5251 Overview

Alloy 5251 is a non-heat treatable rolled product supplied as either sheet or coil. 5251 is stronger than 5005 and is used in applications requiring more structural integrity or impact resistance. 5251 has excellent corrosion resistance, medium static strength, medium to high fatigue strength, good weldability and very good corrosion resistance especially in marine applications.

5251 Mass Conversion Factor: Kilograms (kg) per mm per square metre = 2.70kg

Common Applications

5251 is ideal for general fabrication and manufacturing in both industrial and commercial building applications. Products include marine products such as “tinnies” and marine componentry, boiler making and pressure vessels, fuel tanks, containers, road signs, architectural panelling and irrigation.

The most common tempers for 5251 rolled aluminium are “H32 – ¼ Hard” & “H38 – Full Hard” though both “H34 – 1/2 Hard” and “H36 – 3/4 Hard” are included as alternative tempers.


5251 has excellent weldability by all standard methods especially with GMAW (MIG) and GTAW (TIG). Filler alloy 4043 and 5356 are common filler alloys dependant on alloy joining combinations.


Machinability of 5251 is good whereby the workability improves as tempers harden. Accuracy of machining is managed with high speeds, ample lubrication, sharp tools, positive rakes, adequate clearance and continuous cutting.

Similar Products

Alloy 5052 may be offered as a substitute to 5251 as its more readily available in Australia. These two alloys are similar in composition chemically and mechanically, and are often functionally interchangeable, however they are different allows and therefore need to be considered on a fit for purpose basis by the purchaser. Alloy 5005 has lower strength than 5251, whereas 5083 is stronger.

Chemical Composition Specification (%) Single values are maxima except as noted

Alloy Si Fe Cu Mn Mg Cr Zn Ti Other
Each Total
5052 0.25 0.40 0.10 0.10 2.2-2.8 0.15-0.35 0.10 0.05 0.15
5251 0.40 0.50 0.15 0.1-0.5 1.7-2.4 0.15 0.15 0.15 0.05 0.15

Mechanical Property Specification – Single values are maxima except as noted

Alloy and Temper Thickness mm Tensile Strength Elongation (% min in 50mm)
Over Up to Ultimate Yield
Min Max Min Max
5052-O 1.2 6.3 170 215 65 19
5052-H32 0.63 50 215 265 160 5-11
5052-H38 0.63 3.2 270 220 4
5251-O 0.63 75 170 215 65 15-20
5251-H32 0.63 50 200 255 130 5-11
5251-H34 1.3 25 230 275 180 6-8
5251-H36 0.8 4 250 295 210 4
5251-H38 0.8 3.25 260 225 4

Standards Referenced

AS/NZS 1734:1997 Reconfirmed 2020 – Aluminium and aluminium alloys – Flat sheet, coiled sheet and plate. ASTM B209M-14 – Aluminum and Aluminum Alloy Sheet and Plate

The information in this data sheet document is not an exhaustive statement of all relevant information and is provided by way of general information only. BlueScope Distribution Pty Ltd makes no representation or warranty in relation to this data sheet document or the products or processes it describes, and takes no responsibility for any adverse consequences of any nature which arise as a result of reliance on the information or recommendations contained in it. You must make your own assessment of the information and recommendations contained in this data sheet document, including when necessary seeking specific advice as to the suitably of the products or processes featured in this data sheet document for the purpose for which, and the manner in which, you propose to use them. This may involve further independent analysis and testing.