Aluminum 4643
AA 4643 · UNS A94643 · EN AW-4643, AW 4643 · JIS A4643
4643 (EN AW-4643, AlSi1MgMn) is an Al–Si–Mg welding filler alloy with about 4 % Si and 0.10–0.30 % Mg — effectively 4043 with enough magnesium to respond to post-weld heat treatment.
4643 tempers and conditions
4643 is supplied in 4 conditions, soft to hard.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Soft annealed wire/rod, chosen when maximum ductility for coiling or hand feeding is required. | 50 | 130 | 22 | 35 HB | 42 % IACS |
As fabricated | Standard supply condition for ER4643 spooled MIG wire and R4643 TIG rod. | 70 | 165 | 15 | 45 HB | 41 % IACS |
As-welded deposit | Typical all-weld-metal properties when the joint is left in the as-welded condition. | 75 | 170 | 12 | 48 HB | 40 % IACS |
weld deposit solution heat treated and artificially aged after welding | Choose when the whole weldment is post-weld solution treated and aged — the reason 4643 exists instead of 4043. | 195 | 270 | 8 | 80 HB | 39 % IACS |
What is 4643?
4643 (EN AW-4643, AlSi1MgMn) is an Al–Si–Mg welding filler alloy with about 4 % Si and 0.10–0.30 % Mg — effectively 4043 with enough magnesium to respond to post-weld heat treatment. It is used for TIG and MIG welding of heat-treatable 6000-series alloys such as 6061, 6063 and 6082, where a post-weld solution treatment plus artificial ageing raises joint strength well above a 4043 deposit. It is supplied only as wire and rod, not as plate or extrusion, its strength advantage is limited if the weldment is left as-welded, and the silicon content makes anodised deposits darker than the base metal. Choose 4043 or 5356 when no post-weld heat treatment is planned. 4643 has a density of 2.69 g/cm³ (0.0972 lb/in³), lighter than 67% of aluminum grades. It melts at 574°C (1,065 °F). 4643 has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 165 MPa (23.9 ksi) — weaker than 92% of aluminum grades. Elongation at break is 15% and the elastic modulus is 69 GPa (10 Msi).
What is 4643 used for?
- Filler wire for 6061 weldments
- 6063 extrusion joints
- 6082 structural welds
- Weldments given a post-weld solution and ageing cycle
- Repair welds on heat-treated 6000-series extrusions and forgings
- Small remelt cast shapes
Advantages
- Readily welded — 96/100, better than 100% of aluminum grades
- Forms and bends easily — 72/100, better than 85% of aluminum grades
- Ductile — tolerates forming and impact — 15%, better than 82% of aluminum grades
- High electrical conductivity — 41 % IACS, better than 78% of aluminum grades
- Conducts heat well — 160 W/m·K (92.4 BTU/hr·ft·°F), better than 76% of aluminum grades
Limitations
- Low strength — 70 MPa (10.2 ksi), worse than 92% of aluminum grades
- Difficult to machine — 40/100, worse than 81% of aluminum grades
- Hard to polish — 45/100, worse than 76% of aluminum grades
4643 properties
Typical room-temperature values; bars are the position among aluminum grades.
Physical3
4643 has a density of 2.69 g/cm³ (0.0972 lb/in³), lighter than 67% of aluminum grades. It melts at 574°C (1,065 °F).
Mechanical10
4643 has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 165 MPa (23.9 ksi) — weaker than 92% of aluminum grades. Elongation at break is 15% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
4643 is rated for continuous service to 150°C (302 °F). It conducts heat at 160 W/m·K (92.4 BTU/hr·ft·°F), better than 76% of aluminum grades. Thermal expansion is 22 µm/m·K (12.2 µin/in·°F).
Electrical3
4643 conducts electricity at 41 % IACS, better than 78% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), better than 67% of aluminum grades.
Sustainability4
Producing a kilogram of 4643 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 20%.
Manufacturability8
4643's machinability is fair (40/100, worse than 81% of aluminum grades); weldability excellent (96/100); formability very good (72/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the aluminum family
Yield strength against density for every aluminum grade FabDigit runs. 4643 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 4643
Is 4643 easy to machine?
Rarely machined; deposits are soft and gummy — use sharp polished-flute carbide, high speed, low feed and generous lubrication to avoid built-up edge.
Can 4643 be welded?
Purpose-made GMAW/GTAW filler for 6000-series alloys; keep interpass temperature low, clean oxide thoroughly, and specify 4643 only when a post-weld solution + age cycle is planned (otherwise 4043 or 5356 is cheaper).
Can 4643 be formed, bent or molded?
Supplied as drawn wire/rod; good drawability in O temper, and the alloy is fluid enough to cast small remelt shapes if needed.
Manufacturability
The process limits FabDigit applies to 4643. Every 4643 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better40 / 100 |
|---|---|
| ISO material group | N.1 |
| Cutting speed (rough / finish) | 350 / 420 m/min |
| Minimum wall | 0.5 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 8× diameter |
| Best surface (machined / polished) | Ra 0.8 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Excellent72 / 100 |
|---|---|
| Weldability | Excellent96 / 100 |
4643 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Si | 3.6 – 4.6 | 4.1 |
| Mgaddition vs 4043 that enables post-weld T6 strengthening | 0.1 – 0.3 | 0.2 |
| Fe | ≤ 0.8 | |
| Cu | ≤ 0.1 | |
| Mn | ≤ 0.05 | |
| Zn | ≤ 0.1 | |
| Ti | ≤ 0.15 | |
| Bemax, where restricted by AWS A5.10 | ≤ 8×10⁻⁴ | |
| Others (each)each | ≤ 0.05 | |
| Others (total)total | ≤ 0.15 | |
| Al | balance |
What surface finishes work on 4643?
Anodizes fair — film is lighter than 4043 and closer to 6061 base metal, but weld beads still shade grey; chemical conversion coating or paint gives the most uniform appearance.
Surface treatments FabDigit runs on aluminum parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Conversion Coating
PVD Coating
Equivalent designations
Standards and trade names that resolve to Aluminum 4643 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- A94643
- Aluminum Association
- AA4643
- EN / DIN / Werkstoff-Nr.
- AW-4643AW 4643AlSi1MgMn
- JIS
- A4643
How much does 4643 cost?
4643 is a standard-cost aluminum ($$), cheaper than about 62% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
4643 — frequently asked
What is 4643 used for?
4643 is typically used for filler wire for 6061 weldments, 6063 extrusion joints, 6082 structural welds, weldments given a post-weld solution and ageing cycle, repair welds on heat-treated 6000-series extrusions and forgings and small remelt cast shapes. In short: heat-treatable filler wire.
What is the yield strength of 4643?
4643 has a typical yield strength of 70 MPa (10.2 ksi) and a tensile strength of 165 MPa (23.9 ksi) — weaker than 92% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is 4643 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 81% of aluminum grades). Rarely machined; deposits are soft and gummy — use sharp polished-flute carbide, high speed, low feed and generous lubrication to avoid built-up edge.
Can 4643 be welded?
Yes — weldability is rated excellent (96/100). Purpose-made GMAW/GTAW filler for 6000-series alloys; keep interpass temperature low, clean oxide thoroughly, and specify 4643 only when a post-weld solution + age cycle is planned (otherwise 4043 or 5356 is cheaper).
What surface finishes work on 4643?
Anodizes fair — film is lighter than 4043 and closer to 6061 base metal, but weld beads still shade grey; chemical conversion coating or paint gives the most uniform appearance.
Can 4643 be formed, bent or molded?
Supplied as drawn wire/rod; good drawability in O temper, and the alloy is fluid enough to cast small remelt shapes if needed.
What is the maximum service temperature of 4643?
4643 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 4643 cost?
4643 is a standard-cost aluminum ($$), cheaper than about 62% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in 4643?
Yes — 4643 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- AWS A5.10/A5.10M — Specification for Bare Aluminum and Aluminum-Alloy Welding Electrodes and Rods — AWS (2021)
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- EN ISO 18273 — Welding consumables: wire and rods for fusion welding of aluminium and aluminium alloys — CEN/ISO (2015)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (aluminium filler metal selection) — ASM International (1993)
- Aluminium filler metal selection guides (ER4643 / R4643) — Welding consumable producers (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.