What is the difference between 5083 H116 and H321 aluminum?
Last Updated :
5083 H116 and H321 aluminum plates are both marine-grade aluminum alloy materials, but there are some differences in their production processes, performance characteristics, and applicable scenarios.
The main differences between 5083-H116 and 5083-H321 aluminum alloys lie in their processing methods, mechanical properties, and application suitability. Both are marine-grade alloys with the same chemical composition, but their tempering processes differ, resulting in distinct performance characteristics.
5083 H116 and H321 are non-heat-treatable variants of the 5xxx series aluminum alloy (Al Mg4.5Mn0.7). They share the same basic chemical composition but differ in cold working and thermal stabilization processes. Critically, H321 exhibits excellent resistance to exfoliation and intergranular corrosion, making it the preferred temper for the harshest marine and chemical environments.
While 5083 H116 and H321 have the same alloy composition and generally good overall properties, the additional thermal stabilization treatment in H321 slightly improves its mechanical strength, enhances ductility, and significantly boosts resistance to exfoliation and intergranular corrosion. Therefore, H116 is typically used in standard marine and structural applications, while H321 is specifically suited for highly corrosive, underwater, or stress-sensitive environments.
5083 H116 vs H321 Comparison Table
| Aspect | 5083-H116 | 5083-H321 |
| Processing | Strain-hardened only | Strain-hardened + stabilized |
| Strength | Slightly higher tensile strength | Better fatigue resistance |
| Stability | Residual stress present | Reduced stress, dimensional stability |
| Best For | Non-welded marine structures | Welded/dynamic-load components |
| Corrosion Resistance | Higher magnesium content, superior seawater corrosion resistance, suitable for long-term underwater environments | Standard corrosion resistance, enhanced stability |
| Machinability | Poorer cold workability, requires strict control of forming processes | Better weldability and formability, suitable for complex structures |
5083 H116 vs H321 Mechanical Properties
| Property | H116 | H321 |
| Tensile Yield Strength (0.2% PS) | ~230 MPa (33 ksi) | ~240 MPa (35 ksi) |
| Ultimate Tensile Strength (UTS) | ~320 MPa (47 ksi) | ~330 MPa (48 ksi) |
| Elongation at Break | ~12 % | ~13 % |
| Brinell Hardness (HB) | 83 | 89 |
| Modulus of Elasticity | ~68 GPa | ~68 GPa |
The H321 temper typically provides a modest increase in strength (≈5 %) and slightly better ductility compared to H116 due to the stabilization heat treatment.
5083 H116 vs H321 Temper Definitions
- H116: Strain-hardened by cold working, partially annealed to optimize strength and ductility; must pass ASTM G66/67 exfoliation and intergranular corrosion tests .
- H321: A stabilized temper involving strain hardening plus low-temperature thermal treatment to convert β-Mg2Al3 precipitates into more stable forms, reducing susceptibility to stress corrosion cracking
5083 H116 vs H321 Corrosion Resistance
Both alloys offer excellent resistance to saltwater corrosion, but H321 performs better in post-weld environments due to lower residual stress.
H116 is optimized for direct load-bearing applications (such as hulls), while H321's stabilization characteristics minimize stress corrosion cracking at welded joints.
- 5083 H116: Corrosion resistance rated as "excellent," suitable for marine applications, but prolonged exposure to high temperatures may reduce performance.
- 5083 H321: Enhanced resistance to exfoliation and intergranular corrosion, verified through mandatory ASTM G66 (exfoliation) and G67 (IG corrosion) tests; suitable for the most corrosive underwater or chemical environments.
5083 H116 vs H321 Processing Methods
This temper process involves strain hardening (cold working) without subsequent heat treatment. It retains residual stress from the cold working process, resulting in higher hardness and strength. Specifically designed for marine applications and rigorously tested for corrosion resistance (e.g., intergranular and exfoliation tests).
Magnesium content: ≥4%
Suitable for continuous use up to 66°C.
This temper combines strain hardening and stabilization treatment (low-temperature annealing). The stabilization process reduces residual stress, improves dimensional stability, and enhances resistance to thermal aging softening. This makes it ideal for welded structures under dynamic loads.
5083 H116 vs H321 Processing and Alloy Control Requirements
5083 H116 Temper
- Specifically designed for high magnesium content (4.0%~4.9%), requiring strict control of magnesium distribution and strain hardening processes during production to enhance corrosion resistance.
- Special stabilization treatment is required after final annealing to optimize long-term stability in marine environments.
5083 H321 Temper
- Material properties uniformity is ensured through carefully adjusted hot and cold rolling processes at specific temperatures, combined with stretch straightening treatment.
- The process emphasizes a balance between thermal and mechanical treatments to stabilize mechanical performance.
5083 H116 vs H321 Applications
- 5083 H116: Prioritized for yacht hulls, decks, and other corrosion-prone parts in direct contact with seawater, such as prolonged immersion or high salt spray environments.
- 5083 H321: Suitable for superstructures, cabin frameworks, and components with higher requirements for overall stability and welding efficiency.
5083-H116 Applications
- Ship decks, large storage tanks, bridge bearings.
- Structures requiring high strength without complex welding.
5083-H321 Applications
- Aircraft fuel tanks, rail vehicle bodies, chemical pipelines.
- Welded components subjected to cyclic stress (e.g., ship welding parts).
5083 H116 vs H321 Typical Applications in Marine Field
| Environment | Preferred Temper | Examples |
| Marine hull plating | H116 | Ship decks, hull plating |
| Submerged structures | H321 | Offshore platforms, underwater piping |
| Pressure vessels/cryogenics | H116 | Tanks, cryogenic containers |
| Extreme/exposed marine | H321 | Salvage pontoons, heavy-load ship components |
H321 is generally chosen over H116 when the service environment demands the utmost corrosion stability under cyclic loading or high stress.
5083 H116 vs H321 Weldability
- Both alloys exhibit good weldability, but the stabilization characteristics of H321 ensure more consistent post-weld performance.
- The heat-affected zones (HAZ) in both tempers undergo annealing after welding, but the lower residual stress in H321 reduces the risk of distortion.
Weldability and Stress Corrosion Cracking
- Both tempers retain the inherent excellent weldability of the 5xxx series alloys, with minimal risk of hot cracking.
- H321's stabilized precipitate structure reduces the risk of post-weld stress corrosion cracking and sensitization, which is particularly important for welded marine or cryogenic structures.
5083 H116 vs H321 Cost
- H116 has a slightly higher production cost due to its more complex processing, but its long service life in harsh environments can reduce maintenance costs.
- H321, with its cost-effectiveness and mature processing technology, offers advantages in scenarios with medium to low corrosion risk.
The choice between the two should consider corrosion protection requirements, structural complexity, and budget. For high-strength corrosion environments, H116 is preferred, while H321 is more suitable for general shipbuilding structures.
Recommended Product: 5083 marine grade aluminium checkered tread plate sheet 5083 5383 O H112 Marine Grade Aluminum Bars 5083 Marine Grade Aluminum Pipe Tube 5083 Marine Grade Aluminum Plate Sheet 5083 H321 Aluminum Plate 5083 H116 Aluminum Plate Aluminium 5083 H111 Aluminum 5083 H112 5083 Aluminum Flat Bar 5083 Aluminum Bar 5083 Aluminum Round Bar 5083 Aluminum Square Tubes 5083 H131 Aluminum Plate