MIG to TIG: Exploring Types of Welding Techniques.

July 23, 2024

Welding is a fabrication process that involves joining materials, typically metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. There are different types of welding, how they are used and what they are used for, here are just a few:

Oxy-Fuel Welding – Also known as oxyacetylene welding is a process that may use a variety of gases (or combustible liquids), the most common being acetylene. Other gases may be used, such as propylene, liquified petroleum gas, propane, natural gas, hydrogen and MAPP gas.

In welding, the welder can adjust the oxyacetylene flame to be carburizing, neutral, or oxidising. These adjustments are made by adding more, or less oxygen to the acetylene flame.

• Neutral flame is the most used when welding and cutting. The neutral flame has a 1:1 ratio of acetylene and oxygen from the air which provides complete combustion. Neutral flame welding is most used for mild steel, cast iron, aluminium, copper, and stainless steel.
• Carburizing is a heat treatment process in which iron & steel absorbs carbon while the metal is heated in the presence of a carbon-bearing material, such as carbon monoxide. Carburizing is commonly used for, carbon steel, lead, aluminium alloys, and oxygen-free copper.
• Oxidizing flame has less acetylene and more oxygen, it is used for welding nonferrous metals like brass and copper.

Oxy-Gasoline torches can be used to cut through a steel plate up to 0.5inches (13mm) thick at the same rate as oxy-acetylene. Oxy-gasoline torches can also cut through paint, dirt, rust and other contaminating surface materials coating old steel. Operating costs are considerably less that oxy-acetylene and propane, typically around 75-90% less.

Diesel torches have several advantages over gasoline and gaseous fuels. Diesel is considered safer and stronger than gasoline and gaseous fuels such as acetylene and propane and will cut through steel faster and cheaper. This type of welding provides almost 100% oxidation during cutting, so it leaves almost no molten steel in the slag, preventing other materials to stick together.

Hydrogen is another gas used in the welding process as hydrogen has a clean flame and is best used with aluminium. Hydrogen can be used at higher pressures compared to acetylene, therefore is useful for underwater welding and cutting applications. Despite its underwater advantages, hydrogen is not used for welding steel and other ferrous materials as it can cause hydrogen embrittlement. For some oxy-hydrogen torches, oxygen and hydrogen are produced by electrolysis of mater, in an apparatus which is connected directly to the torch.

In oxyfuel cutting, a torch is used to heat metal to its kindling temperature. A stream of oxygen is then trained on the metal, burning it into metal oxide that flows from the cut as dross, the residual material left behind after cutting. Torches that don’t mix oxygen and fuel are not considered oxyfuel torches and can typically be identified by a single tank, as oxyfuel cutting requires two isolated supplies, the fuel and the oxygen which are contained within two separate cylinders, as well as two pressure regulators and two flexible hoses one for each cylinder and a torch.

Plasma cutting involves using a high-temperature, high velocity jet of ionized gas, called plasma, to melt and blow away material from the cut area. The plasma is generated inside of the plasma torch, where the electrical arc formed between an electrode and the workpiece. A compressed gas is forced through a small nozzle, and the arc ionizes the gas, turning it into plasma.

Arc Welding

Arc Welding is a welding process that joins metal to metal using electricity to create enough heat to melt metal and the melted metals, when cool, result in the binding of metals. A power supply creates an electrical arc between consumable and non-consumable electrode and the base material using either direct or alternating currents.

• Shielded Arc Welding – also known as stick welding, uses a consumable electrode coated with flux to lay the weld and is commonly used within construction.
• Gas Metal Arc Welding – also known as MIG (Metal Inert Gas) that uses a continuously fed wire electrode and shielding gas. MIG welding is popular within industrial settings due to its ease of use and efficiency.
• Flux-cored Arc Welding – Flux Cored Arc Welding is also known as FCAW, is a similar welding process to MIG welding, but uses tubular wire filled with flux and can be used with or without shielding gas. FCAW is generally used for applications outside and with thicker materials.
• Gas Tungsten Arc Welding – commonly known as Tungsten Inert Gas (TIG) welding, uses a non-consumable tungsten electrode and a separate filler material. TIG welding is known for producing high-quality, precise welds.
• Submerged Arc Welding – involves a continuously fed consumable electrode and a blanket of flux, which makes it suitable for long, straight welds.
• Electroslag Welding – is considered a highly efficient process of joining thick materials, providing strong, high-quality welds in a relatively short time. It is a process that is mostly used in heavy industries such as shipping and structural applications.

Laser Welding

Laser welding is a technique that uses concentrated beam of light to melt and fuse materials together. This is a precise process and if often used for applications requiring high quality. A laser beam is generated using a laser source, such as a solid state laser (Nd:YAG, fibre laser or a CO2 laser). The laser beam is focused on the joint, melting and fusing as it cools. The laser can be precisely controlled by adjusting the laser power, beam focus and weld speed.

Types of Laser Welding

• Keyhole Welding: The laser beam creates a keyhole within the material, which allows for a deeper penetration weld.
• Conduction Welding: The laser beam heats the material surface, causing melting and fusion without penetrating the surface. This type of weld is usually used for thinner materials.

Electron Beam Welding

Electron Beam Welding, also known as EBW is a high-precision welding process that uses a focuses beam of high velocity electrons to join materials. The kinetic energy of the electrons is converted into heat upon impact, causing the materials to fuse and melt together. The electrons are generated by an electron gun, typically using a tungsten filament. The electrons are accelerated to high speeds using high-voltage electric fields, ranging from 60-200kv.

EBW is usually performed within a vacuum chamber to prevent electron scattering by air molecules, ensuring precision and efficiency. The high density of the electron beams allows for deep penetration welds with minimal heat input, which reduces therm-

al distortion. This process offers precise control over the weld, making it ideal for delicate and high-precision applications.

Friction Welding

Friction welding is a solid-state welding process that joins materials using the heat generated from mechanical friction between a moving workpiece and a stationary one, which the addition of lateral force to produce a strong bond.

Types of Friction Welding

• Rotary Friction Welding – one workpiece is rotated while the other is held stationary. The rotating workpiece is pressed against the stationary one until sufficient heat is generated for bonding.
• Linear Friction Welding – one workpiece is moved back and forth in a linear motion while others remain stationary and is used for non-cylindrical parts and components.

Friction Stir Welding – is a rotating tool with a specially designed pin inserted into the joint line between two workpieces. The tool moves along the joint line, generating heat and stirring the material to form a bond. Commonly used for joining aluminium and other non-ferrous metals

Ultrasonic Welding

Ultrasonic welding is an industrial process in which high-frequency ultrasonic acoustic vibrations are locally applied to workpieces being help together locally under pressure to create a solid-state weld. It is commonly used for plastics and metals, and especially for dissimilar metals. In ultrasonic welding, there are no connective bolts, nails, soldering materials or adhesives necessary to bind materials together.

 

There are various types of welding, and their uses can vary depending on what application is needed. Welding is an efficient and useful process which allows for the fabrication of materials. Some types of welding are more useful than other, depending on its application, such as Electron Beam Welding, as it is mostly used for large scale projects such as ship building and construction whereas TIG & MIG welding are useful for smaller applications with steelwork and industrial settings.

fabrication Manchester. Metal Fabrication Sheet Metal Fabrication Stainless Steel steel structuralsteel welding