5251 Aluminium

Designed for general sheet metalwork, 5251 (NS4) is an alloyed non-heat treatable aluminium sheet product which is ideal for applications where a greater degree of formability is required combined with higher mechanical property characteristics.

The alloy is internationally recognised as EN AW 5251 H22 and is AlMg2 hardened to the quarter-hard temper. 5251 aluminium supplied by Thames will meet all appropriate domestic and international standards.

Key Benefits

Typical commercial applications include:

  • Superior corrosion resistance
  • Good surface finish with very good anodising qualities
  • Great combination of formability and strength
  • Very good welding characteristics
Corrosion Resistance

This aluminium sheet alloy offers superior corrosion resistance in typical, industrial and marine environments.

Surface Treatment

5251 provides good anodising properties from both a decorative and technical perspective and finds use in industrial applications and architectural work.


Compared to pure aluminium, 5251 offers higher strength and extra hardness, resulting in improved machinability. Whilst not quite as good as heat-treated alloys, 5251 has reasonable machinability for its intended application. Heat-treated alloys may have greater hardness but reduced formability. Aluminium geometry cutting tools are recommended, which should be run at a moderate speed to avoid edge build-up.


5251 aluminium may be welded by MIG or TIG processes. A good weld should have a strength of up to 160MPa - this is based on the quality of the welding and weld type. Recommended filler metals include 5056A or 5154A for welding to 5251 structures.

5251 Aluminium
5251 pdf
5251 Stock

Product Summary

Product 5251 Aluminium
Type Commercial Aluminium
Availability Sheet
Benefits Superior corrosion resistance, good surface finish with very good anodising qualities, very good marine corrosion resistance, great combination of formability and strength
Applications Boiler making, pressure vessels, architectural fascias and panelling, welded structures, offshore applications
Datasheet 5251 Aluminium - Technical Datasheet
Reference Home/ Products/ Aluminium Alloys/ 5251

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