Why Aluminium Plates are Widely Used
Aluminium plates are a top choice for industrial projects. This is because it is very strong, light and resistant to corrosion. Aluminum is everywhere, from tall buildings and swift aircraft to deep-sea vessels. Its superior strength-to-weight ratio often makes it better than steel.
However, choosing the correct material thickness is vital for project success and safety. Selecting the wrong thickness can lead to early structural failure or unnecessary high costs. A plate that is too thin will break under stress. A plate that is too thick wastes material and makes the final product too heavy.
This blog will guide you through the process. We will look at what thickness means for aluminium. We will explore key factors like load, application environment, and material grade. Finally, we will offer a clear decision framework and suggested thicknesses for major industries. This information will help you select the ideal aluminium plate thickness for your industrial needs.
Understanding Aluminium Plate Thickness
Aluminium plate thickness is a key feature that defines its use. Aluminium plates usually start at a thickness of 6mm and can go up to 200mm. For thinner material, the terms change.
- An aluminium sheet is typically less than 6mm thick.
- An aluminium plate is 6mm thick or greater.
- An aluminium coil is simply long, rolled-up sheet metal.
The thickness has a direct impact on the plate’s properties. As thickness increases, so do:
- Weight: A thicker material makes the final product heavier. A 10mm plate, for instance, weighs more than three times as much as a 3mm plate.
- Strength: A thicker plate can take a lot more pressure and tension.
- Rigidity: Thicker plates are less likely to bend and deflect under stress, which makes the structure more rigid.
Knowing these differences is the first step toward the right choice.
Factors That Influence the Right Plate Thickness
Determining the right plate thickness involves balancing performance with cost. You must consider several real-world requirements. These factors will guide you immediately to the proper thickness range.
1. Load & Structural Strength Requirements
Static vs. Dynamic Loads: Static loads are steady weights, like a fixed wall panel. Dynamic loads involve movement or sudden impact like a bridge deck or a car chassis. Dynamic loads always require thicker plates for better fatigue resistance.
High-Load Areas: A thicker plate is needed for any part that get repeated forces. This increases the material’s tensile strength. In these critical areas, engineers often make the plate thicker to give it an extra safety margin.
Tensile Strength: This is the amount of force needed to pull the plate apart. Thickness directly improves the overall tensile strength of the part.
2. Application Environment
Marine: Saltwater environments need thicker plates (often 5083 grade) because of high corrosion risk. Extra thickness ensures a longer lifespan even as the surface corrodes over time.
Aerospace: Weight is a major concern. Thinner plates are preferred, but they must use high-strength grades like 7075. Every saved kilogram means lower fuel costs.
Chemical Industry: Depending on the chemicals involved, you may need a specific corrosion-resistant grade. Thickness is often determined by the pressure the material must withstand.
3.Type of Aluminium Grade Used
Different grades have different strengths. A high-strength grade might allow you to use a slightly thinner plate.
6061: Excellent all-purpose grade. Paired with medium to thick plates for structural applications like building frames.
5083: It is best for marine and weldable structures. It is used in medium to thick plates for ship hulls and tanks.
7075: Extremely strong, reserved for aerospace and high-stress parts. It is usually used in thinner plates where strength-to-weight is vital.
1100/3003: Softer and best for general purpose, heat exchangers, and high corrosion resistance.
4. Fabrication Process
Bending: Thinner plates bend easily and require less force. Thicker plates (e.g., above 12mm) can be difficult or impossible to bend.
Machining: Thicker plates are better for machining. They offer more stability and less vibration when cutting complex parts.
Welding: Very thin plates (under 3mm) are hard to weld. Very thick plates (over 25mm) require special techniques. Suitability is often best in the medium range.
6.Temperature & Pressure Exposure
High Temperature: Excessive heat can weaken aluminum. Thicker plates are used to keep the structure stable and safe at higher temperatures.
Cryogenic Applications: Extremely cold temperatures require specific grades like 5083, which maintain strength without becoming brittle. Plate thickness must meet relevant pressure vessel design codes.
Durability & Lifespan Requirements
Projects needing a long life in harsh conditions, like heavy machinery or outdoor storage tanks, need thicker plates. This accounts for erosion, fatigue, and potential damage over decades.
Recommended Aluminium Plate Thickness for Key Industries
Selecting a specific thickness is crucial, as it directly impacts both the safety and the total efficiency of your project. The ideal range is always dictated by the real-world demands of the application.
Construction Industry
The construction sector uses aluminium plates where weight savings are needed without losing strength.
Structural Panels and Cladding: Common thicknesses are 6mm, 8mm and 10mm. These plates (often Grade 6061) offer a great balance. They are rigid enough for large panels, but still light compared to steel, making installation easier.
Load-Bearing Applications: For bridges, heavy-duty platforms, or major structural components, you will see plates in the 12mm to 20mm range. This added thickness is necessary to handle extreme static and dynamic loads and meet safety codes.
Aerospace
In aerospace, the rule is simple: high strength and minimal weight. This means using thinner plates made from ultra-strong grades.
Body Panels and Non-Critical Structure: Thicknesses of 2mm to 6mm are preferred. Grades like 7075 and 2024 are used because they are incredibly strong, allowing the material to be thin to save weight.
Critical Load Parts: Parts like wing structures, main bulkheads and engine mounts may need plates that are 8mm thick or more. Alloys like 7075 are ideal for parts that have to handle a lot of stress as they have a high strength-to-weight ratio, even at medium thickness.
Marine & Shipbuilding
Saltwater corrosion and structural integrity against waves are the main concerns here.
Hull and Deck Parts: The typical range is 4mm to 12mm, depending on the size of the vessel and the specific part. Thinner plates (4–6mm) may be used for internal bulkheads. Thicker plates (8–12mm) are common for the main hull and deck surfaces.
Grade Preference: The 5083 grades are chosen almost always. This is because they have high amounts of magnesium which given them superior resistance to saltwater corrosion. This ensures the vessel will last a long time.
Automotive
The automotive industry uses aluminium to lighten vehicles, which improves fuel economy and performance.
Body Parts and Exterior Panels: Very thin plates or thick sheets, often 2mm to 6mm, are used. This keeps the material light while providing necessary stiffness and crash absorption.
Chassis Reinforcements: Parts that absorb impact or support the engine often use plates from 8mm to 12mm thick. This thickness adds the required strength for critical safety areas.
Heavy Engineering & Machinery
This sector requires plates for tooling, jigs, machine beds, and massive structural frames where rigidity and precision are vital.
Machinery Components: Plates ranging from 16mm to 80mm are standard. This great thickness is needed to reduce vibration during machining, maintain stability under heavy industrial use, and allow for deep machining of complex parts. Grade 6061 is a common choice here.
Oil & Gas / Pressure Vessels
Safety and adherence to strict design codes (like ASME) are the most important factors.
Vessel Walls and Piping: Thicknesses from 10mm to 50mm are common. The exact size is determined by the pressure and temperature the vessel must contain. Thicker plates are required for higher pressure and larger diameters to prevent bursting or collapse, using grades like 5083 for low-temperature (cryogenic) applications.
Thickness vs Weight Chart (Simple Table)
Weight is a critical consideration for cost, handling, and final performance. This simple table shows how the weight of the plate quickly increases with thickness. (Note: These are estimated weights for pure aluminium, measured in kilograms per square meter, kg/m²).
| Plate Thickness | Estimated Weight (kg/m2) |
| 3mm | ≈8.1 kg/m2 |
| 6mm | ≈16.2 kg/m2 |
| 10mm | ≈27.0 kg/m2 |
| 20mm | ≈54.0 kg/m2 |
The relationship is nearly linear. If you double the thickness, the weight will almost double. This stark contrast shows why it’s important to avoid extra thickness to save money.Mistakes to Avoid When Selecting Plate Thickness
To make sure your project goes as planned and stays within budget, avoid common mistakes. It’s not always best to just pick the thickest option. The right choice is often a balance.
- Choosing based only on cost: Thin plates are cheaper to buy. But if they fail early, the cost of repair and project downtime will be far higher.
- Ignoring weight limitations: In transport or aerospace, extra weight directly increases operating costs. Don’t over-specify thickness if a thinner, high-grade material will work.
- Overlooking welding or bending requirements: Welding very thick plates is slow and costs a lot of money. To bend them, you also need high-force tools. Ensure your selected thickness works with your shop’s capabilities.
- Not checking industry standards: For safety reasons codes like ASME (pressure vessels) or ISO often require a minimum plate thickness. Not paying attention to these is a major legal risk.
- Wrong grade selection: It’s inefficient to choose a weak, cheap grade (like 1100) and compensate for it by increasing the thickness. Match a suitable grade (like 6061) with the correct thickness.
How to Make the Final Selection (Decision Framework)
Use a clear, step-by-step approach to narrow down your options quickly. This framework combines all the factors discussed above into an easy process.
- Identify Load Requirements: Determine the maximum stress and type of load (static or dynamic) the plate will carry. This sets the minimum required strength.
- Check Application Environment: Is the plate exposed to saltwater, high heat, or corrosive chemicals? This will help you select the correct aluminium grade.
- Consider Fabrication: How will the part be made? If it needs complex bends, you must choose a thinner, more flexible plate. If it requires heavy machining, you’ll need a thicker plate.
- Calculate Weight Limits: Determine the maximum allowable weight for the final product. This will set the maximum permissible thickness.
- Follow Industry Standards: Always check the relevant codes for your industry (e.g. construction, marine). This will set the minimum safe thickness.
Quick Decision Table
| Primary Goal | Plate Thickness Guide |
| Max Strength/Stiffness | Choose a Thick plate (12mm+) |
| Max Corrosion Resistance | Choose a high-grade plate (5083), then choose thickness based on load |
| Max Lightweight/Fuel Efficiency | Choose a Thin plate (2–6mm) with a high-strength grade (7075) |
| Easy Fabrication/Bending | Choose a Thin plate (under 8mm) |
Choosing the right thickness of aluminum plate is important as it affects the safety, cost, and length of your industrial project. It involves careful thought, not guesswork. You need to find the right balance of strength, weight, and cost.
The right thickness is never the same for every job. It changes a lot depending on the load, the environment and how the part is made. Using this step-by-step decision framework can help you make an informed choice. It ensures you select a plate that is strong enough to last but not so thick that it wastes material.
If you have a complex project or need precise calculations, don’t guess. We have experts ready to assist you. Contact us today for expert guidance and ensure your material selection is perfect from the start.
