What Is Welding? Types, Uses, Equipment, and How It Differs from Fabrication

Welding is one of the largest contributing factors to the growth of the construction industry and manufacturing sector. As stated by the American Welding Society (AWS), welding is involved in approximately half of all U.S. Manufactured products.

Many individuals have been exposed to welding; however, few people actually know the details about how welding operates or what distinguishes welding from other metalworking trades, including fabrication. Although these two terms are sometimes associated with one another, they do not refer to the exact same activity.

What is Welding?

Welding is defined as the process of fusing two or more items of material together (usually metal), using either heat, pressure, or both to produce a permanent union. 

In numerous welding methods, the base metals are heated to a melting point. If desired, a filler metal is then added to enhance the strength of the weld. 

After cooling, the weld connection is now a single item of material.

Examples of common welded materials:

• Carbon steel

• Stainless steel

• Aluminum

• Cast iron

• Copper

Explanation of the Welding Process

Regardless of the method of welding, the fundamental principle behind most welding processes is identical. 

First, the base materials must be properly cleaned and positioned relative to one another. Next, heat is applied via electrical current from an electric arc, flame, laser, friction or other energy sources. 

As the base metal heats up, a molten weld pool is developed where the pieces being joined are located. Depending on the welding process, filler metal may be added to provide additional reinforcement of the weld. Additionally, fluxes or shielding gases may be used to protect the weld area from contaminants.

After the molten weld metal has been allowed to cool and solidify, the result is a permanent weld connection.

Main Types of Welding

MIG welding (metal inert gas)

While all welding processes require experience and time to master, MIG welding is generally considered to be one of the easiest processes for novice welders to learn due to its rapid production rate and ease of use. 

MIG welding utilizes a continuous feed of wire electrode and shielding gas. Upon activating the trigger button of the welding machine, a constant flow of wire is fed through the welding gun while simultaneously producing an electric arc that melts both the wire electrode and base metal together. Shielding gas is introduced to protect the weld area from contamination.

As the continuous feeding of wire eliminates manual handling requirements, MIG welding can be faster and simpler to operate than other methods. 

Due to this advantage, MIG welding is widely used in fabrication shops, auto body repair shops, general repair work and in mass production environments.

Stick Welding (shielded metal arc welding)

Stick Welding is typically referred to as one of the most flexible welding methods.

Stick Welding utilizes an electrode rod with a flux coating. During application, the rod produces an electric arc causing both the rod and base metal to melt. During this melting process, the flux coating of the rod produces a gas and slag cover over the weld. 

One advantage of this process is that it does not depend on a shielded gas tank so it is ideal for outdoor welding and/or those situations where working conditions are harsh.

TIG Welding (tungsten inert gas)

TIG Welding is extremely versatile but often considered one of the most challenging welding techniques for individuals new to welding since it requires great coordination, control and precision.

Unlike MIG welding; TIG Welding utilizes a tungsten electrode rather than melting the electrode itself. Therefore, tig welders manually manage the movement of the torch with one hand while introducing filler metal with their second hand. A shielding gas surrounds the weld area throughout the entire process.

Since manual management of the torch affords welders greater control over the position and orientation of the arc, TIG Welding provides superior cleanliness as well as accuracy particularly when working with thin metals.

Flux-cored welding

Flux-cored welding resembles MIG welding since it involves feeding a continuous wire through a welding gun. However, unlike solid wires used in MIG welding processes, flux-cored welding utilizes a hollow wire containing a flux. As the flux core melts, it generates a shielding gas around the weld preventing contamination. Some variations also employ external shielding gases.

Flux-cored welding is commonly used for thick materials (like pipes and structural components), outside environments (where dust and moisture would compromise other processes), or demanding applications requiring high-speed deposition rates. Therefore, flux-cored welding is prevalent within construction, large-scale fabrication, outdoor operations and industrial projects.

Common Welding Joint Types

When referring to positioning two pieces of metal prior to joining them with a weld, this is known as a "joint". 

Different positions will affect weld strength; fit-up; material consumption; operation sequence for welding. Some joints are designed for carrying heavy loads; others are intended for light fabrication; and/or for working with sheet metal.

Butt Joint

A Butt Joint occurs when two metal objects are positioned directly adjacent to one another (edge-to-edge) in the same plane and subsequently welded along the lengthwise seam.

The Butt Joint is among one of the most common forms of weld joints and is typically used whenever a clean and linear weld joint configuration is required.

Examples of applications:

• Pipe welding

• Structural steel connections

• Plate fabrication

• Frames & supports

Lap joint

A lap joint is produced when one piece of metal overlies another piece of metal and the weld joint is located at the intersecting edges of these overlapping areas.

This joint is most commonly used for thinner metals and sheet metal-type fabrication.

Examples of applications:

• Sheet metal fabrication

• Automotive panels

• Light duty fabrication

• Repair work

Tee joint

When two metal components intersect at nearly a 90 degree angle (forming a tee shape); a tee joint has been created. Fillet welds are typically used in conjunction with tee joints.

Examples of applications:

• Brackets

• Structural support members

• Machinery frame components

• Reinforcement members

Corner joint

A corner joint exists when two metal components intersect at a corner (usually creating an L-shape).

This type of joint is commonly found in box-shaped assemblies and fabricated components.

Examples of applications:

• Enclosed Boxes

• Framed structures

• Tanks

• Cabinets

Welding vs Fabrication

Although welding and fabrication have many similarities, there is a difference in the terminology between the two.

Welding specifically refers to a process that joins metals by applying either heat, pressure, or a combination of the two. The goal of welding is to create a strong bond between two or more individual parts of material.

Fabrication is the general process that involves taking raw metal and developing it into a completed product or structure. 

A few examples of typical steps involved in fabricating include measuring, cutting, drilling, bending, fitting, welding, finishing, assembly, etc. In essence, welding is generally a smaller part of the entire fabrication process. 

Conclusion

Welding has become essential for modern construction, manufacturing and industrial workers due to its ability to create strong, permanent connections that enable the creation of everything from structural steel and heavy equipment to trailers and consumer goods. 

Understanding the basic principles of welding (such as the different methods of welding), various weld joints, and what makes welding distinct from fabrication will provide a greater understanding about how metal-based projects are created and/or repaired. 

Regardless of the type of job or project, welding is an invaluable trade that continues to make significant contributions to multiple industries.

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Here at CKF Industrial Contractors, LLC we offer reliable welding services in Hawaii for structural steel repair, fabrication, industrial repairs and other industrial welding needs. Call us now to review your project and see how we can assist you.

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