319 (AlSi6Cu3)
The most produced alloy in North America for automotive engine blocks and cylinder heads. Excellent machinability and elevated-temperature strength.
The 319 family (AlSi6Cu3) is the most widely used alloy in North America for engine blocks and cylinder heads. The combination of silicon (~6%) and copper (~3.5%) provides excellent fluidity, good elevated-temperature strength, and outstanding machinability. The B319 variant includes magnesium (0.10–0.50%) for improved T6 heat treatment response. Can be produced from recycled wheel aluminum by adjusting copper content.
International Nomenclature
| Standard | Designation |
|---|---|
| AA (USA) | 319.0 / B319.0 |
| EN (Europa) | EN AC-45000 · AlSi6Cu4 |
| DIN (Alemania) | G-AlSi6Cu4 / 3.2151 |
| JIS (Japón) | AC2B |
Chemical Composition
| Element | Symbol | Percentage |
|---|---|---|
| Aluminum | Al | Balance |
| Silicon | Si | 5.5–6.5% |
| Copper | Cu | 3.0–4.0% |
| Iron | Fe | ≤1.00% (319) · ≤0.60% (B319) |
| Magnesium | Mg | ≤0.10% (319) · 0.10–0.50% (B319) |
| Manganese | Mn | ≤0.50% |
| Zinc | Zn | ≤1.00% |
| Nickel | Ni | ≤0.35% |
| Titanium | Ti | ≤0.25% |
Physical Properties
| Property | Value |
|---|---|
| Density | 2.79 g/cm³ |
| Melting Range | 520–600 °C |
| Thermal Conductivity | 109 W/m·K |
| Electrical Conductivity | ~27% IACS |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength (UTS) | 235–250 MPa (T6 (B319)) |
| Yield Strength | 165–200 MPa (T6) |
| Elongation | 1.5–3.0% |
| Hardness | ~85 HB |
| Elevated Temp. Strength | Retiene resistencia a 200°C+ |
Key Characteristics
- The most produced casting alloy in North America for engine blocks
- Copper provides excellent strength retention at elevated temperatures
- Outstanding machinability thanks to the Al₂Cu phase
- B319 with Mg (0.10–0.50%) for improved T6 properties
- Manufacturable from recycled aluminum wheel base by adjusting Cu content
- Excellent for permanent mold and sand casting with good pressure tightness
Industries & Applications
Automotive — Powertrain
Engine blocks, cylinder heads, intake manifolds, oil pans
Automotive — Transmission
Transmission housings, transfer cases, valve bodies
Industrial
Compressors, pumps, hydraulic manifolds, valve bodies
Special Notes
319/B319 is the standard GM and Ford alloy for engine blocks and cylinder heads. Its copper content gives it elevated-temperature strength retention (critical for engine components operating at 150–250°C). The B319 variant adds Mg to improve T6 heat treatment response. We can manufacture this alloy starting from recycled wheel aluminum (base ~AlSi7) by adjusting silicon composition and adding copper.
Frequently Asked Questions
What is the 319 (AlSi6Cu3) alloy and what is it used for?
The 319 (AlSi6Cu3) is an Al-Si-Cu casting alloy and the most produced casting alloy in North America for engine blocks and cylinder heads. It is the standard GM and Ford alloy for these powertrain components. It is also used in intake manifolds, oil pans, transmission housings, and industrial applications such as compressors, pumps, and valve bodies.
What is the chemical composition of 319 and what does each element contribute?
319 contains approximately 5.5–6.5% silicon and 3.0–4.0% copper, with the balance being aluminum. Silicon provides excellent fluidity and castability, while copper provides mechanical strength and, especially, strength retention at elevated temperatures. The B319 variant includes magnesium (0.10–0.50%) and a tighter iron limit (≤0.60% versus ≤1.00% for 319).
Is 319 heat-treatable and what strength does it reach?
Yes, 319 responds to heat treatment, and the magnesium-bearing B319 variant significantly improves the T6 response. In the T6 condition, B319 reaches a tensile strength (UTS) of 235–250 MPa, a yield strength of 165–200 MPa, an elongation of 1.5–3.0%, and a hardness of about 85 HB. The magnesium in B319 is key to optimizing these T6 properties.
Why does 319 retain its strength at high temperature?
The copper content (3.0–4.0%) gives 319 excellent strength retention at elevated temperature, retaining strength at 200 °C and above. This is critical for engine components operating in the 150–250 °C range, such as blocks and cylinder heads. This is why it is the standard choice for powertrain parts subjected to continuous heat.
Which casting processes is 319 suited for?
319 is excellent for permanent mold and sand casting, offering good pressure tightness, which makes it ideal for parts that must contain fluids such as engine blocks and transmission housings. Its high silicon content (~6%) gives it excellent fluidity for filling complex geometries.
Why does 319 have such good machinability?
319 offers outstanding machinability thanks to the Al₂Cu phase formed by the copper, which promotes chip breaking and a good surface finish. This is one of the reasons it is preferred for components requiring extensive precision machining, such as cylinder heads, valve bodies, and transmission valve bodies.
Can you manufacture 319 from recycled wheel aluminum (rin)?
Yes. At Transformación Puebla we can manufacture 319 starting from recycled wheel aluminum, whose base is approximately AlSi7, by adjusting the silicon content and adding copper to reach the target composition (5.5–6.5% Si and 3.0–4.0% Cu). We can also produce it from a primary aluminum base.
Need 319 (AlSi6Cu3)?
We manufacture this alloy in ingots, donuts, and bars to your exact specifications.