What is the difference between 4043 and 4047 aluminum?
4047 aluminum alloy and 4043 aluminum alloy are both Al-Si-based welding filler materials, but their compositional differences directly determine their distinct application scenarios.
In simple terms, 4047 is better suited for applications requiring low-temperature welding, high sealing performance, and resistance to hot cracking (such as battery tabs and vacuum insulation layers), while 4043 offers a balanced combination of strength, conductivity, and general-purpose usability (such as automotive components and ship decks).
Let's analyze the differences between the two alloys in more detail.
4047 vs. 4043 Aluminum Properties Comparison Table
| Property/Parameter | 4047 Aluminum Alloy | 4043 Aluminum Alloy | Key Differences & Impact |
|---|---|---|---|
| Silicon (Si) Content | 11-13% (High Silicon) | 4.5-6.0% (Medium Silicon) | 4047 has a lower melting point and better fluidity |
| Magnesium (Mg) Content | ≤0.10% | 0.05-0.20% | 4043 has slight strengthening but requires oxidation control during welding |
| Typical Melting Point | 577°C (Eutectic) | ~600°C | 4047 is better for low-temperature brazing |
| Weld Fluidity | Excellent (High Si improves wetting) | Good | 4047 is better for complex joints or thin-sheet welding |
| Hot Crack Resistance | Superior (High Si absorbs shrinkage stress) | Good | 4047 is less prone to hot cracking |
| Tensile Strength (Annealed) | 130-180 MPa | 130-170 MPa | Negligible difference |
| Electrical Conductivity (IACS) | ~30% | ~35% | 4043 is slightly better (due to lower Si) |
| Typical Applications | Vacuum brazing, heat exchangers, hermetic sealing | General welding (e.g., automotive, marine structures) | 4047 for precision parts, 4043 for structural parts |
Forms of 4047 and 4043 aluminum
1. Welding Wire
Form: Spool, straight length
Diameters: Common sizes include 0.8mm, 1.0mm, 1.2mm, 1.6mm, 2.0mm, 2.4mm
Applications:
4047: Primarily used for TIG (as filler wire), MIG, and laser welding wire feeding
4043: More versatile, widely used for MIG/TIG welding of aluminum structures (e.g., automotive, marine)
Characteristics:
4047 wire offers better fluidity, ideal for thin sheet or precision welding
4043 wire provides slightly higher strength, suitable for medium-load structures
2. Welding Rod
Form: Straight rods, typically 1m in length
Diameters: 2.0mm, 2.5mm, 3.2mm, 4.0mm
Applications:
Mainly for manual TIG (non-consumable electrode) or oxy-acetylene welding
4047: Suitable for vacuum brazing or high-sealing applications
4043: Used for repairing or welding aluminum castings (e.g., engine housings)
3. Shim/Foil
Form: Thin sheets (0.05~0.5mm thickness), preformed rings
Applications:
4047: High silicon content makes it ideal as an interlayer for vacuum brazing (e.g., heat exchanger fin brazing)
4043: Rarely used as foil, mainly for special brazing needs
4. Powder
Form: Spherical or atomized powder (15~150μm particle size)
Applications:
Laser cladding, 3D printing (e.g., selective laser melting/SLM)
4047 powder: Used for high-precision heat sinks or electronic component additive manufacturing
5. Bimetallic Welding Materials
Form: Aluminum-core clad wire (e.g., 4047 outer layer with 4343 alloy)
Applications:
Automotive radiator brazing, balancing fluidity and strength
6. Preplaced Filler Material
Form: Paste (solder paste), adhesive tape (brazing tape)
Applications:
4047 solder paste: For laser brazing of electronic heat sinks (e.g., IGBT modules)
4043 adhesive tape: For local repairs or small component welding
Applications: prefer 4047 or 4043?
Thin sheet/precision welding: Prefer 4047 wire or foil (superior fluidity)
Structural welding: Choose 4043 wire or rod (moderate strength)
Vacuum brazing: Must use 4047 shim or preformed rings
Additive manufacturing: 4047 powder is better for thermal management components
Both alloys' welding material forms comply with AWS A5.10/A5.30 standards. Selection should be based on process (TIG/MIG/laser/brazing) and working conditions (strength, sealing requirements).