Alloy 5083 in Marine Service
Alloy 5083 is a non-heat-treatable aluminum-magnesium alloy containing about 4.5 percent magnesium, 0.15 percent chromium, and 0.7 percent manganese. It is the strongest of the non-heat-treatable alloys and renowned for outstanding performance in harsh conditions, resisting attack from industrial chemical environments and saltwater. The 5000-series high-magnesium alloys are strengthened by cold working, and the H116 temper is produced by strain hardening with specified stable tensile property limits.
The H116 Temper
H116 applies to 5xxx products with a nominal magnesium content of 3 percent or more that are strain hardened to specified limits and meet required corrosion resistance in accelerated testing, including intergranular and exfoliation corrosion tests. The temper balances high strength with verified corrosion performance for continuous marine service, and the alloy maintains remarkable strength after welding.
Composition and Mechanical Properties
Composition limits are silicon and iron at 0.40 percent each, copper at 0.10 percent, manganese 0.40 to 1.00 percent, magnesium 4.00 to 4.90 percent, chromium 0.05 to 0.25 percent, zinc 0.25 percent, and titanium 0.15 percent. The O, H111, and H112 tempers provide a tensile strength of at least 275 MPa, yield of at least 125 MPa, and elongation of at least 16 percent. The H116 temper provides a tensile strength of at least 305 MPa, yield of at least 215 MPa, and elongation of at least 10 percent, with exfoliation and intergranular corrosion requirements, and the H321 temper provides 305 to 385 MPa tensile with at least 12 percent elongation.
Corrosion Performance in Seawater
5083 withstands corrosion of seawater and marine atmosphere, with a uniform corrosion rate in seawater typically of 0.025 to 0.05 mm per year, lowering oil and maintenance costs and extending service life. Continuous operation is recommended up to about 66 degrees C for the H116 temper. The alloy is also the most used aluminum alloy for cryogenic applications.
Applications in Shipbuilding
Plate 5083 in the H116, H321, and H112 tempers, with widths of 1500 to 2600 mm and thicknesses of 3 to 200 mm, is frequently used to cover the hulls of yachts and cruise ships, and for ship engine bases, decks, sides, and bottom outer plates. It is also used in high-speed ship designs for shipboards, bottom plating, portholes, hydrofoils, and LNG tank-type fluid reservoirs.
Frequently Asked Questions
Q: What is the H116 temper?
A: A strain-hardened temper for 5xxx alloys with 3 percent or more magnesium, meeting intergranular and exfoliation corrosion requirements.
Q: What is the tensile strength of 5083-H116?
A: At least 305 MPa, with a yield of at least 215 MPa.
Q: Is 5083 weldable?
A: Yes, and it retains remarkable strength after welding.
Q: What thickness range is available?
A: 3 to 200 mm with widths of 1500 to 2600 mm.
Q: What is the corrosion rate in seawater?
A: Typically 0.025 to 0.05 mm per year.
Q: What tempers are certified for ships?
A: H116, H321, and H112 with classification society certificates.
For 5083-H116 marine plate quotations with class certification, contact our sales team.