Aluminium Alloy Grades Guide: 6063, 6061, 5xxx, and More

If you are trying to identify aluminium scrap — whether you are a contractor sorting offcuts, a demolition lead, or a first-time seller — the alloy series tells you almost everything about value. This guide walks through all seven series, typical applications, and the scrap value bracket we quote in Singapore yards. For our full aluminium scrap buying service see aluminium scrap Singapore. If you are buying virgin aluminium instead, see our aluminium supplier page.

How Aluminium Alloy Numbering Works

The global standard is the Aluminum Association four-digit system. The first digit identifies the principal alloying element:

• 1xxx — commercially pure aluminium (≥99.0% Al)
• 2xxx — copper (Cu) is the main alloying element
• 3xxx — manganese (Mn)
• 4xxx — silicon (Si)
• 5xxx — magnesium (Mg)
• 6xxx — magnesium and silicon (Mg + Si)
• 7xxx — zinc (Zn)
• 8xxx — other elements (e.g. lithium in 8090)

A suffix letter (e.g. 6063-T6) indicates heat treatment. T6 means solution heat treated and artificially aged — the most common temper for structural extrusions.

1xxx Series — Commercially Pure Aluminium

99.0%+ aluminium. Excellent electrical conductivity, corrosion resistance, and formability, but low strength. Common in electrical busbars, chemical tanks, heat exchanger fins, and household foil.

Scrap value (April 2026): S$1.80–2.10/kg when clean and sorted. 1350 (electrical grade) trades at a premium when in recognisable form (busbar, transmission cable).

2xxx Series — Aluminium-Copper (Aerospace)

Contains 3–6% copper. High strength, used in aircraft structures (e.g. 2024 in wing skins, 2017 in rivets). Lower corrosion resistance than other series, so usually clad or painted. Also common in older bicycle frames and some machined parts.

Scrap value (April 2026): S$1.40–1.70/kg. Copper content is economically recoverable but complicates melting, so the discount vs pure series reflects that.

3xxx Series — Aluminium-Manganese (Cans, Roofing)

1–1.5% manganese. Good formability and corrosion resistance. The dominant alloy for beverage cans (3004 body, 5182 lid), industrial roofing sheet, and utility cookware.

Scrap value (April 2026): Used beverage cans (UBC) in baled form around S$1.30–1.60/kg. Sheet roofing offcuts S$1.50–1.80/kg clean.

4xxx Series — Aluminium-Silicon (Welding Wire, Pistons)

4.5–12% silicon. Lowers melting point, excellent castability. Used in welding filler rods, brazing sheet, and piston forgings. 4043 is the most common welding wire you’ll find in a fabrication shop.

Scrap value (April 2026): Clean welding wire offcuts S$1.50–1.80/kg. Pistons classified separately as cast aluminium.

5xxx Series — Aluminium-Magnesium (Marine, Structural)

0.5–5.5% magnesium. Excellent corrosion resistance, especially in seawater, which is why 5083 and 5086 are standard for boat hulls, yacht superstructures, and offshore platform components. Also used in armoured vehicles and bulk tank shells.

Scrap value (April 2026): S$1.70–2.00/kg clean. Marine scrap often arrives painted or anti-fouled, which drops the rate.

6xxx Series — Aluminium-Magnesium-Silicon (Extrusion)

The workhorse series. Mg + Si combination gives good strength, weldability, and extrudability. This is what 95% of aluminium window frames, door frames, louvres, curtain wall mullions, scaffolding, and architectural trim in Singapore are made of.

• 6063 — ‘architectural alloy’ — the default for window frames, door frames, shop-front extrusions. Soft enough for complex extrusion profiles.
• 6061 — higher strength than 6063 — used in structural extrusions, bike frames, truck beds, machined tooling, racing car chassis.
• 6082 — common in European and Singapore structural applications, slightly higher Mg content than 6061.

Scrap value (April 2026): Clean 6063 extrusion (no paint, no thermal break inserts, no screws) is the highest common-grade aluminium we buy, at S$2.00–2.30/kg. 6061 machined turnings are lower, S$1.60–1.90/kg, because of their contamination risk. Painted or anodised 6063 drops to S$1.60–1.80/kg.

7xxx Series — Aluminium-Zinc (Aerospace, High-Strength)

5–7% zinc, often with magnesium and copper. Highest strength of any aluminium series — approaching mild steel. Used in aircraft wing spars (7075), high-end bicycle frames, climbing carabiners, and some firearms. Not great corrosion resistance, so usually anodised or clad.

Scrap value (April 2026): S$1.60–2.00/kg when clean and sorted. Rare in household quantities.

8xxx Series and Others

8xxx covers specialty alloys using other elements. 8090 contains lithium and is used in advanced aircraft. 8011 is a common foil alloy. Also includes some high-pressure die-casting alloys. Scrap buying is specialty — we quote by composition after XRF analysis.

Cast Aluminium (Non-Series)

Cast aluminium does not fit the 1xxx–7xxx wrought system — it uses a three-digit system (e.g. 356, 380, 413). Found in engine blocks, gearbox housings, pistons, wheel hubs, and most die-castings. Typically has higher silicon content and more inclusions than wrought alloys.

Scrap value (April 2026): S$1.00–1.30/kg. Sold as ‘cast’ or ‘mixed cast’ in yard terminology.

Quick ID Field Tests

1. Magnet test: all aluminium alloys are non-magnetic. If a magnet sticks, it’s not aluminium (most likely zinc-coated steel).
2. Spark test: aluminium does not spark on a grinder.
3. Weight test: roughly one-third the density of steel. A piece that looks like steel but feels too light is probably aluminium.
4. Finish: shiny extruded profile with a silver matte or anodised finish = almost certainly 6063.
5. Origin clue: from a window/door = 6063. From a boat = 5083. From a beverage can = 3004/5182. From an engine block = cast 356/380.

How to Maximise Your Aluminium Scrap Payout

• Remove steel screws, hinges, and thermal break inserts from extrusion before weighing in.
• Separate clean extrusion (6063) from cast parts — mixing pulls the whole load down to cast rates.
• Bare metal beats painted — if you can sandblast or strip cheaply, it’s worth doing for volume loads.
• Avoid oil contamination on machined turnings; degrease in batch quantities for a higher quote.
• Check current scrap metal prices before hauling — LME aluminium moves 2–4% week-to-week.

FAQ

Which aluminium alloy is worth the most as scrap?

Among common grades, clean 6063 extrusion (window and door frame material) fetches the highest rate — around S$2.00–2.30/kg as of 27 Apr 2026 in Singapore. Aerospace 2xxx and 7xxx can be worth more when sorted and certified, but are rarely available in retail volumes.

What’s the difference between 6061 and 6063?

6063 is softer and more extrudable — used for complex architectural profiles like window frames and louvres. 6061 has more silicon and magnesium, giving higher strength — used for structural extrusions, bike frames, and machined parts. Scrap value for 6063 is slightly higher because it’s cleaner.

Is beverage-can aluminium worth collecting?

Only in baled volume. Loose cans at S$1.30–1.60/kg means even a large sack only weighs a few kg and nets S$3–5. Bottlers and recycling schemes aggregate at scale — for small volumes, consolidating with other aluminium is more efficient.

Related reading

• Aluminium Scrap Buying Singapore
• Aluminium Supplier Singapore
• Scrap Metal Glossary
• Ferrous vs Non-Ferrous Identification Guide
• Current Scrap Metal Prices
• Clean vs Dirty Scrap Grading Explained