What Is 5083-H22?
5083-H22 is a non-heat-treatable aluminum-magnesium alloy from the 5xxx series. The H22 temper indicates that the material has been strain-hardened to a quarter-hard state and then partially annealed to reduce internal stress while retaining a portion of the strength gained through strain hardening. This places the material between the fully annealed O condition and the fully hardened H28 condition, achieving roughly a quarter of maximum hardness and offering a useful balance of strength, ductility, and corrosion resistance.
Available Forms
5083-H22 is widely produced as plate, tube, and rod. Plate is used in shipbuilding for hulls, decks, and tanks, where its corrosion resistance, formability, and weldability are valued. Tube is suited to ship cooling systems, oil and gas transmission lines, and structural supports that require bending and forming. Rod is used for fasteners, shafts, and structural components in marine equipment, where the temper provides stable dimensional accuracy for turning and milling. Common tube sizes range from about 3 mm to 2500 mm outside diameter with wall thicknesses of about 0.2 to 150 mm; round rod is commonly available from 5 mm to 420 mm diameter, and square bar from 6.35 mm x 6.35 mm up to 150 mm x 150 mm, subject to supplier capability.
Chemical Composition
5083 is primarily aluminum with magnesium as the main alloying element at 4.0-4.9%, manganese at 0.4-1.0%, and chromium at 0.05-0.25%, together with small amounts of silicon, iron, copper, zinc, and titanium. The high magnesium content is what gives the alloy its outstanding resistance to seawater and industrial chemicals.
Mechanical and Physical Properties
Published reference values for 5083-H22 include an ultimate tensile strength of about 305-380 MPa, a yield strength of at least 215 MPa, elongation of roughly 8.8%, Brinell hardness around 89 HB, and a fatigue strength of about 190 MPa. Physical reference values include a density of about 2650 kg/m3, melting range around 580-640 degrees C, thermal conductivity of about 120-121 W/m-K, a coefficient of thermal expansion of about 25 x 10-6/K, electrical resistivity of about 0.58 x 10-6 ohm-m, and an elastic modulus of about 72 GPa. Because of the high magnesium content, service temperature is generally limited to about 65 degrees C where corrosion resistance is the governing factor.
Applications
5083-H22 is widely used in marine structures including ship hulls, decks, and storage tanks; pressure vessels for chemical and gas storage; cryogenic tanks and pipelines; and structural components such as frames, brackets, and supports. Its combination of corrosion resistance, weldability, and moderate strength makes it a first choice wherever long-term exposure to seawater is expected.
Fabrication and Limitations
The alloy is suitable for stamping and stretching and welds readily with MIG and TIG processes using 5xxx-series filler such as 5183, although strength in the heat-affected zone may be lower than in the parent material. Machining generally requires specialized tooling because of the alloy's toughness. Because magnesium content exceeds 3.5%, service above about 65 degrees C should be avoided where stress-corrosion resistance is required, and cold working should be carried out carefully. Compared with the H32 temper, H22 offers slightly different strength and elongation characteristics: H22 is typically higher in tensile strength while H32 offers better formability; the final choice depends on whether strength or forming ease dominates the application.
FAQ
Q: What does H22 mean in 5083-H22?
A: H22 means the material was strain-hardened to a quarter-hard state and then partially annealed, giving a balance of strength and formability between the O and H28 conditions.
Q: Is 5083-H22 suitable for seawater?
A: Yes. Its high magnesium content gives it excellent resistance to seawater and industrial chemicals, which is why it is standard in marine engineering.
Q: Can 5083-H22 be welded?
A: Yes. MIG and TIG welding with a 5xxx-series filler such as 5183 is recommended, though the heat-affected zone may show reduced strength.
Q: What is the tensile strength of 5083-H22?
A: Published reference values are about 305-380 MPa ultimate tensile strength with a yield strength of at least 215 MPa; confirm actual values on the mill certificate.
Q: What forms is 5083-H22 available in?
A: Plate, tube, and rod, including round rod and square bar, with sizes depending on the supplier's mill capability.
Q: Is 5083-H22 good for cryogenic service?
A: Yes. 5xxx alloys such as 5083 retain toughness at low temperatures and are commonly used for cryogenic tanks and pipelines.
