WELDING TYPES: ARC WELDING GUIDE

What Is Arc Welding?​

Like other welding types and fusion welding processes, arc welding is used to join metals. Arc welding does this by using an electric arc that creates an intense amount of heat, which melts metals and allows them to join together.

A power source is used to create this arc between an electrode and the base material, which melts them at the point of contact. Arc welding can use either a direct current (DC) or an alternating current (AC) in the process.

History and Development of Arc Welding

The history and development of arc welding trace back to the late 19th century, when advances in electricity and metallurgy paved the way for this groundbreaking technique. Arc welding, which uses an electric arc to melt and join metals, was first introduced in the 1880s by Russian inventor Nikolai Benardos. Over the decades, advancements like the introduction of coated electrodes in the early 20th century improved the process’s efficiency and quality. By World War II, arc welding had become a critical technique for shipbuilding and manufacturing due to its speed and ability to create strong, reliable joints. Today, arc welding has evolved into various specialized processes, including MIG, TIG, stick, and flux-cored arc welding, which are widely taught in professional programs like those offered by Universal Technical Institute (UTI).

Importance of Arc Welding in Modern Industries

Arc welding is essential to modern industries due to its versatility, efficiency and ability to create strong, durable joints. It supports various welding types where joining metal components is vital for producing buildings, bridges, vehicles and machinery. Arc welding encompasses different kinds of welding, including MIG, TIG, stick, and flux-cored arc welding, making it adaptable to various applications, from precision welding in aerospace to heavy-duty pipeline construction. These types of welds are taught in professional programs like those at UTI, equipping graduates with the skills needed to meet industry demands. The ability to perform different kinds of welding ensures arc welding remains an important part of modern industries.

How Does Arc Welding Work?​

The power generated in the arc welding process comes from either an AC or DC power supply. This creates a high amount of heat — around 6,500 degrees Fahrenheit! — which is hot enough to melt the base materials. To put that into perspective, that's more than twice as hot as lava flowing from a volcano!

The arc then gets formed between the work piece and electrode, which can either be a rod or wire that is guided manually along the joint connecting them. This can be guided either manually or mechanically.

The Science Behind the Arc Welding Process

The science behind arc welding lies in its ability to use an electric arc to generate intense heat, which melts and fuses metal parts together. The process begins when an electric current flows between the welding electrode and the workpiece, creating an arc that can reach temperatures of up to 10,000 degrees Fahrenheit. This heat melts the base metal and, in some cases, a filler material, which solidifies to form a strong joint as it cools.

Benefits and Limitations of Arc Welding

Arc welding offers many benefits, making it one of the most widely used welding types, but it also comes with certain limitations. One of its main advantages is its versatility, as it supports different kinds of welding processes like MIG, TIG, stick, and flux-cored arc welding, making it adaptable to a wide range of materials and applications. Arc welding is efficient, cost-effective and capable of producing strong, durable joints in everything from small precision parts to large structural projects. However, it does have limitations, such as requiring significant skill and training to master, as well as potential safety risks like exposure to high heat, ultraviolet radiation and fumes. Certain types of welds, like those used in high-stress or specialized environments, may require advanced techniques or equipment.

Equipment Used in Arc Welding​

A variety of equipment is used in the process of arc welding, including:

• Welding machine: Provides the power supply used for generating the heat necessary to the welding process.
• Electrode holders: Ensure electrodes are kept at the desired angle.
• Cables or leads: Carry current from the machine to the work.
• Cable connectors: Make a connection between machine switches and the electrode holder.
• Chipping hammer and wire brushes: Used to remove remaining particles or materials produced as a byproduct of the welding process.
• Protective clothing and face shield: Ultraviolet and infrared radiation is produced when welding, as well as sparks and heat. Protective clothing is worn, as well as a screen or shield to protect the eyes and face.

Types of Arc Welding

There are four main types of arc welding, all of which are taught in the Welding Technology program at Universal Technical Institute (UTI). They are:

• Gas metal arc (GMAW)
• Shielded metal arc (SMAW)
• Flux-cored arc (FCAW)
• Gas tungsten arc (GTAW)

Brian Masumoto, Welding Instructor at UTI Rancho Cucamonga, says UTI stands out when compared with most welding programs that concentrate on a specific process.

“Our experience isn’t limited to just one type of welding,” Masumoto says. “We cover all the major types of welding, which better prepares students for all different types of industries.¹ We don’t focus on just one process. The students learn and experience the different processes, which makes them better qualified for a job.”⁶

Let's take a closer look at the four main arc welding processes and how these different kinds of welding help keep the world running.

Essential Tools and Safety Gear

Essential tools and safety gear are vital for performing arc welding effectively and safely. Tools like welding machines, electrodes, clamps and wire feeders are necessary for creating different kinds of welding joints, while equipment like grinders and metal brushes help prepare surfaces for clean, strong welds. Safety gear is equally important, as arc welding produces high heat, intense light and harmful fumes. Welders need a welding helmet with a proper shade to protect their eyes and face from ultraviolet and infrared radiation, along with fire-resistant gloves and clothing to shield against sparks and heat. Other safety essentials include steel-toed boots, hearing protection, and a respirator or ventilation system to prevent exposure to harmful fumes.

Maintenance Tips for Welding Equipment

Proper maintenance of welding equipment is essential to ensure its performance and safety during use. Regularly inspecting cables, connectors and electrodes for wear or damage is crucial, as faulty components can affect the quality of the weld and pose safety risks. Cleaning welding machines and removing any dust, debris or metal particles can prevent overheating and ensure smooth operation. Checking gas flow systems, if applicable, and replacing filters as needed is important for processes like MIG and TIG welding. It's also vital to lubricate moving parts and follow the manufacturer’s guidelines for routine servicing. Calibration of settings, such as voltage and amperage, should be performed regularly to ensure consistent performance when creating different types of welds. By implementing these maintenance tips, welders can maximize the efficiency of their tools, reduce downtime and ensure reliable results across various welding types.

Gas Metal Arc Welding: GMAW

Gas metal arc welding (GMAW), also known as metal inert gas (MIG) welding, is a process when an electric arc forms between the electrode and metal to melt the metal pieces together.

GMAW is one of the most common welding processes and can be used indoors to weld materials for industries like construction, vehicle production, manufacturing and aerospace. It’s not recommended to use GMAW outdoors, since the wind can blow away the gas and damage the process.

GMAW welding produces minimal waste and isn’t prone to chipping. The process can be semi-automatic or fully automatic, which makes it simpler for welders because they don’t have to worry about defects on stops and starts.

Shielded Metal Arc Welding: SMAW

Shielded metal arc welding (SMAW) is a welding technique that can be used on all ferrous materials in all welding positions. Another name for SMAW is stick welding. A flux-coated electrode (which is a metal stick in an electrode holder) is connected to a power source and touches the base metal to produce the weld. The flux shields the electric arc to prevent contamination.

SMAW can be used to weld low- and high-alloy steels, carbon steel, cast iron and nickel alloys for industries like construction, shipbuilding and manufacturing. It can be done indoors and outdoors.

SMAW creates slag, a layer of byproduct that welders remove after welding to achieve a clean finish.

Flux-Cored Arc Welding: FCAW

Flux-cored arc welding (FCAW) uses a continuous hollow wire electrode with a flux compound that protects the weld pool by forming a gas. FCAW is ideal for outdoor welding and for welding on dirty or contaminated materials, since it doesn’t require an external shielding gas to protect the weld from atmospheric elements. Much like the SMAW process, FCAW also produces slag that is chipped off after the weld to give it a clean look.

FCAW is often used for thick materials because the flux-core wire can penetrate thick weld joints. FCAW isn’t appropriate for materials that are thinner than 20 gauge.

FCAW can be used on cast iron, stainless steel, carbon steel, high-nickel alloys and low-alloy steel. This welding technique is used in industries like construction and shipbuilding.

Gas Tungsten Arc Welding: GTAW

Gas tungsten arc welding (GTAW) is also known as TIG welding, which stands for tungsten inert gas. Just like in GMAW welding, an inert shielding gas is used. But unlike GMAW, which uses a wire that also acts as filler material, GTAW heats up objects by utilizing a tungsten electrode that delivers current to the welding arc. This welding arc melts the metal and creates a liquid pool. Filler rod can then be added if necessary to enhance the strength of the weld.

GTAW requires great precision, since the tungsten needs to avoid touching the work piece and materials can’t be overheated, otherwise cracks and other issues can occur. The benefits of GTAW include greater weld control and improved strength and quality of welds.

GTAW also results in chip-free welds for a clean look. It is most commonly used to weld thin material and can be used for ferrous or nonferrous metals like stainless steel, aluminum, copper, magnesium and titanium.

Comparing Different Arc Welding Methods

The number of different arc welding methods highlights how versatile it is and its ability to meet a variety of industrial needs. Methods like MIG (metal inert has) welding are ideal for quick, efficient welding on thin materials and are commonly used in manufacturing and automotive industries. TIG (tungsten inert gas) welding, on the other hand, is prized for its precision and clean results, making it suitable for high-quality welds on stainless steel and aluminum, often used in aerospace and decorative work. Stick welding, also known as shielded metal arc welding (SMAW), is versatile and effective for outdoor or rugged environments, as it performs well on thicker materials and is less sensitive to surface impurities. flux-cored arc welding (FCAW) is another method that excels in heavy-duty applications, such as structural and pipeline welding, due to its ability to handle thicker materials quickly. Each method offers unique advantages and limitations and selecting the right one depends on factors like material type, project scope and desired weld quality.

Learn About Welding at UTI

At UTI, students get to train with high-quality welding tools used in the professional world. Supportive instructors are there to answer questions and provide guidance. Students can graduate from the program in just 9-10 months.

Learn more about the UTI's Welding Technology program. Contact us for more information.