When procuring materials for the shipbuilding and heavy marine industry, specifying the correct aluminum alloy is only half the job. Specifying the correct temper is what guarantees structural safety and prevents costly manufacturing failures.
Among the 5000-series alloys, 5083 is the undisputed king of marine applications. Choosing the wrong temper can lead to severe cracking during the bending process or rejection by marine classification societies.
While both belong to the exact same 5083 chemical composition, their processing methods and ideal applications differ significantly. At GNEE, we manufacture and supply certified marine-grade aluminum plates. In this guide, we break down the exact technical differences between 5083 H111 and H112 to help you make the right purchasing decision for your project.
What is 5083 Marine Grade Aluminum Plate?
The 5083 aluminum sheet is a non-heat-treatable alloy containing 4.0% to 4.9% magnesium. It is world-renowned for its exceptional performance in extreme environments. It offers the highest strength of all non-heat-treatable alloys, outstanding weldability, and absolute immunity to seawater and industrial chemical corrosion.
Because it cannot be strengthened by heat treatment (like the 6000 series), its strength is achieved through strain hardening (cold working) and specialized thermal stabilization. This is where the "H" temper designations come into play.
5083 H111 Aluminum Plate
The 5083 H111 aluminum plate is one of the most widely used materials for marine vessel hulls.
Processing: The H111 temper means the plate has been fully annealed (softened) and then subjected to a very slight amount of strain hardening (cold working) during operations like stretching or leveling.
Why choose it? The H111 temper provides an optimal balance. It offers slightly higher yield strength than the fully soft "O" temper, but it retains massive ductility. If your manufacturing process requires complex rotary bending, stamping, or curving (such as shaping the hull of a boat), you must buy 5086 or 5083 H111. It will not crack or fracture under severe bending stress.
5083 H112 Marine Aluminum Sheet
The 5083 H112 aluminum sheet is primarily a structural material.
Processing: The H112 temper indicates an "as fabricated" state. It is typically achieved through hot rolling. There is no deliberate cold working or annealing applied to specifically control its hardness, but there are strict, guaranteed minimum mechanical property requirements.
Why choose it? H112 is highly cost-effective and structurally sound. It is designed for applications where the plate will be used flat or subjected to very minimal bending. If you are building flat bulkheads, diesel engine pedestals, flat deck flooring, or structural frames, 5083 H112 is the perfect choice.
Chemical Composition of 5083 Aluminum Alloy
Since H111 and H112 are just temper variations, they share the exact same chemical makeup. GNEE strictly controls the chemical limits to ensure DNV/ABS certification compliance:
| Element | Content Percentage (%) |
| Magnesium (Mg) | 4.00 – 4.90 |
| Manganese (Mn) | 0.40 – 1.00 |
| Chromium (Cr) | 0.05 – 0.25 |
| Silicon (Si) | Max 0.40 |
| Iron (Fe) | Max 0.40 |
| Zinc (Zn) | Max 0.25 |
| Titanium (Ti) | Max 0.15 |
| Copper (Cu) | Max 0.10 |
| Aluminum (Al) | Balance |
Mechanical Properties: 5083 H111 vs 5083 H112
Below is the standard room-temperature mechanical data for both tempers. (Note: 5083 aluminum plates should never be tested or operated in continuous environments exceeding 65°C / 150°F, as high temperatures lead to magnesium precipitation and stress corrosion cracking).
5083 H111 Mechanical Properties
Tensile Strength: 275 - 350 MPa
Yield Strength (Proof Stress): Min 125 MPa (Typically around 145 MPa)
Elongation: Min 16% (Often reaches 20-23% depending on thickness)
Hardness: ~ 75 HV
5083 H112 Mechanical Properties
Tensile Strength: 270 - 340 MPa
Yield Strength: Min 125 MPa
Elongation: Min 12%
Hardness: ~ 65 - 75 HB
(Conclusion: H111 offers significantly better elongation, making it the superior choice for bending).
Understanding the General "H" Temper System
To help our B2B buyers understand aluminum specifications, here is a quick breakdown of the "H" (Strain Hardened) temper system:
- H1 (Strain Hardened Only): The plate is cold-worked to reach the required strength without any additional heat treatment. (e.g., H18 is fully hard, highly brittle, and unsuitable for bending).
- H2 (Strain Hardened & Partially Annealed): The metal is cold-worked past the desired strength, then partially annealed to soften it slightly and improve ductility.
- H3 (Strain Hardened & Stabilized): The metal is cold-worked and then subjected to a low-temperature thermal treatment to stabilize its mechanical properties. This is crucial for magnesium-alloyed aluminum like 5083 to prevent age-softening at room temperature.
- 5083 H116 & H321 (The Ultimate Marine Tempers): These are specialized tempers for 5083 and 5086 alloys. They are specifically processed to provide maximum resistance to intergranular and exfoliation corrosion in deep-sea, heavy saltwater environments.
Bending Guidelines for 5083 Aluminum Plates
Bending 5083 aluminum requires matching the right temper with the right tooling.
- Do Not Bend: High-hardness tempers like H18 or H38 will crack immediately upon tight bending.
- Safe to Bend: O (Annealed), H111, H112, H32.
- Best Practice: When bending a 5083 H111 marine aluminum sheet, always respect the minimum bend radius. For standard thicknesses, an inner bend radius of 1.5t to 2.5t (where 't' is plate thickness) is recommended to prevent surface fracturing.
Welding 5083 Shipbuilding Aluminum Plate
Both H111 and H112 tempers offer outstanding weldability. Because they are not heavily heat-treated, the heat-affected zone (HAZ) retains a massive amount of the base metal's strength.
Filler Wire Recommendation: For marine applications, always use ER5183 or ER5356 filler wires to match the magnesium content and prevent galvanic corrosion at the weld joint.
Source Your Certified 5083 Aluminum Plates from GNEE
At GNEE, we eliminate supply chain risks for shipyards and heavy fabricators globally. We do not just supply metal; we supply certified reliability.
Partner with GNEE today and receive:
- Marine Certification: Plates supplied with DNV, ABS, LR, or CCS certifications upon request.
- Guaranteed Quality: A free EN 10204 3.1 Mill Test Certificate (MTC) with every order.
- Custom Processing: We offer heavy-duty cutting, slitting, and blanking to your exact CAD specifications, reducing your scrap waste.
- 24-Hour Fast Quote: Send us your inquiry, and our technical sales team will provide a competitive price within 24 hours.
Stop guessing about your materials. Contact GNEE now with your required Alloy, Temper (H111/H112/H116), Dimensions, and Quantity!