Why Choose 6061 Marine Grade Aluminum?
6061 marine-grade aluminum alloy is well-regarded for its excellent corrosion resistance and good weldability, making it an effective choice for marine applications. When exposed to saltwater, it naturally forms a dense oxide layer that enhances resistance to corrosion. It performs well during welding—especially when paired with 5356 filler metal. Although welded areas may experience strength reduction, they still outperform some other high-strength alloys under similar conditions.
6061 aluminum plates are commonly used for marine accessories, fittings, gunwales, keels, decks, and structural profiles. Its material characteristics reduce maintenance costs, simplify fabrication, and extend service life.
However, for critical load-bearing structures such as the main hull, most classification societies recommend 5000 series alloys (e.g., 5083, 5086), which offer higher strength and superior stress corrosion cracking resistance in the welded state. Thus, 6061 is better suited for secondary structures, frames, or interior components, rather than large hull panels.
6061 Marine Aluminum Plate Specifications
| Alloy | 6061 |
| Temper | O, T6, T651 |
| Thickness | 3-50 mm |
| Width | 1000-2650 mm |
| Length | 1000-16000 mm |
| Surface Finishes | Anodized, brushed, sandblasted, etc. |
| Classification Society Certificates | ABS, DNV, etc. |
Chemical Composition of 6061 Marine Aluminum (%)
| Alloy | Si | Fe | Cu | Mn | Mg | Cr | Zn | Ti | Other:Each | Other:Total | Al |
| 6061 | 0.4-0.8 | ≤ 0.70 | 0.15-0.4 | ≤0.15 | 0.8-1.2 | 0.04-0.35 | ≤0.25 | ≤0.15 | ≤0.05 | ≤0.15 | Remainder |
Mechanical Properties of 6061 T6 / T651 Marine Aluminum
| Property | O | T6 | T651 | Unit |
| Ultimate Tensile Strength | 18 | 45 | 46 | ksi |
| 124 | 310 | 317 | MPa | |
| Yield Strength | 8 | 40 | 39 | ksi |
| 55 | 276 | 269 | MPa | |
| Shear Strength | 13 | 30 | 30 | ksi |
| 83 | 207 | 207 | MPa | |
| Elongation (2") | 25 | 12 | 11 | % |
| Brinell Hardness | N/A | 95 | 93 | HB |
| Elastic Modulus | 10,000 | 10,000 | 10,000 | ksi |
| 69 | 69 | 69 | GPa |
6061 Marine Plate Thickness Application Chart
6061 aluminum alloy is available in various forms, including rolled sheets, thin plates, and extruded profiles like angles, bars, channels, I-beams, checkered plates, pipes, and tubes. Different thicknesses suit different parts of a ship's construction.
| Thickness Range (mm) | Typical Use | Processing Method | Recommended Temper | Notes |
| 3.0 - 4.0 | Hatch covers, partitions, internal supports | Cutting, bending | T6 | Medium strength, ideal for mid-size components |
| 5.0 - 8.0 | Hull shell, keel, bottom plate | Welding, drilling | T6 / T651 | Good strength and corrosion resistance |
| 10 - 12 | Load-bearing beams, main frame, pontoons | Welding, milling | T651 | For heavy-duty and long-term structures |
| 15 - 20 | Lifting platforms, floating bridges, trusses | Welding, mechanical joint | T651 | High-strength support frameworks |
| ≥25 | Specialized modules, cargo decks | Welding, CNC machining | T651 | For critical high-load structural components |
Comparison: 6061 vs 5xxx Series Marine Alloys
Strength: 6061 can be heat-treated and strengthened, offering higher tensile strength than 5052 (228 MPa).
Corrosion Resistance: Not as robust as 5083/5086, which are preferred for seawater immersion.
Application: 5xxx series are preferred for primary structural components; 6061 is better suited for accessories and non-load-bearing frameworks.
Processing and cost
6061 has excellent processability (especially T651), suitable for CNC precision parts.
The price is slightly higher than 5052, but lower than 7075 (such as T651 sheet is about 26 yuan/kg).
As a professional marine aluminum alloy processing manufacturer, MC Aluminum specializes in the production of 5 series and 6 series marine aluminum alloys. With a rich variety of products, it is exported to more than 40 countries and regions overseas and is highly trusted by customers. For more product information, please feel free to contact us.
Original Source: https://www.marinealum.com/a/6061-marine-grade-aluminum-plate-thickness-guide.html
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