Strip and foil
Thin 4047 strip and foil, typically O temper, slit to width for shims, preforms and filler layers.
Al-Si brazing alloy sheet
4047 Aluminium Sheet, Plate & Coil
4047 is an aluminium-silicon alloy with 11 – 13 % silicon, close to the eutectic composition, so it melts at about 577 – 582 °C, well below most aluminium base metals. It is used as braze cladding, filler foil and shims, and as welding filler. Metline supplies 4047 sheet, plate, strip and foil cut to your sizes, certified to the specification you name, worldwide.
- Alloy
- 4047 (Al-12Si)
- Melting range
- about 577 – 582 °C
- Tempers
- O, H14, H18, F / H112
- Uses
- Brazing clad, filler, welding
What is 4047 aluminium?
Silicon lowers the melting point of aluminium, reaching a minimum at the eutectic of about 12.6 % silicon and 577 °C. 4047, at 11 – 13 % silicon, sits almost exactly there: it melts over a very narrow range and flows freely when molten. That makes it an ideal filler for joining aluminium parts that melt at 600 – 660 °C.
In sheet and strip form, 4047 has three main jobs. It is roll-bonded as a thin cladding layer onto a 3xxx core to make brazing sheet for heat exchangers; it is cut into foil, shims and preforms that are placed in joints before furnace brazing; and it is used as a filler alloy (ER4047) for welding where low shrinkage and good fluidity reduce cracking.
As a standalone structural material 4047 is not attractive: it is not heat-treatable, its strength is modest and the high silicon makes it brittle in thicker sections and abrasive to machine. Buyers therefore choose 4047 sheet for what it does at brazing temperature, not for its room-temperature properties.
4047 chemical composition (wt %)
| Element | Minimum | Maximum | Comment |
|---|---|---|---|
| Silicon (Si) | 11.0 | 13.0 | Near-eutectic; sets the melting range |
| Iron (Fe) | — | 0.8 | |
| Copper (Cu) | — | 0.30 | |
| Manganese (Mn) | — | 0.15 | |
| Magnesium (Mg) | — | 0.10 | Kept low for flux brazing; vacuum-brazing variants add Mg |
| Zinc (Zn) | — | 0.20 | |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder |
Aluminum Association limits. EN AW-4047A (AlSi12(A)) is the European equivalent with similar limits. For vacuum brazing, magnesium-bearing Al-Si fillers (for example the 4104 type) are used instead.
Physical properties and brazing data
Typical physical properties
- Density
- about 2.66 g/cm³
- Solidus / liquidus
- about 577 °C / 582 °C
- Typical brazing temperature
- about 590 – 605 °C
- Coefficient of thermal expansion
- about 20 µm/m·°C, lower than pure aluminium because of the silicon
- AWS brazing classification
- BAlSi-4 (AWS A5.8)
- AWS welding classification
- ER4047 / R4047 (AWS A5.10)
Brazing base metals must have a solidus comfortably above the brazing temperature. 1xxx, 3xxx (such as 3003) and low-magnesium 6xxx alloys (such as 6063 and 6951) are routinely brazed with 4047; high-magnesium 5xxx alloys and most 2xxx and 7xxx alloys are not, because they either melt too low or form oxides that flux cannot remove.
4047 forms and tempers
Sheet
Sheet for cutting brazing preforms, washers and discs, in O, H14 or H18.
Plate and slabs
Thicker 4047 for clad-liner use in roll bonding, or as cast and rolled blanks.
Clad brazing sheet
A 3003 or modified 3xxx core with a 4047 or 4343 / 4045 skin on one or both sides, used for radiator, condenser and evaporator parts.
4047 supply range
Supply range
- Foil and strip
- About 0.05 – 0.5 mm, slit widths to suit
- Sheet
- About 0.5 – 6 mm
- Plate
- Thicker gauges on request
- Processing
- Slitting, cut-to-length, stamping of discs, rings and preforms
4047 weighs about 2.66 kg per m² per millimetre:
| Thickness (mm) | kg per m² | 1220 × 2440 mm (kg) | 1500 × 3000 mm (kg) |
|---|---|---|---|
| 0.1 | 0.27 | 0.8 | 1.2 |
| 0.2 | 0.53 | 1.6 | 2.4 |
| 0.5 | 1.33 | 4.0 | 6.0 |
| 1 | 2.66 | 7.9 | 12.0 |
| 1.5 | 3.99 | 11.9 | 18.0 |
| 2 | 5.32 | 15.8 | 23.9 |
| 3 | 7.98 | 23.8 | 35.9 |
| 4 | 10.6 | 31.7 | 47.9 |
| 5 | 13.3 | 39.6 | 59.9 |
| 6 | 16.0 | 47.5 | 71.8 |
| 10 | 26.6 | 79.2 | 119.7 |
Using 4047 in brazing
- CleanDegrease all parts; remove heavy oxide by etching or mechanical cleaning.
- Fit upKeep joint clearances small, typically about 0.05 – 0.25 mm, so capillary action draws filler into the joint.
- Flux or vacuumIn controlled-atmosphere brazing, apply non-corrosive fluoride flux; for vacuum brazing use a magnesium-bearing filler rather than standard 4047.
- HeatRaise parts uniformly to about 590 – 605 °C and hold briefly; avoid overheating, which causes erosion of thin base metals.
- InspectCheck fillet formation and leak-test heat exchangers.
Applications
- Automotive radiators, condensers, evaporators, charge-air coolers and oil coolers
- HVAC and refrigeration heat exchangers
- Brazed cold plates and battery-cooling parts for electric vehicles
- Filler shims and preforms for furnace and torch brazing
- Welding filler (ER4047) for 6xxx and cast alloys where crack resistance and fluidity are needed
How to order 4047 sheet and foil
- SpecifyForm (foil, strip, sheet, plate or preforms), thickness, width or size, temper, quantity, brazing process and any specification (AWS A5.8, EN 573-3 or customer standard).
- QuoteWe confirm availability, tolerances, certification, packing and delivery terms (EXW, FOB, CIF or DAP) for your destination.
- ProcessMaterial is slit, cut or stamped to size, interleaved and inspected for thickness and surface.
- DocumentEach delivery carries a mill test certificate to EN 10204 3.1 with the cast analysis and mechanical results for the lot; third-party inspection can be arranged on request.
- ShipSheets are interleaved or film-protected, packed on pallets or in seaworthy wooden cases, and shipped by sea or air to your port or door.
References and standards
- AWS A5.8 – Specification for Filler Metals for Brazing and Braze Welding
- AWS A5.10 – Welding Consumables: Wires and Rods for Aluminum and Aluminum Alloys
- EN 573-3 – Aluminium and aluminium alloys: chemical composition and form of wrought products
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets)
- ASM Handbook, Volume 6 – Welding, Brazing and Soldering
4047 aluminium (aluminum) sheet: frequently asked questions
What is 4047 aluminium used for?
Mainly brazing: as cladding on brazing sheet, as filler foil, shims and preforms, and as ER4047 welding filler.
What is the melting point of 4047?
About 577 °C solidus and 582 °C liquidus. Brazing is usually done at about 590 – 605 °C.
What is the difference between 4047 and 4045?
4045 has about 9 – 11 % silicon and a wider melting range; 4047 has 11 – 13 % silicon, melts lower and flows more freely. Both are used as braze cladding.
Can 4047 be used structurally?
It is not a good structural alloy: strength is modest and it cannot be heat-treated. Its value is as a filler.
Is 4047 suitable for vacuum brazing?
Standard 4047 is used mainly with flux (CAB). Vacuum brazing normally uses magnesium-bearing Al-Si fillers.
Need 4047 sheet, strip or foil?
Send form, size, quantity and brazing process. We will reply with availability and a delivered price.
