Aluminum 443-T6
Temper
AA 443 · UNS A04430 · EN AlSi5 · BS LM18 · also S5C
T6 = solution heat treated and artificially aged
Nominal T6 on 443: with essentially no Mg or Cu the alloy is not precipitation hardenable, so solution treating and ageing only spheroidises the eutectic silicon — strength rises marginally over F and the temper is rarely specified commercially.
Values for the T6 condition
Other 443 tempers and conditions
443 is listed in 6 conditions; see the grade overview at 443.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
B443.0-F | Choose when maximum corrosion resistance and anodic/chemical-finish quality are needed; copper held to 0.15 % max. | 41 | 117 | 6 | 35 HB | 39 % IACS |
As fabricated | Standard supply condition for sand castings; alloy is not heat-treatable, so F covers virtually all commercial 443 parts. | 55 | 130 | 8 | 40 HB | 37 % IACS |
Cooled from hot working and artificially aged | Nominal T5 on 443: ageing straight from the casting heat gives no precipitation strengthening in this Mg- and Cu-free Al-5Si alloy, so it acts mainly as a dimensional stress-relief and properties stay close to as-cast F. | 60 | 135 | 7 | 42 HB | 38 % IACS |
F | Pick for permanent-mold parts needing somewhat higher strength and ductility than sand casting from faster solidification. | 62 | 159 | 10 | 45 HB | 37 % IACS |
T6This page Solution heat treated and artificially aged | Nominal T6 on 443: with essentially no Mg or Cu the alloy is not precipitation hardenable, so solution treating and ageing only spheroidises the eutectic silicon — strength rises marginally over F and the temper is rarely specified commercially. | 70 | 150 | 6 | 45 HB | 38 % IACS |
C443.0-F | Die-casting version of the alloy: highest strength and hardness of the 443 family, chosen for thin-wall pressure die castings needing ductility and corrosion resistance. | 110 | 228 | 9 | 65 HB | 37 % IACS |
What is 443-T6?
443-T6 is 443 in the T6 temper — nominal T6 on 443: with essentially no Mg or Cu the alloy is not precipitation hardenable, so solution treating and ageing only spheroidises the eutectic silicon — strength rises marginally over F and the temper is rarely specified commercially. 443-T6 has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 150 MPa (21.8 ksi) — weaker than 92% of aluminum grades. Elongation at break is 6% and the elastic modulus is 71 GPa (10.3 Msi). 443-T6 has a density of 2.69 g/cm³ (0.0972 lb/in³), lighter than 67% of aluminum grades. It melts at 577°C (1,071 °F).
Advantages
- High service temperature — 200°C (392 °F), better than 90% of aluminum grades
- Readily welded — 85/100, better than 79% of aluminum grades
Limitations
- Low strength — 70 MPa (10.2 ksi), worse than 92% of aluminum grades
- Low fracture toughness — 17 MPa·√m (15.5 ksi·√in), worse than 83% of aluminum grades
- Hard to polish — 45/100, worse than 76% of aluminum grades
443-T6 properties
Typical room-temperature values for 443-T6; 19 are specific to this condition. Other listed values are 443 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
443-T6 has a density of 2.69 g/cm³ (0.0972 lb/in³), lighter than 67% of aluminum grades. It melts at 577°C (1,071 °F).
Mechanical11
443-T6 has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 150 MPa (21.8 ksi) — weaker than 92% of aluminum grades. Elongation at break is 6% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
443-T6 is rated for continuous service to 200°C (392 °F). It conducts heat at 146 W/m·K (84.4 BTU/hr·ft·°F), better than 55% of aluminum grades. Thermal expansion is 22.1 µm/m·K (12.3 µin/in·°F).
Electrical3
443-T6 conducts electricity at 38 % IACS, better than 61% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), better than 57% of aluminum grades.
Sustainability4
Producing a kilogram of 443-T6 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 70%.
Manufacturability6
443-T6's machinability is fair (50/100, worse than 65% of aluminum grades); weldability excellent (85/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 443-T6
Is 443 easy to machine?
Soft and gummy — use sharp polished-flute carbide, high speed, generous rake and flood lubricant to avoid built-up edge and torn surfaces.
Can 443 be welded?
Very good weldability by GTAW/GMAW with 4043 or 4047 filler; no post-weld heat treatment can restore strength since the alloy is non-heat-treatable.
Can 443 be formed, bent or molded?
Excellent fluidity and low hot-tear tendency for sand, permanent-mold and (as C443.0) pressure die casting; not a wrought alloy — no cold forming.
What surface finishes work on 443?
Takes chemical conversion coating and paint well; hard anodize is protective but decorative clear anodize turns grey due to silicon; polishing limited by eutectic Si.
443 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 |
|---|---|---|
| Si443.0 per ASTM B26/B108 | 4.5 – 6 | 5.25 |
| Fe2.0 max in C443.0 die-casting variant | ≤ 0.8 | — |
| Cu0.15 max in B443.0; 0.30 max in A443.0 | ≤ 0.6 | — |
| Mn0.35 max in C443.0 | ≤ 0.5 | — |
| Mgkept low — alloy is intentionally non-heat-treatable | ≤ 0.05 | — |
| Zn | ≤ 0.5 | — |
| Ti | ≤ 0.25 | — |
| NiC443.0 only | ≤ 0.5 | — |
| Others (each)total 0.15 max | ≤ 0.05 | — |
| Al | balance | — |
443-T6 — frequently asked
What is 443-T6 used for?
443-T6 is typically used for decorative castings, hardware and fittings, thin-wall complex sand castings, marine fittings exposed to seawater, pressure-tight housings and covers and die-cast enclosures (C443.0). In short: low-strength cast Al-Si.
What is the yield strength of 443-T6?
443-T6 has a typical yield strength of 70 MPa (10.2 ksi) and a tensile strength of 150 MPa (21.8 ksi) — weaker than 92% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is 443-T6 easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 65% of aluminum grades). Soft and gummy — use sharp polished-flute carbide, high speed, generous rake and flood lubricant to avoid built-up edge and torn surfaces.
Can 443-T6 be welded?
Yes — weldability is rated excellent (85/100). Very good weldability by GTAW/GMAW with 4043 or 4047 filler; no post-weld heat treatment can restore strength since the alloy is non-heat-treatable.
What surface finishes work on 443-T6?
Takes chemical conversion coating and paint well; hard anodize is protective but decorative clear anodize turns grey due to silicon; polishing limited by eutectic Si.
Can 443-T6 be formed, bent or molded?
Excellent fluidity and low hot-tear tendency for sand, permanent-mold and (as C443.0) pressure die casting; not a wrought alloy — no cold forming.
What is the maximum service temperature of 443-T6?
443-T6 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 443-T6?
Yes — 443-T6 is available for CNC machining; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B26/B26M — Aluminum-Alloy Sand Castings — ASTM International (2018)
- ASTM B108/B108M — Aluminum-Alloy Permanent Mold Castings — ASTM International (2019)
- ASTM B85/B85M — Aluminum-Alloy Die Castings — ASTM International (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Aluminum Association Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot (Pink Sheets) — The Aluminum Association (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.