4643 aluminum alloy is a 4000-series Al-Si-Mg welding filler metal, developed as a modification of 4043 with a magnesium addition (0.10-0.30% Mg). The Mg content enables the weld deposit to respond to post-weld aging, producing higher joint strength than 4043 on 6xxx series base metals. Linsy supplies 4643 aluminum filler wire and rod in TIG cut-length and MIG spooled formats, with custom diameters, MTC reports, and SGS testing available on request.
Beschikbare formulieren: TIG filler rod / MIG welding wire / bare rod
Common diameters: 0.8 – 4.0 mm
Base metal compatibility: 6061 / 6063 / 6082 / 6A02
Kwaliteitsdocumenten: MTC-rapport bij elke bestelling, SGS-keuring op verzoek
4643 aluminum alloy (UNS A94643) is a 4000-series aluminum welding filler metal, primarily composed of aluminum, silicon (3.6-4.6%), and magnesium (0.10-0.30%). It was developed as a modification of the well-known 4043 filler alloy, with the key addition of magnesium to enable post-weld age hardening of the weld deposit. This makes 4643 uniquely suited for structural welding of 6xxx series aluminum alloys where higher joint strength is required after heat treatment.
Unlike 4043, whose weld deposit remains non-heat-treatable, 4643 weld deposits can be solution heat treated and artificially aged after welding, allowing the weld joint to more closely match the T6 properties of the 6xxx base metal. This characteristic is particularly valuable for heavy-section welds on 6061, 6063, and 6082 components that will undergo post-weld heat treatment.
4643 is classified under AWS A5.10/A5.10M as ER4643 and is supplied primarily as bare welding wire and rod for gas tungsten arc welding (GTAW/TIG) and gas metal arc welding (GMAW/MIG). It retains the excellent fluidity, crack resistance, and corrosion resistance of 4043, while offering improved mechanical properties in the as-welded and post-weld aged conditions.
Linsy supplies 4643 aluminum primarily as welding filler wire and rod. Diameters, spool sizes, and cut lengths can be tailored to your welding process and project requirements.
| Formulier | Specificatie | Diameter (mm) | Lengte (mm) | Oppervlak |
|---|---|---|---|---|
| 4643 TIG Rod (ER4643) | AWS A5.10 / ISO 18273 | 1.6, 2.0, 2.4, 3.2, 4.0 | 500, 1000 | Clean / brushed |
| Formulier | Specificatie | Diameter (mm) | Spool Size | Oppervlak |
|---|---|---|---|---|
| 4643 MIG Wire (ER4643) | AWS A5.10 / ISO 18273 | 0.8, 1.0, 1.2, 1.6, 2.4 | 5 kg (D200), 15 kg (D300), 20 kg (D350) | Clean / layer wound |
| Formulier | Temper | Diameter (mm) | Lengte (mm) |
|---|---|---|---|
| 4643 Bare Rod / Bar | F, O | 3 – 50 | 1000 – 3000 |
4643 is a specialized filler alloy and is not commonly stocked in structural forms such as sheet, plate, or tube. If your project requires 4643 in non-standard forms or custom dimensions, contact our team to confirm feasibility and lead time.
| Standaardsysteem | Benaming |
|---|---|
| UNS | A94643 |
| AA / Aluminum Association | 4643 |
| AWS (Welding Filler) | ER4643 |
| ISO (Welding Consumable) | ISO 18273 — AlSi4Mg0.2 |
| EN (Welding Consumable) | EN ISO 18273 — AlSi4Mg |
Algemeen geldende normen:
Typical composition limits (per Aluminum Association registration and AWS A5.10, weight %):
| Element | Min % | Max % |
|---|---|---|
| Silicium (Si) | 3.6 | 4.6 |
| IJzer (Fe) | — | 0.8 |
| Koper (Cu) | — | 0.10 |
| Mangaan (Mn) | — | 0.05 |
| Magnesium (Mg) | 0.10 | 0.30 |
| Zink (Zn) | — | 0.10 |
| Anderen, elk | — | 0.05 |
| Overige, totaal | — | 0.15 |
| Aluminium (Al) | Rest | |
4643 is a welding filler alloy, so mechanical properties are reported for the weld deposit rather than for a wrought product form. Properties depend heavily on the base metal, joint design, welding parameters, and post-weld heat treatment condition.
| Eigendom | Typische waarde | Toestand |
|---|---|---|
| Treksterkte (Ultieme) | 280 – 360 MPa | Post-weld aged weld deposit on 6xxx base metal |
| Rek bij breuk | 2.2 – 18% | Range reflects as-welded (higher) vs. post-weld aged (lower) conditions |
Notes: In the as-welded condition, 4643 weld deposits typically exhibit lower tensile strength but higher elongation. After post-weld solution heat treatment and artificial aging (T6 condition), the Mg addition enables the weld deposit to age-harden, achieving significantly higher tensile strength — the primary advantage of 4643 over 4043. Actual properties vary with base metal composition, joint geometry, and welding parameters.
4643 was developed specifically to address the limitations of 4043 in structural welding applications. The table below summarizes the critical differences:
| Functie | 4043 (ER4043) | 4643 (ER4643) |
|---|---|---|
| Composition | Al – 5% Si | Al – 4% Si – 0.2% Mg |
| Si Content | 4.5 – 6.0% | 3.6 – 4.6% |
| Mg Content | None specified | 0.10 – 0.30% |
| Weld Deposit Heat-Treatable | No | Yes (post-weld aging) |
| Post-Weld Aged Strength | No improvement (remains ~165 MPa) | Significantly improved (280 – 360 MPa) |
| Crack Resistance | Uitstekend | Uitstekend |
| Fluïditeit | High (higher Si content) | Hoog |
| Primary Use | General 6xxx welding, non-structural | Structural 6xxx welding requiring post-weld aging |
Choose 4043 for general-purpose welding where post-weld heat treatment is not required. Choose 4643 when the welded assembly will be solution heat treated and aged, and the weld joint must achieve higher strength to match the T6 properties of the 6xxx base metal.
4643 is recommended for welding 6xxx series aluminum alloys, including:
4643 can also be used for welding dissimilar 6xxx / 5xxx joints where the 5xxx component has low Mg content. For high-Mg 5xxx base metals (e.g., 5083, 5086), use 5356 or 5183 filler instead to avoid Mg-Si embrittlement.
To achieve the full strength advantage of 4643, the welded assembly should be solution heat treated and artificially aged (T6 condition) after welding. This activates the Mg addition in the weld deposit, allowing it to age-harden alongside the 6xxx base metal. Without post-weld heat treatment, 4643 weld deposits perform similarly to 4043.
The defining characteristic of 4643 is its ability to age-harden in the weld deposit. The 0.10-0.30% magnesium addition forms Mg₂Si precipitates during artificial aging, significantly increasing weld joint strength. This makes 4643 the preferred filler for structural 6xxx welds that will be post-weld heat treated.
Like 4043, 4643 offers excellent resistance to weld cracking, particularly on 6xxx series base metals. The silicon content lowers the melting point and improves fluidity, reducing the risk of solidification cracking in the weld bead.
4643 weld deposits provide good corrosion resistance in atmospheric and mild industrial environments. The silicon-rich weld metal is generally compatible with the corrosion behavior of 6xxx base metals, making it suitable for outdoor and marine-adjacent applications.
4643 produces a weld bead that anodizes to a color reasonably close to 6xxx base metal, though the silicon content can cause a slightly gray tone. For applications requiring a perfect color match after anodizing, consider 5356 filler for 5xxx base metals or consult our team for guidance.
4643 is used wherever structural welding of 6xxx series aluminum requires post-weld heat treatment for maximum joint strength:
4643 is a welding filler alloy, so processing notes focus on welding parameters and post-weld treatment rather than machining or forming:
De kwaliteitscontrole bij Linsy omvat het hele proces, van de selectie van grondstoffen tot de inspectie van het eindproduct. Elke bestelling wordt geleverd met een MTC (Material Test Certificate) dat na de productie door Linsy Aluminum wordt afgegeven en waarin de resultaten van de chemische samenstelling en de mechanische eigenschappen van de betreffende partij zijn opgenomen.
Voor klanten die verificatie door een derde partij nodig hebben, zijn SGS-testrapporten op verzoek verkrijgbaar tegen extra testkosten. Beschikbare SGS-rapporten zijn onder meer:
Linsy Aluminum is a Shenzhen-based aluminum factory with more than 20 years of industry experience, supplying 4643 welding filler and other 1000-8000 series alloys to customers across general engineering, automotive, marine, shipbuilding, construction, manufacturing, and power electronics.
For your 4643 sourcing, this means:
4643 is used as a welding filler metal for joining 6xxx series aluminum alloys (6061, 6063, 6082, 6A02). It is specifically designed for structural welds that will be post-weld heat treated, where the weld deposit must achieve higher strength through age hardening to match the T6 properties of the base metal.
4043 is an Al-Si filler (no magnesium) whose weld deposit cannot be age-hardened. 4643 adds 0.10-0.30% magnesium, which enables the weld deposit to respond to post-weld solution heat treatment and artificial aging. After aging, 4643 weld joints achieve significantly higher tensile strength than 4043 weld joints. For welds that will not be post-weld heat treated, 4043 and 4643 perform similarly.
Yes. The magnesium addition in 4643 forms Mg₂Si precipitates during artificial aging, which strengthens the weld deposit. This is the key advantage of 4643 over 4043. To activate this strengthening, the welded assembly must be solution heat treated and artificially aged (T6 condition) after welding.
4643 is recommended for welding 6xxx series aluminum alloys, including 6061, 6063, 6082, and 6A02. It can also be used for some dissimilar 6xxx/5xxx joints where the 5xxx component has low Mg content. For high-Mg 5xxx base metals (5083, 5086), use 5356 or 5183 filler to avoid Mg-Si embrittlement.
4643 is used with both GTAW (TIG) and GMAW (MIG) processes. For TIG, use 4643 cut-length rods in 1.6-4.0 mm diameter with AC current and pure argon shielding. For MIG, use 4643 spooled wire in 0.8-2.4 mm diameter with push technique and argon or Ar/He shielding gas.
TIG filler rods are available in 1.6, 2.0, 2.4, 3.2, and 4.0 mm diameters in 500 mm or 1000 mm cut lengths. MIG welding wire is available in 0.8, 1.0, 1.2, 1.6, and 2.4 mm diameters on 5 kg, 15 kg, or 20 kg spools. Custom diameters can be arranged on request.
4643 can be used for aluminum brazing applications due to its silicon content, which lowers the melting point and improves fluidity. However, for dedicated brazing applications, specialized brazing filler metals (such as 4343 or 4045) are typically more appropriate. Consult our team for guidance on your specific brazing application.
4643 welding filler is classified as ER4643 under AWS A5.10/A5.10M (Specification for bare aluminum and aluminum-alloy welding electrodes and rods). The ISO equivalent is ISO 18273 (AlSi4Mg0.2). The Aluminum Association designation is 4643, and the UNS number is A94643.
For non-stock diameters or custom specifications, typical lead time is 10-60 days depending on alloy, dimensions, processing requirements, and order complexity. In-stock standard specifications can ship faster — contact our team for a specific quote.
Linsy supports low-MOQ custom production for non-stock 4643 items. MOQ varies by diameter, spool size, and processing scope; please share your requirements and we will confirm feasibility.
Every order ships with an MTC (Material Test Certificate) issued by Linsy Aluminum after production. Optional SGS third-party test reports are available on request at an additional testing cost.
Yes, samples can be arranged for most standard and custom specifications. Sample cost and lead time depend on diameter and processing requirements.
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