ER4043 Aluminum Welding Wire
ER4043 is an aluminum-silicon (Al-Si) wire with approximately 5% silicon, offering good weld-pool fluidity, strong welding adaptability, low hot-cracking tendency and a bright bead profile. It is one of the most widely used general-purpose aluminum fillers, kept in stock for both TIG and MIG welding.
ER4043 is one of the most widely used aluminum-silicon filler wires. Its silicon content of about 5% gives good weld-pool fluidity and spread, a low hot-cracking tendency and broad welding adaptability with a wide process window, making it well suited to common 6xxx-series extrusions (such as 6061 and 6063) and to applications with higher demands on weld appearance. Its lower melting point and good wettability give a smooth arc start and a bright, well-formed bead, and it is widely applied in general fabrication and repair. Where the part will be anodized, or where higher joint strength and ductility are required, an aluminum-magnesium wire such as ER5356 is recommended; for specific selection, please contact our technical team.
Specifications
| Classification | AWS A5.10 (ER4043) |
| Alloy system | Al-Si |
| Wire diameter | 1.2 / 1.6 / 2.0 mm |
| Packaging | Layer-wound spool (smooth payoff, tangle-free) |
| Process | TIG / MIG |
Mechanical (typical)
| UTS (as-welded, typ.) | ~165 MPa |
| Elongation (typ.) | ~8% |
| Process behavior | Good fluidity, low cracking |
Chemical composition (AWS A5.10)
| Element | Content % |
|---|---|
| Si | 4.5–6.0 |
| Fe | 0.8 |
| Cu | 0.30 |
| Mn | 0.05 |
| Mg | 0.05 |
| Zn | 0.10 |
| Ti | 0.20 |
| Be | 0.0003 |
| Others (each / total) | 0.05 / 0.15 |
| Al | Remainder |
Chemical composition conforms to the AWS A5.10 ranges; mechanical values are typical, and each batch ships with a quality certificate stating the measured data.
Key characteristics
- Low hot-cracking tendency: a silicon content of about 5% improves weld-pool solidification behavior and reduces solidification cracking, making it a reliable general-purpose choice for everyday aluminum welding.
- Good fluidity and spread: good wettability and ample spread give strong gap-filling capability and a full, smooth bead profile.
- Strong process adaptability: a lower melting point gives smooth arc starts and stable feeding; suited to manual TIG and semi-automatic MIG, with a wide process window and good operating tolerance.
- Bright bead, low spatter: a bright weld color and low spatter give a clean appearance for visible welds and reduce post-weld cleanup.
- Wide base-metal compatibility: suitable for welding a range of cast and wrought aluminum alloys, and especially well matched to common 6xxx-series extrusions.
- Selection note: for high-magnesium base metals (5xxx series) or parts to be anodized, ER4043 can show color mismatch and insufficient joint strength; in such cases an aluminum-magnesium wire such as ER5356 is recommended.
Common uses
- Welding of 6xxx-series aluminum extrusions, such as doors and windows, curtain walls, railings and architectural profiles.
- Aluminum frames, brackets and general components for automobiles, motorcycles and bicycles.
- Welding and repair of cast aluminum parts, such as 356 / A356 and other Al-Si castings.
- Routine welding of heat exchangers, piping, tanks and machined parts.
- Visible welds and repair work that demand good appearance while keeping cracking risk under control.
What base metals it suits
ER4043 suits common 6xxx-series extrusions (such as 6061 and 6063), and can also be used on some 3xxx-series alloys and Al-Si castings; for high-magnesium 5xxx base metals or parts to be anodized, an aluminum-magnesium wire such as ER5356 is generally used instead. Selection should weigh the base-metal grade, the required joint strength and the weld-appearance requirements together. Please share your base-metal grade and application conditions, and our technical team can assist with selection and, where needed, provide guidance on WPS direction.
Other grades
ER4047
About 12% silicon, with higher fluidity and a lower melting point — suited to brazing and thin-sheet welding.
Learn more → Al-Mg · generalER5356
About 5% magnesium, with higher strength and anodizing capability — commonly used for welding 5xxx-series base metals.
Learn more → Al-Mg · high strengthER5183
Higher strength and corrosion resistance — suited to marine and load-bearing structural applications.
Learn more → Al-Mg · elevated-tempER5554
Good resistance to softening at elevated temperature — suited to vessels and piping that stay hot in service.
Learn more →Need an ER4043 quote or sample?
Specializing in aluminum welding wire since 2005, with all five grades kept in stock and a range of diameters in steady supply and prompt replenishment; the layer-wound spools pay off smoothly for stable feeding, and every batch ships with a quality certificate. Please provide your base-metal grade and expected volume, and we will help select the grade and arrange a delivery schedule.
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