What Are the 8 Materials Commonly Used in Sheet Metal Fabrication?
Material choice sets cost, strength, weight, and finish. We wrote this to cut guesswork and prevent redesigns with clear, real-world guidance.
The eight most-used sheet metals are mild steel (CRS), stainless steel (304/316), aluminum (5052/6061), copper, brass, galvanized steel (HDG), titanium (Grade 2), and electro-zinc-coated steel (EG). We’ll map when to use each and the trade-offs.
Get material-specific tips for bends, welds, and coatings—plus DFM notes, finish limits, and comparison tables based on Okdor’s real prototyping experience.
Table of Contents
When should I use mild steel for sheet metal parts?
Mild steel is the most cost-effective choice when you need reliable strength, easy fabrication, and standard tolerances without premium finishes. It’s well suited for everyday parts such as brackets, racks, and audio housings, especially in indoor environments where corrosion is less of a concern.
With tensile strength in the 250–400 MPa range and typical tolerances of ±0.1 mm under ISO 2768-m, mild steel provides dependable performance without driving up machining time or inspection cost. Compared with stainless steel, it often comes in at 30–40% lower cost, and unlike aluminum, it resists denting under heavy loads.
In practice, mild steel delivers the best value in industrial enclosures, support frames, and other components where powder coating or paint can provide enough protection. Where developers sometimes run into trouble is by over-specifying surface finishes (for example, Ra ≤ 0.8 µm) or unnecessarily tight tolerances. Those requirements eliminate its price advantage because they demand polishing and extra inspection that mild steel doesn’t naturally lend itself to.
Design Takeaway: Mild steel is your go-to when the priority is low cost with adequate strength. Just plan a protective coating if moisture is present, and reserve tight tolerances only for critical features — that balance keeps your design manufacturable and cost-efficient.
What trade-offs will stainless steel bring to my design?
Stainless steel offers excellent corrosion resistance and a premium look, but it comes at a higher cost and can be harder to machine. For many product developers, it’s the logical step up from mild steel when strength and surface durability are key requirements.
Grades such as 304 and 316 stainless are common in sheet metal work. They provide tensile strengths above 500 MPa and maintain dimensional stability in harsh environments. However, machining stainless generates more tool wear, which translates into higher part cost and longer lead times compared to mild steel. The added weight of stainless is also worth considering if your project values lightness.
From our experience, stainless pays off in medical housings, food-contact equipment, and outdoor enclosures where untreated mild steel would fail quickly. The trade-off is budget: stainless parts typically run 30–60% more expensive, and design concessions (like larger bend radii) may be needed to avoid cracking.
Design Takeaway: Use stainless when corrosion resistance or hygiene compliance is critical. Accept that it will increase cost, and design with manufacturability in mind by avoiding overly tight bends or unnecessary cosmetic requirements.
Will stainless steel add cost or limit my finish choices?
Yes — stainless is more expensive to machine, and while it has fewer finish options than mild steel, it offers a naturally clean surface that often needs no coating. This balance is why many developers choose stainless for visible, consumer-facing products.
Unlike mild steel, stainless doesn’t require painting or powder coating for protection. Standard surface finishes of Ra 0.8–1.6 µm are achievable with proper tooling, and brushed or polished looks can be added for aesthetics. The challenge is cost: machining stainless can be 40–60% higher, mainly due to tool wear and slower cutting speeds.
In practice, stainless is often chosen when the “finish is built in.” For example, brushed stainless faceplates in audio equipment or polished surfaces in medical devices look professional without additional processing. Where we see mistakes is when developers still specify coatings or unnecessary polishing steps — adding cost without functional gain.
Design Takeaway: If you need durability and a professional finish without secondary coatings, stainless is worth the investment. Keep cosmetic requirements realistic and leverage its natural corrosion resistance to avoid extra finishing costs.
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Where does stainless steel make sense in product design?
Stainless steel is the right choice when your part must resist corrosion, meet hygiene standards, or deliver a premium, uncoated finish. It excels in environments where mild steel would fail quickly, such as outdoor exposure, frequent cleaning, or contact with food and medical equipment.
Grades like 304 and 316 provide tensile strengths above 500 MPa, giving solid structural performance. Their key value is durability: while coated mild steel can last indoors, stainless avoids the risk of coating damage or rust bleed-through in service. The trade-off is weight (about 3× heavier than aluminum) and machining cost, which typically runs 30–60% higher than mild steel.
We’ve seen stainless add lasting value in medical housings (ISO 13485 contexts), commercial kitchens, outdoor enclosures, and consumer-facing faceplates where aesthetics and durability both matter. In contrast, if weight reduction is a priority, aluminum often provides better value.
Design Takeaway: Stainless is worth the cost when long-term corrosion resistance, hygiene, or premium appearance are critical. Accept higher cost and weight, and design bends with larger radii to reduce cracking risk. If weight is more important than durability, aluminum may be the smarter option.
When is aluminum the best option for my project?
Aluminum is the best fit when your design needs light weight, good corrosion resistance, and flexible finishing options. At roughly 2.7 g/cm³, it’s only one-third the density of stainless steel, making it ideal for portable or weight-sensitive products.
Common alloys like 5052 and 6061 offer tensile strengths of 200–300 MPa. While not as strong as stainless, they’re sufficient for most sheet metal enclosures, brackets, and panels. Aluminum is also easier to machine, so despite raw material being 20–40% more expensive than mild steel, finished part costs can rival stainless because machining times are shorter and tool wear is lower.
From our projects, aluminum performs especially well in aerospace brackets, electronics housings, audio chassis, and outdoor panels where strength-to-weight ratio matters. It also anodizes well, offering durable and attractive finishes without the weight penalty of stainless.
That said, aluminum has limits: it dents more easily, has lower fatigue resistance, and loses strength at high temperatures. These drawbacks don’t disqualify it — but they mean design intent must be clear.
Design Takeaway: Choose aluminum when lightweight strength and corrosion resistance are your main goals. It’s cost-effective for weight-sensitive applications, especially with anodized or powder-coated finishes. But be aware of its limitations in fatigue and wear — issues we’ll explore in detail next.
What design limits should I watch for with aluminum?
Aluminum’s drawbacks are lower strength, denting under load, fatigue cracking, and loss of strength at elevated temperatures. These aren’t dealbreakers, but they shape where aluminum works best — and where it doesn’t.
Typical grades like 5052 and 6061 offer tensile strengths of 200–300 MPa, compared with >500 MPa for stainless. In exchange, you save nearly 65% in weight (2.7 g/cm³ vs ~8 g/cm³). This makes aluminum excellent for housings, panels, and brackets that benefit from lighter handling but don’t see heavy cyclic stress.
Where problems arise is when designers treat aluminum like steel. We’ve seen thin housings dent in drop tests until wall thickness was increased by just 0.5 mm. Similarly, fatigue failures show up in brackets under vibration unless geometry is reinforced. Welding is possible, but joints can be weaker and require proper alloy selection.
Design Takeaway: Aluminum is best for lightweight enclosures and panels, but don’t expect it to carry the same structural loads as steel. Build in wall thickness, use anodizing for wear protection, and avoid pushing it into high-heat or high-stress environments.
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When should I consider copper or brass in sheet metal design?
Copper and brass make sense when conductivity, corrosion resistance, or aesthetics are essential — not when structural performance or cost efficiency is the main concern. They are specialty materials that solve problems steel and aluminum cannot.
Copper is unmatched for electrical and thermal conductivity, making it the right call for busbars, EMI shielding, or thermal plates. Brass brings better stiffness, attractive golden appearance, and good machinability, which works well in decorative trims, architectural panels, and premium audio components. Both, however, are heavy (~8.5 g/cm³) and costly — often 2–4× more than mild steel.
From experience, issues arise when copper or brass are specified in place of structural metals. Neither holds up as well under heavy loads or repeated impact. Copper in particular scratches easily, which can disappoint in consumer-facing products unless a protective finish is applied.
Design Takeaway: Consider copper for conductivity and brass for corrosion resistance or aesthetics. Avoid using either as low-cost structural substitutes. Their higher cost and weight are justified only when their unique properties directly enhance function or design value.
What trade-offs come with choosing copper or brass?
The main trade-offs with copper and brass are higher cost, added weight, and limited structural performance. While their conductivity, corrosion resistance, and appearance make them valuable in niche designs, they are rarely the most economical choice.
Both alloys are 2–4× more expensive than mild steel and nearly as heavy as stainless (~8.5 g/cm³). Copper is soft and prone to denting, while brass improves stiffness but still falls short of steel for load-bearing roles. They do machine cleanly and polish well, but copper can scratch during handling, and brass requires generous bend radii to avoid stress cracking.
From the way we see, these materials only justify their premium when their unique properties — conductivity for copper, decorative finish for brass — directly enhance function or brand value. In most other applications, steel or aluminum provide better performance for lower cost.
Design Takeaway: Reserve copper and brass for parts where their distinct properties matter, such as electrical conductors or decorative housings. Otherwise, their higher price and weight quickly outweigh the benefits.
When does galvanized steel fit best in a design?
Galvanized steel is the best fit when you need affordable corrosion resistance without moving to stainless. It provides the strength of mild steel with a zinc coating that protects against rust in outdoor or humid conditions.
Hot-dip galvanized steel creates a thick, durable coating suited for structural parts and industrial use, while electro-galvanized steel offers a thinner, smoother layer that works better in consumer products. In both cases, you retain the ~250 MPa tensile strength of mild steel while extending service life considerably.
We often see galvanized steel succeed in HVAC ducting, outdoor brackets, utility enclosures, and automotive panels where cost control is important but corrosion would otherwise shorten service life. The trade-off is in finish flexibility — coatings limit some paint or plating options, and the surface rarely achieves the clean look of stainless or anodized aluminum.
Design Takeaway: Choose galvanized steel when your priority is low-cost durability for outdoor or industrial environments. It won’t match stainless for aesthetics or lifespan in harsh chemicals, but it offers strong protection at a fraction of the cost.
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Is titanium realistic for my sheet metal project, or too costly?
Titanium offers outstanding strength-to-weight and corrosion resistance, but its high cost and forming challenges make it realistic only in specialized projects. For most designs, stainless or aluminum deliver similar performance at far lower price.
Commercially pure Grade 2 titanium provides tensile strength of ~350 MPa at a density of 4.5 g/cm³, nearly half the weight of steel for comparable strength. High-performance alloys like Grade 5 Ti-6Al-4V exceed 900 MPa, but they require slower machining and more expensive tooling. Raw titanium sheets are typically 5–10× the cost of mild steel, and finished parts often price out at 3–5× the cost of aluminum equivalents once machining and finishing are factored in.
The other hidden cost is manufacturability. Titanium resists forming — tight-radius bends may crack or require specialized press tooling, and springback is higher than steel or aluminum. These factors increase setup time and reduce design flexibility.
Titanium is justified in aerospace brackets, defense housings, and high-end medical enclosures where every gram matters or where stainless would be too heavy. For most industrial parts, however, stainless or aluminum deliver 80–90% of the function at a fraction of the cost.
Design Takeaway: Use titanium only when exceptional strength-to-weight or corrosion resistance is mission-critical. Expect higher part cost and forming restrictions. For general sheet metal work, stainless or aluminum are usually the smarter, more economical choices.
When is zinc-coated sheet metal the right choice?
Zinc-coated steel is a smart choice when you need corrosion resistance, paint-friendly surfaces, and cost control for indoor or light-duty outdoor products. It fills the gap between bare mild steel and heavier hot-dip galvanized.
Electro-zinc coatings form a thin, uniform layer that provides a smooth surface for painting or plating while adding moderate corrosion resistance. This makes it well-suited for appliances, automotive panels, and indoor enclosures where appearance and finish quality matter. Mechanically, it retains the ~250 MPa tensile strength of mild steel, but its service life depends heavily on environment. Indoors, zinc coatings can last 10–20 years; outdoors, they wear faster than galvanized coatings and are not recommended for marine or chemical exposure.
In practice, zinc-coated steel usually costs slightly more than uncoated mild steel but less than galvanized, making it a budget-friendly way to extend lifespan without committing to stainless. Compared with painted mild steel, it offers better adhesion and fewer rust risks if the surface is scratched.
Design Takeaway: Choose zinc-coated steel when you need low-cost durability with a smooth, paintable surface. It’s excellent for consumer-facing housings and indoor products, but for long-term outdoor or harsh chemical environments, galvanized or stainless are safer choices.
How do I balance cost, strength, and durability across materials?
The key is to match material choice to your part’s functional priorities, not to chase the strongest or cheapest option in isolation. Every metal brings trade-offs, and the best fit depends on whether cost, weight, corrosion resistance, or aesthetics drives your design.
For cost-sensitive industrial parts, mild steel or galvanized steel usually offer the lowest total expense. If durability or hygiene is critical, stainless steel pays off despite higher machining costs. For weight reduction, aluminum balances moderate strength with excellent corrosion resistance, while titanium justifies itself only in aerospace or medical projects where weight and performance outweigh budget. Copper and brass are niche choices for conductivity or appearance, and zinc-coated steel provides a middle ground for consumer-facing parts where paintability and light-duty corrosion resistance matter.
A practical way to approach this is to ask: What will failure cost me? If surface rust would damage your brand, stainless is safer. If weight directly affects usability, aluminum or titanium may save downstream cost. If appearance sells the product, brass or zinc-coated steel provide visual quality without overengineering.
| Material | Relative Cost* | Strength (Tensile MPa) | Corrosion Resistance | Weight (Density g/cm³) | Finish Flexibility | Best-Fit Use Cases |
|---|---|---|---|---|---|---|
| Mild Steel (CRS) | 1.0 (baseline) | ~250 MPa | Poor (needs coating) | 7.8 | Excellent (paint, powder, plating) | Low-cost indoor brackets, frames, enclosures |
| Stainless Steel (304/316) | 1.4–1.6× mild steel | 500–600 MPa | Excellent (uncoated) | 7.9–8.0 | Limited (brushed, polished, passivated) | Medical housings, food equipment, outdoor enclosures |
| Aluminum (5052/6061) | 1.2–1.4× mild steel | 200–300 MPa | Good (natural oxide) | 2.7 | Very good (anodize, paint, powder coat) | Aerospace brackets, electronics housings, panels |
| Copper | 2–4× mild steel | ~200 MPa | Good | 8.9 | Polishes, coats, but scratches easily | Busbars, EMI shielding, heat sinks |
| Brass | 2–4× mild steel | 350–550 MPa | Good | 8.5 | Polishes to decorative finish | Decorative panels, trims, premium audio housings |
| Galvanized Steel (HDG) | 1.1–1.2× mild steel | ~250 MPa | Good (zinc layer) | 7.8 | Limited (paint adhesion issues) | Outdoor brackets, HVAC ducting, utility enclosures |
| Titanium (Grade 2 / 5) | 5–10× mild steel | 350 MPa (Grade 2) / >900 MPa (Grade 5) | Excellent (uncoated) | 4.5 | Limited (costly to finish, form issues) | Aerospace, defense, high-end medical enclosures |
| Zinc-Coated Steel (EG) | 1.1–1.3× mild steel | ~250 MPa | Moderate (indoor use) | 7.8 | Smooth, paintable, plateable | Consumer appliances, automotive panels, indoor enclosures |
Design Takeaway: Balance cost, strength, and durability by ranking your priorities early — budget, weight, corrosion, or appearance. Then select the material that meets the must-haves without over-specifying. Our role as a machining partner is to help you review these trade-offs up front, so you avoid costly redesigns later.
Conclusion
Selecting the right sheet metal material means balancing cost, strength, and durability. Each option has trade-offs, but the right choice prevents redesigns and reduces risk. At Okdor, we help developers optimize material decisions and manufacturability. Contact us to explore manufacturing solutions tailored to your product requirements.
Frequently asked questions
Always confirm whether your drawings specify “before coating” or “after coating” dimensions. Even thin coatings (10–25 µm) can affect snap fits, sliding panels, or threaded holes.
Ask whether your product is load-bearing or portability-driven. For strength, stainless or galvanized steel is safer. For portability or performance, aluminum is usually sufficient, and titanium is the premium option if budgets allow.
Medical and food products typically require stainless 304/316. Aerospace projects often call for aluminum or titanium per AMS/ASTM specs. Choosing early avoids redesign when compliance checks begin.
Over-specifying. Developers often default to stainless or titanium for “safety,” but this inflates cost. Matching the environment and loads to the right grade (e.g., galvanized for outdoor industrial use, aluminum for portable products) keeps designs both reliable and affordable.
Often, galvanized or zinc-coated steel gives adequate corrosion resistance for indoor or semi-outdoor products at lower cost. Stainless is only worth it if hygiene, premium aesthetics, or harsh environments demand it.
Stainless (brushed/polished) and brass (decorative golden tone) look premium as-is. Aluminum with anodizing also delivers high aesthetics. Galvanized and zinc-coated steels usually require paint to look consumer-ready.
