When choosing a material for your metal fabrication project, formability, weldability, corrosion resistance, strength, weight, finishability, and cost should all be considered. Finding the right metal and its properties will determine your project’s aesthetics and functionality, as well as its wearability and cost. Common questions to ask during the design, development, and specification phases of your metal fabrication project include: What is the intended use of the final product? Would I like any kind of finish on the metal? Are there any finite details that require a certain kind of flexibility in the metal? The following topics are all things you should contemplate when evaluating steel, stainless steel, aluminum, copper, and brass for your next project. 

Metal Fabrication Strength and Corrosion Resistance Properties

When specifying the metal for your next project, both strength and anticipated loads during use should be identified. Typical strength specifications include yield strength and tensile strength. If your product will be exposed to outdoor conditions when completed or will come in contact with any harsh chemicals, the metal’s resistance to corrosion is another factor to evaluate. 

• Yield strength: Yield strength is used to determine the maximum load a metal can take before it deforms or bends permanently. For applications like springs or car frames, choose a material that has a high yield strength to ensure your part can maintain its shape under pressure.
• Tensile strength: Tensile strength measures the force or maximum amount of strength required to break, fracture, or pull a material apart. If your component bears a large load, a high-tensile-strength metal is crucial. If your project requires a degree of flexibility, a metal that balances strength and weight might be desirable.
• Corrosion resistance: If your final piece will be exposed to environmental factors such as moisture and chemicals, you should consider a highly corrosion-resistant metal such as stainless steel. Aluminum is moderately corrosion-resistant. Copper and brass would require more ongoing maintenance.

Metal Fabrication Processes and Workability

Metal fabrication utilizes various techniques such as mechanical and thermal cutting, forming and joining to transform metals into the desired shapes and structures. A metal’s workability, a crucial parameter, evaluates a material’s ability to be cut, bent, shaped, formed, welded, and more.

• Machinability: How easily does the material need to be cut, drilled and shaped? Does your final component require intricate designs? Aluminum provides good machinability at a lighter weight. Brass also machines well, while copper can pose some difficulties because of its high ductility and malleability.
• Weldability: Joining metal pieces is a requirement for many projects. Can the material be easily welded to itself and/or to other metals? Does it require a lot of preparation or specialized tools and techniques to be welded? Steels offer good weldability with various techniques. Stainless steel, specifically, requires specialized welding techniques. Aluminum is weldable but more sensitive. Copper and brass weld well but produce hazardous fumes that require special protection.
• Formability: Bending, shaping, and drawing metals into the desired shape should be considered. Does the component need to withstand ongoing forces in the final application, or does it simply need to be bent into shape and remain in the same state? Highly formable metals like aluminum and brass are ideal for intricate bends and curves, however steel is a very strong material that requires greater forces and applied heat to change shape.

Metal Fabrication Materials Cost and Availability

The cost and availability of metal fabrication materials can affect the cost and turnaround time of a project. Supply and demand, as well as country of origin and shipping costs, could all factor into the final budget of a project.

• Material Cost: Prices vary depending on supply, demand, properties, and processing. Common steels are relatively inexpensive, while specialty alloys can be more expensive. Aluminum is typically mid-range in price; copper and brass are in the higher cost range.
• Material availability: Steel and aluminum are often easier to source, while more specialized metals might require longer lead times or higher costs. 

Aesthetics and Finish

While it is not necessary to put a finish on the metal, depending on your project and what the overall goal for its use is, you might choose to add one. For example, if your piece is meant to be kept outside, you might choose a finish that will protect the metal from wearing in the unpredictable weather. Moreover, a finish will change the outside appearance of the metal, and can simply be chosen for aesthetic reasons. 

• Natural Finish: Copper and brass, often chosen for their warm tones and patina, provide a certain beauty in aesthetic applications. Stainless steel has a sleek, modern appearance. Aluminum can be anodized to achieve various colors. Steel’s finish depends on its material composition and type of treatment.
• Paintability: Does your final product need to be painted or does a finish need to be applied? Steel and aluminum provide a good base for painting, while copper and brass require special primers. Stainless steel can be painted, but surface preparation and the correct material must be chosen when considering the application.

Beyond the Basics

Each metal has unique properties and characteristics. It is important to consult fabrication experts to ensure the correct metal is chosen for your project’s specifications. Following is a summary of common materials and their qualities.

• Steel is versatile and affordable, and often used in construction and machinery. Its diverse alloy variations provide options for strength, formability and corrosion resistance properties. However, steel can also rust easily and might require more frequent maintenance than stainless steel.
• Stainless steel has superior corrosion resistance and durability. It is ideal for hygienic/medical applications and food processing. It is also highly weather-resistant, making it a good choice for architectural details and outdoor components. However, it does have particular welding requirements and can often cost more to procure.
• Aluminum can be lightweight and strong, making it a common choice for aircraft, transportation and consumer good applications. It is also easily machinable and corrosion-resistant. As a consequence to this, though, aluminum has a harder time resisting deformation.
• Copper is aesthetically pleasing, making it a good choice for decorative elements. It is also highly conductive and ideal for use in electrical wiring and heat exchangers. However, it is susceptible to corrosion and can often carry a higher cost.
• Brass is workable and has a nice golden finish. It is used in plumbing, musical instruments and decorative accents. Brass can tarnish, so it does require maintenance to keep the shiny finish.

Choosing the Ideal Metal

At the end of the day, choosing the ideal metal for your application will include a variety of factors to mull over. Understanding the qualities of each material and comparing them to your project’s specifications and budget, will help you match the material to your end goal.