The 4xxx wrought aluminum alloy series is also known as the 4000 series. These alloys are primarily aluminum-silicon alloys with or without minor impurities. Also, it’s the only series in the Aluminum Association Inc designation to have well-defined heat-treatable and non-heat-treatable alloys.

Aluminum 4xxx Series Alloy Characteristics

Some key characteristics of the 4000 series aluminum alloys are –

• Lower melting point
• Provides good weldability as fillers
• Excellent wear resistance
• Heat treatability is based on impurities
• Ultimate tensile strength of 25ksi to 55ksi
• Increased strength after heat treatment
• Poor thermal expansion
• Improved fluidity
• Black anodizedfinishing

Non-heat treatable alloys in the series have aluminum and silicon with almost no traces of impurities. But the presence of copper and magnesium can enable alloys to become heat treatable.

Common Aluminum Grade 4xxx Alloys

Nearly 12% Silicon (Si) can be added to aluminum as the major alloying element. But the percentage can vary from as low as 0.6% up to as high as 21.5% in some cases.

The most used commercial alloys of grade 4xxx alloys are –

• Grade 4032 (11.0% – 13.5% Si)
• Grade 4043 (4.5% – 6.0% Si)
• Grade 4045 (9.0% – 11.0% Si)
• Grade 4047 (11.0% – 13.0% Si)
• Grade 4145 (9.3% – 10.7% Si)
• Grade 4343 (6.8% – 8.2% Si)
• Grade 4643 (3.6% – 4.6% Si)

Magnesium (Mg), Copper (Cu), Nickel (Ni) and Beryllium (Be) are also present in some alloys. But their percentages are relatively lower compared to Silicon.

Aluminum Grade 4xxx Series Alloy Applications

The 4000 series alloys are available as sheets, sheet plates, and coils. However, rare forms include bars, castings, pipes, strips, tubes, and wires. Manufacturing usable wires from this series is difficult due to the lower melting points.

Welding

Lower melting points with improved fluidity are desirable in brazing and fusion welding. Therefore, the alloy series is predominantly the best filler material. However, heat-treatable 4032 and 4145 alloys are mostly used for post-weld thermal treatments.

Architecture

Anodic oxide finishing on these alloys imparts beautiful dark grey or charcoal surfaces. Many decorative and architectural applications use these alloys for appealing looks.

Engine

Sufficient resistance to wear enables some non-heat-treatable alloys for mechanical uses. Some commercial applications include manufacturing forged engine pistons. Also, 4xxx alloys can replace 1xxx alloys due to improved mechanical properties.

Which Aluminum Alloy is the Best for Your Project?

Grade 4xxx alloys have limited yet desired applications across the industry. However, other wrought aluminum alloys could be a better choice unless you are using the 4000 series alloy as a filler for welding. Also, consider aluminum die-casting manufacturing as a viable alternative for large-volume production.

Sunrise metal provides die casting and CNC machining services to meet your manufacturing needs. Feel free to contact us to decide on the ultimate aluminum alloys for your upcoming projects.