Aluminium Alloys from Thames Stockholders

   5251 (NS4) Aluminium



Designed for general sheet metal work 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 supplied by Thames will meet all appropriate standards, both domestic and international.

5251 aluminium sheet alloy offers very good corrosion resistance in normal, industrial and marine environments. It also has very good anodising properties from both a decorative and technical perspective. When compared to pure aluminium, 5251 offers higher strength and extra hardness which results in improved machinability. Whilst not quite as good as heat-treated alloys, 5251 has quite 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 reasonable speed to avoid edge build-up.

The alloy is easily welded using MIG and TIG processes.

Typical commercial applications for 5251 aluminium alloy include:

  • Boiler making, pressure vessels
  • Architectural fascias and panelling
  • Welded structures
  • Offshore applications
  • Heat transfer devices
  • Cabinets and appliances
  • Chemical and pharmaceutical


  • Very good corrosion resistance
  • Good surface finish with very good anodising qualities
  • Very good marine corrosion resistance
  • Great combination of formability and strength
  • Very good welding characteristics
  • Can be processed to close tolerances
  • Improved machinability properties


  • Ideal for offshore applications
  • Good all-rounder for sheet metal work
  • Economic supply to close tolerances
  • Ideal for welding fabrication
  • Can be supplied with a protective vinyl coating

We stock 5251 aluminium in sheet. We welcome stock enquiries from both domestic and international customers.

  Get in touch...

Thames Stockholders is one of the UK's leading suppliers of aluminium alloy products. To discover more about our products and to receive a competitive quotation, please call us today on +44 (0)20 8805 3282 or click here to contact us.