319.0 Aluminum
An Al-Si-Cu casting alloy, for engine blocks and cylinder heads
Typical values for the temper in the title
319 is a casting alloy with about 6% silicon and about 3.5% copper. The silicon gives good castability and the copper gives strength, good machining, and properties that hold at moderate temperature. As sand cast, its tensile strength is about 186 MPa.
It is a common workhorse for sand and permanent-mold casting: engine blocks, cylinder heads, gearbox housings and general parts. It is more tolerant of impurities than A356, so it is also cast from recycled material.
Mechanical and physical properties
| Property | Value | Note |
|---|---|---|
| Tensile strength Rm | 186 MPa | |
| Yield strength Rp0.2 | 124 MPa | |
| Elongation A | 2% | |
| Hardness | 70 HB | |
| Modulus of elasticity E | 71 GPa | |
| Density ρ | 2.79 g/cm³ | |
| Machinability | 70% | relative rating in the site database |
Chemical composition (wt %)
| Element | Range | Role |
|---|---|---|
| Si silicon | 5.5–6.5 | castability |
| Cu copper | 3.0–4.0 | strength and machinability |
| Fe iron | max 1.0 | |
| Zn zinc | max 1.0 | |
| Mn manganese | max 0.50 | |
| Ni nickel | max 0.35 | |
| Ti titanium | max 0.25 | |
| Mg magnesium | max 0.10 | |
| Al aluminum | balance |
Common tempers
319 is used both as cast and after heat treatment for higher strength.
| Temper | Properties | When to choose it |
|---|---|---|
| F | Rm ≈ 186 MPa (sand cast) | as cast |
| T5 | slightly higher strength | aging only |
| T6 | higher strength | solution treated and aged |
Applications
- Engine blocks
- Cylinder heads
- Gearbox housings
- Pump and compressor housings
- General castings
Fabrication
Casting
Suited to sand and permanent-mold casting, and tolerant of recycled material.
Machining
Machines well thanks to the copper.
Welding and corrosion
Welding is possible for repairs, usually with 4043 filler. The copper lowers corrosion resistance.
Compared with similar materials
| Material | Rm / Rp0.2 | Welding | When it is the better choice |
|---|---|---|---|
| A356.0-T6 | 262 / 186 MPa | Good — ER4043 | more ductile and stronger in T6, and more corrosion resistant · material page |
| A380.0 | 317 / 159 MPa | Not possible (HPDC) | for high-pressure die casting · material page |
| 242.0 | 220 / 180 MPa | Not possible | for high temperature · material page |
Common mistakes
Choosing 319 for a part that needs high ductility
Its ductility is low. For a safety part, A356.
Leaving a casting unprotected in a humid environment
The copper lowers corrosion resistance.
Designing to T6 strength when the casting is F
Strength depends on heat treatment. The temper on the drawing is binding.
Equivalents, standards and supply
| ASTM | 319.0 (ASTM B26, B108) |
|---|---|
| EN | EN AC-45000 (AlSi6Cu4) |
| JIS | AC2B |
| Standards | ASTM B26 / EN 1706 |
| Forms | gravity casting / HPDC |
| Producers | Alcoa · Nemak · Intermet · Kaiser |
Learn more
Values are typical and for comparison only. For design, rely on the standard and on the mill certificate. Sources: Aluminum Association (composition), ASM and MatWeb data sheets, and the METAL HUB materials database.
Updated: October 31, 2026