The 12 Main Types of Welding: What they are use for?

Welding is a manufacturing process that uses heat, pressure, or both to join two or more materials into a strong, permanent bond. Materials commonly welded are metals and thermoplastics, but other materials, such as wood, can also be welded.

This is a key process in most industries. Let's examine how it works and the underlying knowledge that supports it.

How is welding performed?

Welding is a high-temperature process that melts the base metal. This is the key difference from brazing and soldering, which only melt the filler material and do not fuse the base metals.

Welding joins two or more workpieces at high temperatures. The high temperature creates a molten pool, which cools and solidifies into a single, solid body, forming a weld. The weld can be even stronger than the base metals.

There are many types of welding, but all use heat or pressure to melt the metals and form the weld joint. The source of heat or pressure may vary depending on the application and the materials used. Due to the simple and well-understood principles of welding, metals are considered the most commonly welded materials. Plastic welding is also quite common, while wood welding is just beginning to gain traction.

The welding process is influenced by a variety of factors, such as the need for specific tools, shielding gases, electrodes, and filler materials. Let's take a closer look at some of the most commonly used welding methods and identify their unique characteristics.

Different Types of Welding

While the basic concept of welding is relatively simple, it can be categorized based on the energy source used. As we further break down these subcategories, we can delve deeper into the operating principles behind each method.

Arc Welding

Arc welding is a welding process that uses the arc heat generated between the electrode and the workpiece to locally melt the metal and filler wire (or no filler) to connect the materials. Arc welding electrodes are either consumable or non-consumable. Both alternating current (AC) and direct current (DC) can be used during welding.

1.MIG/MAG Welding

Gas metal arc welding (GMAW), also known as MIG/MAG welding (metal inert gas/metal active gas), uses a continuous wire fed through a welding torch. As the arc melts the wire, it fuses with the base metal in the weld pool.

Simultaneously, a shielding gas is supplied to the weld area, creating a protective barrier to prevent atmospheric contamination.

This welding technique is easy to use. That's why it’s a popular choice in industrial welding, manufacturing, construction, and automotive industries. Due to the availability of inexpensive inert gases, gas metal arc welding (GMAW) has largely replaced atomic hydrogen welding (AHW).

2.TIG Welding

Tungsten inert gas welding (TIG) uses a non-consumable tungsten electrode and an inert shielding gas. Unlike MIG/MAG welding, the use of a separate filler metal in TIG welding can be determined based on project requirements. Gas tungsten arc welding (GTAW) creates precise, high-quality welds. It offers excellent penetration. This makes it great for many uses, like aerospace and automotive. At the same time, TIG welders have many adjustable features. This makes TIG a very versatile welding process.

3.Stick Metal Arc Welding

Sticky Metal Arc Welding (SMAW), also known as manual metal arc welding (MMAW/MMA) or stick welding, uses a consumable flux-coated metal electrode to join metals.

When the electrode strikes the base metal, an arc is generated, melting the material in the weld pool. The flux releases a shielding gas, protecting the weld metal from contamination. After cooling, slag can be removed with common tools such as wire brushes.

4.Flux-Cored Arc Welding

Flux-cored arc welding (FCAW) is a welding process that is typically automated or semi-automated and can reduce welding time by up to 40% compared to traditional manual welding.

FCAW uses a flux-cored electrode to protect the weld. Additionally, double-shielded FCAW provides additional protection against contaminants by using a shielding gas over the flux-cored electrode.Compared with some other welding methods, FCAW does not require additional gas shielding equipment (especially double shielded welding), so in the long run, the cost of equipment and materials can be greatly reduced.

5.Gas Welding

Gas welding, also known as oxy-fuel welding, is one of the most traditional methods of joining metals, using a combination of oxygen and a fuel gas such as acetylene or propane. This process generates intense heat that melts the metal at the joint, allowing it to fuse together. It is commonly used for both ferrous and non-ferrous metals, and is especially effective for thin materials.

One of the key advantages of gas welding is that it does not require electricity, making it a highly portable solution in areas with limited power access. The equipment is relatively simple to operate and costs less than other welding methods, making it a popular choice for small-scale and DIY projects. Gas welding can also be used for oxy-fuel cutting, offering versatility with the same equipment.

Despite being an older method, gas welding remains effective for many applications. Its ability to adjust the flame profile by regulating gas flow allows for precise control, making it suitable for delicate tasks like brazing and welding thin sheets of metal. It's a reliable and accessible technique for various metalworking needs.

6.Plasma Welding

Plasma arc welding operates on a similar principle to TIG welding, but its unique torch design allows inert gas to be ejected from the nozzle at a higher velocity, flowing along a narrower path. When the gas comes into contact with the arc, plasma is formed and ionized as it enters the weld zone, generating extremely high temperatures. This allows welding temperatures to reach approximately 28,000°C, high enough to melt nearly any metal.

Because plasma arc torches can generate such high operating temperatures, they are suitable not only for precision welding but also for metal cutting. During the welding process, the plasma arc provides highly concentrated heat, resulting in finer welds and faster welding speeds, making it particularly well-suited for metalworking requiring high precision and complex structures.

7.Submerged Arc Welding

Submerged arc welding (SAW) operates on a similar principle to sticky metal arc welding (SMAW), using flux to protect the weld metal. This automated or semi-automated welding process uses a separate flux hopper to deposit granular filler metal onto the weld.

This welding technique produces consistent, clean welds that outperform most traditional manual welding processes. It is an excellent choice for metals such as nickel, steel, and stainless steel and is commonly used in the fabrication of pipes, pressure vessels, and boilers.

Resistance Welding

Resistance welding, or pressure welding, involves applying pressure and an electric current between two metal surfaces to create a fusion bond. The workpieces are brought together under high pressure, and an electric current is passed through the contact points. The resistance in the metal generates heat, fusing the metal surfaces together.

1.Spot Welding

Resistance spot welding (RSW) uses two electrodes to press overlapping metals together while simultaneously applying a welding current through the resistance of the metals. Heat is generated during the welding process, causing the metal surfaces to fuse together, forming a button-shaped or nugget-shaped weld.

The metals fuse together at high energy in a short time (approximately 10-100 milliseconds), joining the workpieces almost instantly. The area surrounding the weld is not damaged by the excessive heat, resulting in a minimal heat-affected zone (HAZ) in spot welding.

Spot welding is often automated using welding robots. This makes it one of the most efficient welding methods used on assembly lines, making it an attractive option for the automotive, electronics, and manufacturing industries.

2.Seam Welding

Seam welding is a type of spot welding. It uses two electrode wheels to press down on the workpieces. At the same time, current flows through them. The welder can use power in two ways. It can apply power intermittently to make individual welds on the workpieces. Or, it can apply power continuously, based on the project needs.

Resistance seam welding produces very tight joints, and the weld process is extremely fast and clean, making it ideal for automated welding. The sheet metal industry uses seam welding to manufacture tin cans, radiators, and steel drums.

Laser Welding

Laser welding (LBW), as the name suggests, uses a laser beam as a concentrated heat source to melt metal and form the weld. LBW's high power density results in a smaller heat-affected zone. Laser spot sizes range from 0.2 to 13 mm, making it suitable for welding materials of varying thicknesses and achieving superior results compared to traditional welding processes.

Laser welding can quickly produce high-quality welds within tight tolerances. The process is often automated and widely used in the automotive, medical, and jewelry industries.

Some people think laser torches can cut and weld like oxy-fuel and plasma torches. However, this is usually not true. Standard laser cutting heads cannot be used for welding, and laser welding heads cannot meet the cutting speed and quality requirements of most industrial applications.

Electron Beam Welding

Electron Beam Welding (EBW) is a high-precision welding technique that uses a focused beam of high-energy electrons to melt and join metal surfaces. The electrons are accelerated in a vacuum and directed onto the workpieces, generating intense heat at the weld site. The process occurs in a vacuum environment, preventing oxidation and contamination.

One of the main advantages of EBW is its ability to produce deep, narrow welds with minimal heat distortion. This makes it ideal for high-precision applications, such as aerospace and medical device manufacturing. The process also allows for welding of dissimilar metals and produces high-strength joints with excellent weld quality and minimal post-weld processing.

Friction Welding

Friction welding is a solid-state welding process that, as the name suggests, uses friction to fuse metals together. Unlike most welding processes, it does not use a welding gun, welding rod, or shielding gas. The process creates a joint using heat generated solely by high-speed rotation, vibration, or lateral contact between two clean pieces of metal. Metal residue formed during the process is removed after cooling.

The welding equipment used for friction welding is more environmentally friendly than other methods because it does not emit harmful welding fumes or toxins. Its ease of operation makes it ideal for welding drill bits, connecting rods, shaft tubes, and valves.

Welding Safety

Welding safety is a top priority for every welder. Proper safety gear, such as welding masks, flame-resistant gloves, protective clothing, and safety boots, effectively protect against heat, UV radiation, sparks, and hazardous gases. Welding masks, in particular, not only protect the eyes from arc damage but also reduce the inhalation of harmful gases, safeguarding respiratory health. Furthermore, earplugs and ear defenders are essential when welding to mitigate noise damage to hearing.

However, safety gear is only one part of welding safety; welders' safety awareness is equally crucial. The complexity of the welding process requires welders to possess a high level of responsibility and a keen awareness of risks. They must have a clear understanding of the operating environment, equipment status, and emergency procedures. Welders must always ensure adequate ventilation in their work area to prevent the accumulation of harmful gases and regularly inspect their equipment to prevent malfunctions.

Summary

Welding technology connects metal to metal, achieving effects not possible with individual metal parts. With the continuous advancement of technology, welding technology continues to innovate and develop. In the future, welding processes will become more intelligent and efficient, with automated and robotic welding becoming mainstream, improving production efficiency and reducing human error. At the same time, the emergence of new welding materials and processes will expand applications, bringing higher-quality, more environmentally friendly welding solutions to industries such as aviation, automotive, and energy.