Aluminum 713 is most commonly searched as a casting-grade aluminum alloy, often written as
Aluminum 713, al alloy 713, Al 713, 713.0 aluminum or A713.0 depending on the purchasing document, foundry
standard or regional naming practice. In engineering use, it is generally associated with high-strength
aluminum castings where a zinc-magnesium-copper strengthening system is used to achieve better mechanical
performance than many conventional aluminum-silicon casting alloys.
This guide is written for engineers, sourcing teams, casting buyers and machinists who need to understand
whether Al 713 is suitable for structural castings, housings, brackets, aerospace-related parts, high-load
industrial components or precision-machined cast blanks.
What Is 713 Aluminum?
713 aluminum is a heat-treatable aluminum casting alloy. Unlike common Al-Si casting alloys such as 356 or
A380, al alloy 713 relies more heavily on zinc and magnesium, with copper often present as a strengthening
element. The alloy is typically selected when a casting needs higher tensile strength and yield strength than
standard general-purpose cast aluminum alloys can provide.
In practical procurement, the first technical clarification is whether the buyer means cast 713.0/A713.0 or
another local designation. Aluminum alloy numbering can vary between Aluminum Association, ASTM, SAE, EN and
proprietary foundry specifications. For critical parts, the drawing should define the alloy designation,
temper, applicable standard, casting process and acceptance criteria.
| Term | Typical meaning in industry | Buyer note |
|---|---|---|
| Aluminum 713 | General commercial name for 713 aluminum casting alloy | Confirm whether the supplier means 713.0, A713.0 or a proprietary equivalent |
| Al alloy 713 | Abbreviated engineering or sourcing term | Should be linked to a material standard and temper |
| Al 713 | Short form used on RFQs, BOMs or machining documents | Insufficient by itself for aerospace, safety or pressure applications |
| 713.0 aluminum | Cast aluminum alloy designation | Often the most precise form for cast alloy discussions |
Typical Chemical Composition of Al Alloy 713
The exact composition limits depend on the governing standard and supplier specification. The table below
summarizes typical composition expectations for 713-type cast aluminum alloys. It should not replace the
certified composition on a mill certificate, foundry certificate or purchase specification.
| Element | Typical role | Engineering effect |
|---|---|---|
| Aluminum | Base metal | Low density, castability and corrosion resistance foundation |
| Zinc | Primary strengthening addition | Increases age-hardening response and strength |
| Magnesium | Precipitation-hardening element | Improves yield strength and hardness after aging |
| Copper | Strengthening addition | Raises strength but may reduce corrosion resistance and weldability |
| Silicon | Usually limited compared with Al-Si alloys | Affects fluidity, machinability and casting behavior |
| Iron and trace elements | Impurities or controlled minor additions | May influence ductility, hot tearing and defect sensitivity |
For a drawing or RFQ, the recommended wording is not simply “Al 713.” A more reliable description is:
“Aluminum alloy 713.0 casting, temper as specified, chemical composition and mechanical properties per
applicable standard, with certified test results.”
Mechanical Properties and Heat Treatment
Al 713 is chosen for strength-sensitive castings, but its final performance depends heavily on
casting quality, section thickness, heat treatment, aging practice, porosity level and test coupon location.
In production, separately cast test bars may show better values than properties measured from thick or highly
restrained casting sections.
| Condition | Ultimate tensile strength | Yield strength | Elongation | Typical engineering comment |
|---|---|---|---|---|
| As-cast | Moderate to high | Moderate | Low to moderate | Used when distortion control is more important than maximum strength |
| Artificially aged / T5-type practice | Often about 260-330 MPa in qualified castings | Often about 200-270 MPa | Typically about 1-4% | Common balance of strength, cost and dimensional stability |
| Solution treated and aged / T6-type practice | Can be higher when casting quality supports it | Can be higher than T5 | May decrease if over-strengthened or defect-sensitive | Requires tighter heat-treatment and distortion control |
These values are realistic engineering ranges, not guaranteed minimums. For load-bearing castings, the most
defensible specification includes tensile testing, hardness checks, heat-treatment records, radiographic or
CT inspection requirements, and agreed acceptance levels for porosity, shrinkage and inclusions.
Engineering note: why test coupons and real castings may differ
A separately cast tensile bar cools at a controlled rate and may have fewer defects than a thick boss,
rib intersection or cored section in the actual casting. In 713 aluminum, local solidification rate,
feeding quality and heat-treatment response can shift strength and elongation significantly. For critical
parts, specify properties from representative cast-on coupons or machined samples from agreed locations.
Aluminum 713 Compared with 356, 319, A380 and 7075
Material selection is rarely about the strongest alloy alone. Aluminum 713 competes with other cast and
wrought aluminum materials depending on strength target, casting method, machining allowance, corrosion
exposure, inspection level and total cost.
| Material | Material type | Strength potential | Castability / manufacturability | Best-fit use case | Limitation versus Al 713 |
|---|---|---|---|---|---|
| Aluminum 713 | Heat-treatable casting alloy | High for cast aluminum | Requires controlled foundry practice | High-strength structural castings and machined cast components | More process-sensitive than general-purpose casting alloys |
| 356 aluminum | Al-Si-Mg casting alloy | Medium to high after T6 | Excellent foundry acceptance and good weldability | General structural castings, pump parts, aerospace castings | Usually lower peak strength than optimized 713 castings |
| 319 aluminum | Al-Si-Cu casting alloy | Medium | Good castability and machinability | Engine parts, housings, automotive castings | Less attractive where high yield strength is the priority |
| A380 aluminum | Die casting alloy | Medium | Excellent for high-volume pressure die casting | Thin-wall housings, covers, brackets and consumer/industrial parts | Pressure die-cast porosity limits heat treatment and fatigue reliability |
| 7075 aluminum | Wrought plate, bar or forging alloy | Very high | Machined from wrought stock, not a casting substitute | Aircraft fittings, high-strength machined components | Higher material waste and limited near-net-shape capability |
In simple terms, 713 aluminum is attractive when the design needs a cast shape with higher strength than
356 or A380 can reliably provide, but it is not a direct replacement for wrought 7075 when the part requires
maximum fatigue performance, fracture toughness or wrought-quality grain structure.
Where Aluminum 713 Is Used
Aluminum 713 is most useful where casting geometry and mechanical load both matter. It is
considered for parts that would be expensive to machine completely from billet but still require strength
levels beyond standard commodity die castings.
- High-strength aluminum cast brackets and mounting lugs
- Aerospace-adjacent castings where certified foundry control is available
- Industrial machine frames, carriers, housings and supports
- Complex components later finished by CNC machining
- Low-to-medium volume castings where sand casting or permanent mold casting is practical
- Applications requiring a balance of lightweight design, strength and near-net-shape production
It is less suitable for highly corrosive marine environments without surface protection, welded assemblies
requiring high joint efficiency, or low-cost thin-wall pressure die castings where A380 or ADC12 would be
more economical.
Machining Aluminum 713: Practical Guidance
Al 713 can be machined successfully, but machining behavior depends on casting quality, hardness, heat
treatment and the amount of interrupted cutting caused by ribs, bosses, gates and cored surfaces. Compared
with softer aluminum casting alloys, aged 713 aluminum may require more attention to tool wear, burr control
and dimensional stability.
| Operation | Recommended focus | Reason |
|---|---|---|
| Rough milling | Use sharp carbide tools, stable workholding and adequate chip evacuation | Cast skin, hard spots and porosity can accelerate edge wear |
| Finish milling | Control tool runout and use consistent finishing stock | Improves flatness, sealing surfaces and positional accuracy |
| Drilling and tapping | Use proper lubricity and verify thread strength in cast sections | Porosity and low elongation can reduce thread reliability |
| Boring | Inspect for subsurface shrinkage before final sizing | Machining can open internal casting defects |
| Deburring | Plan mechanical or manual deburring after aging | High-strength aged aluminum may form sharp burrs on exit edges |
For precision parts, a common production strategy is rough machine, stress relieve or stabilize if required,
then finish machine critical datums. This is especially useful when casting residual stress and heat treatment
can move thin walls, long ribs or large mounting surfaces.
Real Engineering Problems and Data-Driven Controls
The performance of al alloy 713 is usually limited more by casting defects than by the nominal alloy chemistry.
A strong alloy with uncontrolled porosity can fail earlier than a lower-strength alloy with cleaner, more
consistent casting quality.
| Problem | Typical cause | Data-driven control | Expected result |
|---|---|---|---|
| Low elongation in tensile tests | Microporosity, oxide films or excessive intermetallics | Radiographic inspection, melt cleanliness control and representative coupons | More stable ductility and fewer brittle fracture events |
| Leakage after machining | Subsurface shrinkage exposed during boring or facing | CT scanning, pressure testing and casting simulation for feeding design | Lower scrap rate in hydraulic or sealed housings |
| Dimensional movement after CNC machining | Residual casting and heat-treatment stress | Intermediate stress relief, symmetric stock removal and controlled aging | Improved flatness and positional repeatability |
| Premature fatigue cracking | Surface defects, sharp fillets or internal discontinuities | Shot peening where appropriate, radius optimization and NDT acceptance limits | Better fatigue consistency under cyclic loading |
Example: in a machined cast support bracket, changing the inspection plan from only visual inspection to
visual plus radiographic inspection at high-stress bosses can reduce the risk of machining into shrinkage.
In many foundry programs, defect mapping and gating redesign produce more improvement than changing the
alloy itself.
Buyer note: documents to request for critical 713 aluminum castings
- Chemical composition certificate for each melt or heat lot
- Heat-treatment record showing time, temperature and aging practice
- Tensile test report with coupon type and sampling location
- Hardness report for production verification
- Radiographic, CT, dye penetrant or pressure-test results when applicable
- Dimensional inspection report after final machining
Corrosion, Welding and Surface Treatment
Aluminum 713 can provide useful general corrosion resistance because it remains an aluminum-base alloy, but
its zinc and copper content means it should not automatically be treated like 356 or 6061 in corrosive
environments. In outdoor, marine, chemical or galvanic contact conditions, surface protection and material
pairing should be reviewed.
Welding is generally not the preferred joining method for high-strength 713 aluminum castings. Heat input can
change local temper, create hot cracking risk and reduce mechanical properties around the weld. Mechanical
fastening, inserts, redesigning the casting as one piece, or using a more weldable alloy may be better choices.
- Anodizing may be possible, but color and finish consistency can vary with casting structure and alloy chemistry.
- Chemical conversion coating is often used where electrical conductivity and corrosion protection are needed.
- Painting or powder coating can improve environmental durability when surface preparation is controlled.
- Galvanic isolation is recommended when Al 713 contacts stainless steel, carbon steel or copper alloys in wet service.
Specification and Procurement Checklist for Al 713
The safest way to buy Al 713 is to specify performance, process and inspection together.
A drawing that lists only “Al 713” leaves too much room for disagreement over alloy equivalent, temper,
test method and acceptance standard.
| Specification item | Why it matters |
|---|---|
| Exact alloy designation | Prevents substitution with a non-equivalent aluminum casting alloy |
| Temper or heat-treatment condition | Controls strength, hardness, machinability and dimensional movement |
| Casting process | Sand casting, permanent mold casting and other methods produce different defect profiles |
| Minimum mechanical properties | Defines tensile strength, yield strength, elongation and hardness expectations |
| NDT acceptance criteria | Limits shrinkage, porosity, cracks and inclusions in critical zones |
| Machining allowance | Ensures enough material for cleanup without exposing avoidable internal defects |
| Surface treatment | Improves corrosion resistance, appearance and service durability |
| Traceability level | Supports quality audits, failure analysis and regulated-industry requirements |
When Should You Choose 713 Aluminum?
Choose Aluminum 713 when the design needs a high-strength cast aluminum component, the foundry can control
melt quality and heat treatment, and the project justifies more inspection than a commodity casting. It is
especially relevant when a near-net-shape casting can reduce machining time compared with billet machining
while still meeting structural performance targets.
Consider another alloy when weldability, corrosion resistance, very high ductility, pressure die-casting
economics or wrought fatigue performance is the main requirement. In those cases, 356, 319, A380, 6061 or
7075 may be better depending on the design route.
For engineering documentation, the best practice is to write the alloy as a complete controlled requirement:
alloy designation, temper, casting process, mechanical properties, inspection level, heat-treatment record
and machining condition. That level of detail makes 713 aluminum easier to quote, manufacture, inspect and
qualify.
