Sawn round slugs
Cut from extruded 6063 rod; the usual route for thicker slugs and heat-sink blanks, giving a consistent structure and accurate weight.
Heat-treatable slugs for housings and heat sinks
6063 Aluminium Slugs
6063 aluminium slugs are annealed blanks that flow easily under an impact press and can then be aged for strength, which makes them a common choice for cold-forged heat sinks, LED and motor housings and decorative anodised parts. 6063 sits between soft 1xxx/3xxx slugs and the stronger 6061: easier on the tools, with good thermal conductivity and a bright anodised finish. Metline supplies 6063 slugs punched or sawn to drawing, worldwide.
- Alloy
- 6063 (Al-Mg-Si)
- Supply temper
- O (annealed)
- Finished part
- T4, T5 or T6
- Standard
- EN 570 · EN 573-3
Why use 6063 for impact extrusion?
6063 contains less magnesium and silicon than 6061 and almost no copper, chromium or manganese. That leaner chemistry gives it a lower flow stress in the annealed state, so it fills complex dies with less force, while still responding to ageing after forming.
Impact extrusion and cold forging turn a slug into a finished part in a fraction of a second. With 6063 the process can produce thin fins, deep cups and fine detail that would overload tooling in 6061, and the finished part can be aged to T5 or T6 for useful stiffness and hardness. Because 6063 is also one of the most thermally conductive heat-treatable alloys, it is widely used for forged pin-fin and plate-fin heat sinks, LED lamp bodies and electronic cooling parts.
The same low alloy content gives 6063 an even, bright surface after anodising, so it suits visible consumer parts such as torch bodies, pen and cosmetic cases and appliance trims. Where a part has to carry heavy loads or pressure, 6061 is the better slug; where the part is a simple can or tube, 1070 or 3003 slugs cost less and run faster.
6063 chemical composition (wt %)
Registered Aluminum Association limits, matched by EN 573-3 for EN AW-6063. The low iron, copper and chromium limits are what keep the anodised surface clean and the conductivity high. Actual analysis appears on the mill test certificate for each lot.
| Element | Minimum | Maximum | Role in the alloy |
|---|---|---|---|
| Silicon (Si) | 0.20 | 0.60 | Forms Mg2Si with magnesium |
| Iron (Fe) | — | 0.35 | Kept low for a bright, even surface |
| Copper (Cu) | — | 0.10 | Impurity; low copper helps corrosion resistance |
| Manganese (Mn) | — | 0.10 | Impurity |
| Magnesium (Mg) | 0.45 | 0.90 | Main strengthening element with Si |
| Chromium (Cr) | — | 0.10 | Impurity |
| Zinc (Zn) | — | 0.10 | Impurity |
| Titanium (Ti) | — | 0.10 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder |
6063 properties from slug to finished part
The slug is delivered annealed; the finished part is usually aged. Typical values below come from Aluminum Association and ASM data and describe the material, not a guaranteed minimum for any product form.
| Temper | Stage | Tensile strength | Yield strength | Elongation | Hardness |
|---|---|---|---|---|---|
| O | Slug supply condition | 90 MPa | 48 MPa | 22 – 25 % | 25 HB |
| T4 | Solution treated, naturally aged | 172 MPa | 90 MPa | 22 % | 46 HB |
| T5 | Aged after forming (no separate solution treatment) | 186 MPa | 145 MPa | 12 % | 60 HB |
| T6 | Solution treated and artificially aged | 241 MPa | 214 MPa | 12 % | 73 HB |
Physical properties (typical)
- Density
- 2.69 g/cm³
- Modulus of elasticity
- 68.9 GPa
- Thermal conductivity
- About 218 W/m·K (O), 209 (T5), 200 (T6)
- Electrical conductivity (T6)
- About 53 % IACS
- Thermal expansion (20 – 100 °C)
- 23.4 µm/m·°C
- Melting range
- 616 – 654 °C
T5 on an impact part means it was cooled from the forming operation and aged. Cold impacts gain little heat in the press, so most users solution-treat and age to T6 when strength matters.
Slug shapes and cutting routes
Punched slugs
Blanked from plate or thick strip; economical for thinner slugs in long runs, followed by tumbling to remove burrs.
Holed slugs
With a punched or drilled centre for forward-extruded tubes and sleeves.
Square and rectangular slugs
For non-round housings, battery and electronic cases.
Preformed slugs
Upset, chamfered or domed blanks that start metal flow evenly in the die.
Discs for spinning and drawing
Thin 6063 circles for spun reflectors, lamp shades and decorative covers.
Annealing, surface treatment and lubrication
Slug preparation is what lets 6063 flow into fine fins without tearing. A full anneal (typically about 415 °C followed by slow cooling) brings the slug to the O temper and evens out the grain. Coarse grain in a slug shows up later as an orange-peel surface on the part, so annealing cycles and the structure of the source bar both matter.
After annealing, slugs are tumbled or shot-blasted to remove burrs and give a matt surface that holds lubricant, then coated with a dry lubricant such as zinc stearate. Whether lubrication is done by the supplier or at the press is agreed per order. Prepared slugs are packed dry, because moisture or contamination degrades the lubricant film.
Typical quality checks
- Weight
- Sampled per lot against the agreed target and tolerance
- Dimensions
- Diameter, thickness, flatness and hole position where applicable
- Hardness
- Brinell or Rockwell check to confirm the annealed condition
- Surface
- Free from burrs, laps, oil and heavy oxide
- Documentation
- EN 10204 3.1 certificate with cast analysis
Standards and equivalent designations
| System | Designation | Related standard |
|---|---|---|
| Aluminum Association / UNS | 6063 / A96063 | Source rod ASTM B221 |
| European (EN) | EN AW-6063 (AlMg0.7Si) | EN 570 slugs; EN 573-3 composition; EN 755 rod |
| ISO | AlMg0.7Si | ISO 209 |
| German Werkstoff | 3.3206 | — |
| Japan (JIS) | A6063 | JIS H4040 (rod) |
| India (IS) | 63400 | IS 733 |
EN 570 sets inspection and delivery conditions and tolerances on dimensions and form for impact extrusion slugs from wrought products. Outside Europe, most buyers order to their own drawing and certify the alloy to the source product standard.
Supply range and slug weights
Supply options
- Shape
- Round, holed, square, rectangular or to drawing
- Size
- Diameter, thickness and weight to the press user's drawing
- Temper
- O as standard; F or other tempers on request
- Surface
- Tumbled, shot-blasted, with or without lubricant
- Packing
- Sealed cartons, drums or crates with desiccant, labelled by lot
Weight of a solid round slug is π/4 × D² × t × 2.69 g/cm³. Reference weights in grams:
| Diameter (mm) | t = 5 mm (g) | t = 10 mm (g) | t = 15 mm (g) | t = 20 mm (g) | t = 30 mm (g) |
|---|---|---|---|---|---|
| 20 | 4 | 8 | 13 | 17 | 25 |
| 30 | 10 | 19 | 29 | 38 | 57 |
| 40 | 17 | 34 | 51 | 68 | 101 |
| 50 | 26 | 53 | 79 | 106 | 158 |
| 60 | 38 | 76 | 114 | 152 | 228 |
| 80 | 68 | 135 | 203 | 270 | 406 |
| 100 | 106 | 211 | 317 | 423 | 634 |
| 120 | 152 | 304 | 456 | 608 | 913 |
| 150 | 238 | 475 | 713 | 951 | 1426 |
Parts made from 6063 slugs
- Thermal management: cold-forged pin-fin and plate-fin heat sinks, LED lamp bodies, CPU and power-electronics coolers
- Electrical: motor housings, sensor bodies, connector shells and enclosures
- Consumer goods: torch bodies, pen and cosmetic cases, speaker and camera parts, appliance trims
- Automotive: lighter housings, sensor cups and covers where 6061 strength is not needed
- Packaging and containers: premium bottles and canisters with anodised finishes
6063 or 6061 slugs?
| Factor | 6063 slug | 6061 slug |
|---|---|---|
| Flow stress (O temper) | Lower; fills fins and thin walls more easily | Higher; more press force |
| Typical T6 tensile strength | About 241 MPa | About 310 MPa |
| Thermal conductivity (T6) | About 200 W/m·K | About 167 W/m·K |
| Anodised appearance | Very bright and even | Good |
| Tool life | Longer | Shorter |
| Choose it for | Heat sinks, housings, decorative parts | Load-bearing and pressure parts |
For a fuller comparison of the two alloys, see our 6061 vs 6063 article.
How to order 6063 slugs
- SpecifyDrawing or diameter, thickness, hole and weight target; hardness limit; surface treatment and lubricant; quantity.
- ConfirmWe confirm cutting route, tolerances, certificate and delivery terms (EXW, FOB, CIF or DAP).
- TrialA trial lot for new tooling lets your press team confirm fill and finish before volume orders.
- ShipSlugs travel in sealed, moisture-protected packing with the EN 10204 3.1 certificate.
References and standards
- EN 570 – Aluminium and aluminium alloys: impact extrusion slugs obtained from wrought products, specifications
- EN 573-3 – Chemical composition and form of wrought products
- ASTM B221 – Extruded Bars, Rods, Wire, Profiles, and Tubes
- ASM Handbook Vol. 14A – Cold Extrusion of Aluminium Alloys
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
6063 aluminium (aluminum) slugs: frequently asked questions
Is 6063 good for cold-forged heat sinks?
Yes. It flows well in the annealed state, so thin fins and pins form cleanly, and its thermal conductivity of roughly 200 – 218 W/m·K (depending on temper) is high for a heat-treatable alloy. Pure 1050 or 1070 conducts a little better but gives much softer parts.
What temper are 6063 slugs supplied in?
Normally O (fully annealed), which gives the lowest flow stress and a uniform grain. The finished part is then aged, or solution treated and aged, to T5 or T6.
How strong is a 6063 impact after heat treatment?
Typical T6 values are about 241 MPa tensile and 214 MPa yield strength, with around 73 HB hardness. T5 parts are lower, at roughly 186 MPa tensile.
Why does surface grain matter on slugs?
Coarse grain in the slug can show as orange peel on formed or anodised surfaces. Controlled annealing and fine-grained source bar keep the part surface smooth.
Can you supply lubricated slugs?
Yes, slugs can be supplied tumbled or shot-blasted and coated with a dry lubricant such as zinc stearate, or bare for lubrication at your press, by agreement.
Do you ship 6063 slugs internationally?
Yes. Metline exports slugs worldwide from Mumbai with mill certificates and sealed, moisture-protected packing.
Planning a 6063 impact or forged heat sink?
Send your slug drawing, quantity and destination, and we will reply with route, tolerances and a delivered price.
