive rolls
For vertical welds:
- The angle of the weld can be adjusted
When welding thicker metals:
- It is important to adjust the parameters on the welding appliance down by 10 to 15%
- Remove slag formation before depositing subsequent layers
Some important considerations:
- Dual shield welding is not suitable for materials thinner than 20 gauges
- Welding both sides of a joint is recommended for a stronger joint
- Proper handling and storage of dual shield welding electrodes is necessary
- Cost-wise, the filler material used in dual shield welding can be more expensive than solid wire anodes. Therefore, it is vital to ensure the right filler material is used and that there is a constant and proper wire feeding throughout the welding process.
Dual Shield Welding Vs. Other Welding Procedures
Dual shield welding offers unique advantages and has distinct differences compared to other welding procedures.
- Unlike MIG welding, dual shield welding does not require a shielding gas tank, making it suitable when a gas tank is not available.
- It is a productive procedure and is ideal for working with thicker joints.
- In contrast, MIG welding, which utilizes a shielding gas, is better suited for thinner metals such as stainless steel, aluminum, and steel.
- MIG welding produces high-strength welds that provide an excellent appearance.
Furthermore, dual shield welding is similar to flux core welding as both involve hollow tubular wires.
- However, flux core welding requires a shielding gas and relies on gas generated from the wire’s flux.
- Dual shield welding can be performed with or without the use of a protective gas, similar to MAG welding.
- Nonetheless, dual shield welding is advantageous for outdoor use, as it has built-in shielding and can withstand strong breezes.
In conclusion, dual shield welding, or Flux Core Arc Welding, is a versatile welding procedure that offers advantages such as enhanced mechanical characteristics, high deposition rates, and suitability for thicker materials.
- It finds applications in industries such as automobile and machine fabrication.
- By following proper techniques and considering various factors, welders can achieve strong and reliable joints using this welding process.
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Frequently Asked Questions
What is a dual shield welder?
A dual shield welder is a type of welding equipment that is specifically designed for flux cored arc welding (FCAW). It is a semi-automatic welding process similar to metal active gas (MAG) welding, using a continuous wire fed electrode and a constant-voltage welding power supply. The term “dual shield” refers to the use of two shielding methods during the welding process. One shield is provided by the flux inside the electrode itself, while the other shield is generated externally using a shielding gas, usually a mixture of carbon dioxide and argon. This combination of shielding methods helps to protect the weld from contamination and produces strong, high-quality welds.
What are the advantages of dual shield welding?
Dual Shield welding offers several advantages when it comes to joint design and weld metal consumption. Firstly, the small diameter and deep penetration of the Dual Shield flux-cored wire electrodes allow for a decrease in the included angle and root opening of a joint. This means that joints can be formed with tighter designs, resulting in stronger and more secure welds.
Additionally, the use of Dual Shield welding reduces the volume of weld metal needed to fill the joint. As a result, there is a significant reduction in the amount of consumables required for welding. This not only helps to minimize costs but also allows for faster welding speeds, increasing overall productivity. Overall, the advantages of Dual Shield welding lie in its ability to improve joint designs, enhance weld quality, and optimize resource utilization.
Can you run dual shield without gas?
Running dual shield without gas is not possible due to the lack of shielding provided by the flux. While the flux in dual shield wire improves deposition rates and weld characteristics, it does not shield the weld. Gas is required to provide a protective atmosphere and prevent contamination. On the other hand, using regular flux core with gas is a viable option as the flux core itself provides the necessary shielding. However, it’s important to note that dual shield cannot be used without gas for proper weld protection.
What is a dual welder?
A dual welder is a type of welder that has the ability to support two operators simultaneously. These welders are equipped with powerful diesel engines that not only provide enough power for two welding arcs, but also have the capacity to operate additional welding power sources. This means that operators can work independently on different welding projects using different welding machines, increasing productivity and efficiency in a variety of welding applications. Whether it’s the XMT® 350, CST™ 280, or PipeWorx 350 FieldPro™, a dual-welder is a versatile tool that offers powerful capabilities for multiple operators.