Aluminum 319 · temper
Aluminum 319-T6
Properties of the T6 condition, compared with the other 319 tempers.
Highest strength condition; choose for loaded structural or pressure castings where full heat-treat cost and some distortion are acceptable.
What is 319-T6?
319-T6 is 319 in the T6 temper — highest strength condition; choose for loaded structural or pressure castings where full heat-treat cost and some distortion are acceptable. 319-T6 has a yield strength of 165 MPa (23.9 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 59% of aluminum grades. Elongation at break is 2% and the elastic modulus is 74 GPa (10.7 Msi). 319-T6 has a density of 2.79 g/cm³ (0.101 lb/in³), heavier than 77% of aluminum grades. It melts at 521°C (970 °F).
Advantages
- Easy to machine — 75/100, better than 86% of aluminum grades
Limitations
- Limited formability — 5/100, worse than 94% of aluminum grades
- Poor heat conductor — 109 W/m·K (63 BTU/hr·ft·°F), worse than 90% of aluminum grades
- Low electrical conductivity — 26 % IACS, worse than 90% of aluminum grades
- Hard to polish — 40/100, worse than 90% of aluminum grades
- Limited ductility — 2%, worse than 87% of aluminum grades
319-T6 properties
Typical room-temperature values for 319-T6 — 11 properties are specific to this condition; the rest are grade-level values shared by every 319 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
319-T6 has a density of 2.79 g/cm³ (0.101 lb/in³), heavier than 77% of aluminum grades. It melts at 521°C (970 °F).
Mechanical12
319-T6 has a yield strength of 165 MPa (23.9 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 59% of aluminum grades. Elongation at break is 2% and the elastic modulus is 74 GPa (10.7 Msi).
Thermal6
319-T6 is rated for continuous service to 150°C (302 °F). It conducts heat at 109 W/m·K (63 BTU/hr·ft·°F), worse than 90% of aluminum grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
319-T6 conducts electricity at 26 % IACS, worse than 90% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), worse than 85% of aluminum grades.
Sustainability4
Producing a kilogram of 319-T6 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 75%.
Manufacturability8
319-T6's machinability is very good (75/100, better than 86% of aluminum grades); weldability good (55/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 319 tempers and conditions
319 is also supplied in 2 other conditions. The full side-by-side table is on the 319 overview.
- T5Cheap ageing-only treatment: raises yield strength and improves dimensional stability with no solution-treatment distortion, at the cost of ductility.179 MPa yield · 80 HB
- T6Highest strength condition; choose for loaded structural or pressure castings where full heat-treat cost and some distortion are acceptable.165 MPa yield · 80 HB
- T7Overaged for maximum dimensional and thermal stability (e.g. cylinder heads, fixtures) — gives up some strength versus T6 in exchange for stability and ductility.150 MPa yield · 75 HB
Working with 319-T6
Is 319 easy to machine?
One of the better-machining cast aluminium alloys — Cu-rich phases break chips well; use carbide or PCD tooling because of the hard primary/eutectic Si, and expect tool wear higher than in 6061.
Can 319 be welded?
Weldable with 4145 (or 4047) filler; the 3–4 % Cu increases hot-cracking sensitivity, so preheat, keep heat input low, and re-heat-treat after welding on T5/T6 parts.
Can 319 be formed, bent or molded?
Casting alloy only — excellent fluidity and low hot-tear tendency for sand, permanent-mould and low-pressure casting of thin, complex sections; grain-refine and Sr/Na modify the eutectic for best properties.
What surface finishes work on 319?
Painting, powder coating or chromate/chrome-free conversion coating are preferred; decorative anodizing gives a dark, blotchy film due to high Si + Cu, and impregnation is often needed to seal porosity before plating.
319 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 | 5.5 – 6.5 | 6 |
| Cu | 3 – 4 | 3.5 |
| Fe319.0 max 1.0 %; A319.0/B319.0 also 1.0 %, die-cast variants higher | ≤ 1 | 0.6 |
| Mn | ≤ 0.5 | 0.25 |
| MgB319.0 raises Mg to 0.10–0.50 % for higher strength | ≤ 0.1 | 0.05 |
| Ni | ≤ 0.35 | — |
| ZnA319.0 allows up to 3.0 % Zn | ≤ 1 | 0.3 |
| Ti | ≤ 0.25 | 0.12 |
| Others (each)total others 0.15 % max | ≤ 0.05 | — |
| Al | balance | — |
319-T6 — frequently asked
What is 319-T6 used for?
319-T6 is typically used for engine crankcases, manifolds and cylinder heads. In short: cu-bearing sand cast.
What is the yield strength of 319-T6?
319-T6 has a typical yield strength of 165 MPa (23.9 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 59% of aluminum grades. Strength varies by condition: see the 3 listed tempers.
Is 319-T6 easy to machine?
Yes — machinability is rated very good (75/100, better than 86% of aluminum grades). One of the better-machining cast aluminium alloys — Cu-rich phases break chips well; use carbide or PCD tooling because of the hard primary/eutectic Si, and expect tool wear higher than in 6061.
Can 319-T6 be welded?
Yes — weldability is rated good (55/100). Weldable with 4145 (or 4047) filler; the 3–4 % Cu increases hot-cracking sensitivity, so preheat, keep heat input low, and re-heat-treat after welding on T5/T6 parts.
What surface finishes work on 319-T6?
Painting, powder coating or chromate/chrome-free conversion coating are preferred; decorative anodizing gives a dark, blotchy film due to high Si + Cu, and impregnation is often needed to seal porosity before plating.
Can 319-T6 be formed, bent or molded?
Casting alloy only — excellent fluidity and low hot-tear tendency for sand, permanent-mould and low-pressure casting of thin, complex sections; grain-refine and Sr/Na modify the eutectic for best properties.
What is the maximum service temperature of 319-T6?
319-T6 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.
Can FabDigit make parts in 319-T6?
Yes — 319-T6 is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot (Pink Sheets) — The Aluminum Association (2018)
- ASTM B26/B26M — Aluminum-Alloy Sand Castings — ASTM International (2018)
- ASTM B108/B108M — Aluminum-Alloy Permanent Mold Castings — ASTM International (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
- GB/T 1173 (comparable ZL107) — SAC (2013)
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.