Quando si lavora con lamiere, sia per parti automobilistiche, costruzione, or consumer goods—understandingsheet metal thickness standards e ilgauge system is non-negotiable. Il sistema di misurazione utilizza un controintuitivo, scala non lineare (numeri più piccoli = metallo più spesso) che può confondere anche gli ingegneri esperti. Questa guida spiega come funziona il sistema di misurazione, fornisce tabelle di confronto dettagliate per 7 metalli comuni (acciaio, alluminio, rame, e altro ancora), shares real-world application examples, and answers critical questions to help you choose the right thickness for your project.
Primo: What Is the Sheet Metal Gauge System?
Unlike the metric system (which measures thickness directly in millimeters), the sheet metal gauge system is a historical standard based onweight per square foot of metal. This means:
- IL smaller the gauge number, IL thicker the metal (per esempio., 3 gauge steel = 6.07mm thick; 38 gauge steel = 0.15mm thick).
- Gauge standards vary by metal type (per esempio., 10 gauge steel is thicker than 10 gauge aluminum)—density differences cause this variation.
Key Thickness Limits for “Sheet Metal”
By industry standard, metal is classified as “sheet metal” only if its thickness falls within a specific range:
- Lower limit: 0.5mm (thinner than this is considered foil, not sheet metal).
- Upper limit: 6mm (thicker than this is classified as “plate metal” and follows different standards).
Nota: Regional variations exist—some countries consider 8mm the upper limit for sheet metal. Always confirm with your supplier if working on international projects.
Sheet Metal Gauge Comparison Tables (By Metal Type)
Below are detailed gauge-to-thickness conversion tables for the 7 most commonly used metals in sheet metal processing. All measurements include both inches and millimeters for global compatibility.
1. Standard Steel Gauge Table
Standard steel (acciaio dolce) viene utilizzato per le parti strutturali, parentesi, and machinery components. Its gauge scale is the most widely referenced in manufacturing.
| Gauge | Spessore (In) | Spessore (mm) | Best Use Case |
|---|---|---|---|
| 3 | 0.239 | 6.073 | Heavy structural beams, industrial machinery frames |
| 4 | 0.224 | 5.695 | Large storage tanks, heavy-duty brackets |
| 5 | 0.209 | 5.314 | Truck bed floors, construction supports |
| 8 | 0.164 | 4.176 | Metal doors, safety barriers |
| 10 | 0.135 | 3.416 | Load-bearing brackets, parti di telai automobilistici |
| 12 | 0.105 | 2.657 | Condutture HVAC, metal shelving |
| 16 | 0.060 | 1.519 | Involucri elettrici, light-duty brackets |
| 20 | 0.036 | 0.912 | Thin metal panels, rifinitura decorativa |
| 30 | 0.012 | 0.305 | Precision electronics components, thin covers |
| 38 | 0.006 | 0.152 | Ultra-thin parts (rarely used for structural needs) |
2. Galvanized Steel Gauge Table
Galvanized steel has a zinc coating for corrosion resistance, making it ideal for outdoor or wet environments. Its gauge thickness includes the zinc layer (adds ~0.1mm to base steel thickness).
| Gauge | Spessore (In) | Spessore (mm) | Best Use Case |
|---|---|---|---|
| 8 | 0.168 | 4.270 | Outdoor fences, garden sheds |
| 10 | 0.138 | 3.510 | Pannelli di copertura, gutter systems |
| 12 | 0.108 | 2.753 | Outdoor furniture frames, mailboxes |
| 16 | 0.064 | 1.613 | Ventilation grilles, outdoor light fixtures |
| 20 | 0.040 | 1.006 | Thin roofing flashing, decorative outdoor trim |
3. Stainless Steel Gauge Table
Acciaio inossidabile (304/316 gradi) is corrosion-resistant and used for medical devices, attrezzature per la lavorazione degli alimenti, and marine parts. It has a wider gauge range than standard steel.
| Gauge | Spessore (In) | Spessore (mm) | Best Use Case |
|---|---|---|---|
| 000 | 0.375 | 9.525 | Marine hull components, heavy-duty food processing tanks |
| 3 | 0.250 | 6.350 | Industrial kitchen equipment, large chemical containers |
| 8 | 0.172 | 4.366 | Stainless steel sinks, countertop supports |
| 12 | 0.109 | 2.779 | Custodie per dispositivi medici, food conveyor belts |
| 16 | 0.063 | 1.588 | Cutlery, small kitchen appliances |
| 20 | 0.038 | 0.953 | Thin stainless steel panels, involucri elettronici |
| 30 | 0.013 | 0.318 | Precision medical instruments, small sensor housings |
4. Carbon Steel Gauge Table
Carbon steel (high-carbon) is stronger than standard steel but less corrosion-resistant. It’s used for tools, molle, and high-strength parts.
| Gauge | Spessore (In) | Spessore (mm) | Best Use Case |
|---|---|---|---|
| 3 | 0.239 | 6.07 | Heavy-duty tool bases, industrial springs |
| 8 | 0.164 | 4.18 | Metal cutting tools, machinery gears |
| 10 | 0.134 | 3.42 | Parti di sospensioni automobilistiche, high-strength brackets |
| 16 | 0.060 | 1.52 | Small tool components, thin springs |
5. Aluminum Sheet Gauge Table
Aluminum is lightweight (1/3 il peso dell'acciaio) e resistente alla corrosione, making it ideal for aerospace, automobilistico, e beni di consumo. Its gauge scale is thinner than steel for the same number.
| Gauge | Spessore (In) | Spessore (mm) | Best Use Case |
|---|---|---|---|
| 6 | 0.162 | 4.115 | Aircraft structural parts, heavy aluminum frames |
| 10 | 0.102 | 2.588 | Pannelli della carrozzeria automobilistica, aluminum ladders |
| 16 | 0.051 | 1.290 | Involucri per laptop, lattine per bevande (thinner grades) |
| 20 | 0.032 | 0.813 | Cornici per smartphone, thin aluminum sheets for signage |
| 30 | 0.010 | 0.254 | Ultra-thin aluminum foil (for packaging, not structural use) |
6. Copper Sheet Gauge Table
Copper is highly conductive and malleable, used for electrical wiring, idraulico, and decorative applications. Its gauge scale is thicker than aluminum but thinner than steel for the same number.
| Gauge | Spessore (In) | Spessore (mm) | Best Use Case |
|---|---|---|---|
| 7 | 0.180 | 4.572 | Heavy copper pipes, industrial electrical busbars |
| 10 | 0.134 | 3.404 | Medium-duty plumbing pipes, decorative copper panels |
| 16 | 0.065 | 1.651 | Electrical wiring insulation, thin copper sheets for crafts |
| 24 | 0.022 | 0.559 | Precision electrical components, rifinitura decorativa |
7. Brass Sheet Gauge Table
Ottone (copper-zinc alloy) is corrosion-resistant and has an attractive gold-like finish. It’s used for decorative parts, strumenti musicali, and plumbing fittings.
| Gauge | Spessore (In) | Spessore (mm) | Best Use Case |
|---|---|---|---|
| 7 | 0.144 | 3.665 | Musical instrument bells, heavy brass fixtures |
| 10 | 0.102 | 2.588 | Decorative wall panels, brass hardware |
| 16 | 0.051 | 1.291 | Small brass fittings, componenti di gioielleria |
| 24 | 0.020 | 0.511 | Thin brass sheets for engraving, rifinitura decorativa |
How to Choose the Right Sheet Metal Thickness (Passo dopo passo)
Selecting the correct thickness isn’t just about gauge numbers—it depends on your project’s load, ambiente, and manufacturing process. Segui questi 4 passi:
Fare un passo 1: Define Load Requirements
- Heavy load (per esempio., travi strutturali, truck beds): Choose 3–10 gauge (4–6mm thick) steel or aluminum.
- Medium load (per esempio., scaffali, parentesi): Choose 12–16 gauge (1.5–2.7mm thick).
- Light load (per esempio., rifinitura decorativa, involucri elettronici): Choose 18–24 gauge (0.7–1.2mm thick).
Esempio: A construction company needed brackets for a 500kg load. They chose 8 gauge steel (4.18mm di spessore)—12 gauge (2.66mm) would have bent under the weight.
Fare un passo 2: Consider Environmental Conditions
- Outdoor/wet environments: Use galvanized steel (10–16 gauge) o acciaio inossidabile (12–20 gauge) per la resistenza alla corrosione.
- Indoor/dry environments: Standard steel (12–20 gauge) or aluminum (16–24 gauge) works—cheaper than corrosion-resistant metals.
Caso di studio: A garden furniture maker switched from standard steel (16 misura) to galvanized steel (16 misura) for outdoor chairs. The galvanized chairs lasted 5 anni (contro. 2 years for standard steel) without rusting.
Fare un passo 3: Match Thickness to Manufacturing Process
- Lavorazione CNC: Thicker metal (8–12 gauge) is easier to machine—thin metal (20+ misura) bends during cutting.
- Bending/Forming: Medium thickness (16–20 gauge) is ideal—too thick (8–12 gauge) cracks when bent; too thin (24+ misura) warps.
- Saldatura: Thicker metal (10–16 gauge) creates stronger welds—thin metal (20+ misura) burns through during welding.
Tip: For parts that need both bending and welding (per esempio., telai metallici), 16 gauge steel is the sweet spot.
Fare un passo 4: Use the Gauge Comparison Table to Verify
Once you’ve narrowed down your needs, cross-check with the appropriate gauge table. Per esempio:
- Hai bisogno di un peso leggero, corrosion-resistant part for a laptop casing? Utilizzo 20 gauge aluminum (0.813mm di spessore) from the aluminum gauge table.
- Need a heavy-duty structural part for a truck? Utilizzo 8 gauge standard steel (4.176mm di spessore) from the standard steel table.
Common Myths About Sheet Metal Gauge (Debunked)
Myths about the gauge system lead to costly mistakes. Ecco 3 common misconceptions:
Myth 1: “All metals use the same gauge scale.”
Fact: Gauge varies by metal density. UN 10 gauge steel sheet (3.416mm) is thicker than a 10 gauge aluminum sheet (2.588mm)—aluminum is less dense, so the same gauge number corresponds to a thinner thickness. Always use the metal-specific gauge table.
Myth 2: “Thicker metal is always more corrosion-resistant.”
Fact: Thickness only affects howlungo metal takes to corrode—not if it corrodes. A thin stainless steel sheet (20 misura, 0.953mm) is more corrosion-resistant than a thick standard steel sheet (8 misura, 4.176mm) because stainless steel has chromium, which prevents rust.
Myth 3: “Gauge is more accurate than metric thickness.”
Fact: Metric thickness (mm) is a direct measurement—gauge is a historical weight-based standard with slight variations between suppliers. Per parti critiche (per esempio., dispositivi medici), specify thickness in millimetersE gauge to avoid confusion.
Yigu Technology’s Perspective on Sheet Metal Thickness & Gauge
Alla tecnologia Yigu, we help clients navigate the gauge system to avoid costly errors. For structural parts, we recommend referencing the standard steel or stainless steel gauge tables and prioritizing thickness over gauge number. For lightweight or corrosion-sensitive projects, we guide clients to aluminum or galvanized steel, using their specific gauge tables to find the right balance of strength and weight. We also provide sample pieces of different gauges, so clients can see and test thickness before full production. For us, the gauge system is a tool—but the goal is always to match thickness to your project’s unique needs, not just follow a number.
FAQ About Sheet Metal Thickness Standard & Gauge
1. Can I use a steel gauge table for aluminum parts?
No—aluminum has a different gauge scale than steel. UN 10 gauge steel sheet (3.416mm) is thicker than a 10 gauge aluminum sheet (2.588mm). Using the wrong table will result in a part that’s too thin (if you use steel gauge for aluminum) or too thick (if you use aluminum gauge for steel).
2. What’s the difference between “sheet metal” and “plate metal”?
Sheet metal has a thickness of 0.5–6mm (misura 38 to gauge 3). Plate metal is thicker than 6mm (no standard gauge) and is used for heavy-duty applications like bridges or ship hulls. Always confirm if your project requires sheet or plate metal—using plate metal when sheet metal works wastes money.
3. How do I convert gauge to millimeters if I don’t have a table?
Per la maggior parte dei metalli, you can use a general rule (but always verify with a metal-specific table):
- Acciaio: Gauge 10 = ~3.4mm, misura 16 = ~1.5mm, misura 20 = ~0.9mm.
- Alluminio: Gauge 10 = ~2.6mm, misura 16 = ~1.3mm, misura 20 = ~0.8mm.
Per parti critiche, never rely on estimates—use the official gauge tables provided in this guide.