A360 is an aluminum-silicon-magnesium casting alloy with 9.0 to 10.0% silicon and copper held to 0.6% maximum, and that copper limit is what gives it markedly better corrosion resistance than A380. As cast it reaches 317 MPa tensile strength, 170 MPa yield strength and 75 HB hardness, with 113 W/m·K thermal conductivity and excellent pressure tightness.
A360 is an aluminum-silicon-magnesium casting alloy with 9.0 to 10.0% silicon and copper held to 0.6% maximum, and that copper limit is what gives it markedly better corrosion resistance than A380. As cast it reaches 317 MPa tensile strength, 170 MPa yield strength and 75 HB hardness, with 113 W/m·K thermal conductivity and excellent pressure tightness.
A360 is the alloy to specify when the environment or the seal is the problem rather than the price. Removing copper eliminates the copper-rich intermetallic particles that drive galvanic pitting, so corrosion resistance moves from fair to good. Its solidification behaviour leaves fewer interdendritic leak paths, which is why pressure tightness is rated excellent and why hydraulic bodies and IP-rated enclosures are cast in it. The 0.4 to 0.6% magnesium also lifts yield strength to 170 MPa, the highest of the common die casting alloys.
The trade-offs are real and we will state them plainly. A360 is harder to run than A380: the process window is narrower, the melt is more prone to soldering to the die, and scrap rates are higher, so ingot and piece price both sit above A380. Without copper to help chips break, machining is good rather than very good. Specify A360 when corrosion, sealing or heat dissipation justify that, and A380 when they do not.
| ASTM designation | A360 / 360.0 (ASTM B85, UNS A03600) |
|---|---|
| Equivalent grades | ADC3 (JIS), EN AC-43400, YL104 (GB) |
| Ultimate tensile strength | 317 MPa (46 ksi) |
| Yield strength (0.2% offset) | 170 MPa (25 ksi) |
| Elongation in 50 mm | 3.5% |
| Brinell hardness | 75 HB |
| Silicon content | 9.0-10.0% |
| Copper content | 0.6% max |
| Magnesium content | 0.40-0.60% |
| Density | 2.63 g/cm³ |
| Thermal conductivity | 113 W/m·K |
| Melting range | 557-596 °C |
A360 is an aluminum-silicon-magnesium die casting alloy standardised in ASTM B85 as alloy 360.0, with the UNS number A03600 and the European chemical designation AlSi10Mg. Silicon between 9.0 and 10.0% provides castability, magnesium between 0.40 and 0.60% provides strength through Mg2Si precipitation, and copper is deliberately restricted to 0.6% maximum.
That copper restriction is the whole point of the alloy. In A380, 3.0 to 4.0% copper forms Al2Cu particles that sit at a different electrochemical potential from the surrounding aluminum, creating microscopic galvanic cells that drive pitting in humid and salty environments. Take the copper out and the driver goes with it. A360 therefore rates good for corrosion resistance where A380 rates fair, and it is the grade we recommend for outdoor and washdown service.
A360 is also the strongest of the common die casting alloys in the sense that usually matters for design. Its ultimate tensile strength of 317 MPa is slightly below A380's 324 MPa, but its 0.2% yield strength is higher at 170 MPa against 159 MPa, because Mg2Si raises the stress at which permanent deformation begins. For a part sized against permanent set rather than fracture, A360 carries more load.
The composition below is the ASTM B85 specification for alloy 360.0. Two limits define the alloy: copper at 0.6% maximum, which delivers the corrosion performance, and magnesium at 0.40 to 0.60%, which delivers the yield strength. Iron is kept lower than in A380 because iron-bearing needle phases reduce both ductility and corrosion resistance in an Al-Si-Mg alloy.
| Element | Min % | Max % | Function in the alloy |
|---|---|---|---|
| Silicon (Si) | 9.0 | 10.0 | Provides fluidity and low shrinkage; the narrow band keeps solidification behaviour consistent |
| Magnesium (Mg) | 0.40 | 0.60 | Forms Mg2Si, which raises yield strength to 170 MPa, the highest of the common die casting alloys |
| Copper (Cu) | — | 0.6 | Deliberately restricted; this single limit is what lifts corrosion resistance from fair to good |
| Iron (Fe) | — | 1.0 | Needed to prevent die soldering but held tighter than in A380, because iron needles cut ductility and corrosion performance |
| Manganese (Mn) | — | 0.35 | Converts needle-shaped iron phases into a rounded, less damaging morphology |
| Nickel (Ni) | — | 0.50 | Residual from feedstock; contributes slight elevated-temperature strength |
| Zinc (Zn) | — | 0.50 | Held far tighter than A380's 3.0% allowance, because zinc degrades corrosion resistance |
| Tin (Sn) | — | 0.15 | Tightly limited; tin depresses both strength and corrosion performance |
| Others, total | — | 0.25 | Combined residual allowance, half that permitted in A380 |
| Aluminum (Al) | Balance | Balance | Base metal, typically 88 to 90% of the alloy |
The ASTM casting specification permits up to 2.0% iron, but for A360 we buy ingot to 1.0% maximum and aim for 0.7 to 0.9% in the furnace. That is enough iron to protect the die steel while preserving the corrosion resistance the alloy is being specified for. Every ingot lot is spectrometer verified before it enters the melt.
Two numbers in this table drive most A360 decisions. The first is 170 MPa yield strength, the highest of the common die casting alloys and 7% above A380. The second is 113 W/m·K thermal conductivity, 18% above A380's 96 W/m·K, which is what makes A360 the practical choice for cast heat sinks and for housings that must shed the heat of the motor or driver inside them.
The third number worth naming is density: 2.63 g/cm³, the lightest of the common die casting alloys, because there is no copper. On a large housing that difference is 4% of part mass against A380, which matters for shipping cost on high-volume programs and for anything that moves.
| Property | Value | Notes |
|---|---|---|
| Ultimate tensile strength | 317 MPa (46 ksi) | Separately cast test bar, as-cast condition |
| Yield strength (0.2% offset) | 170 MPa (25 ksi) | Highest of the common die casting alloys, from Mg2Si strengthening |
| Elongation in 50 mm | 3.5% | The same as A380; A360's advantage is yield strength, not ductility |
| Shear strength | 179 MPa (26 ksi) | Relevant to fastener bosses and cover flanges |
| Fatigue strength | 124 MPa (18 ksi) | R.R. Moore rotating beam, 5 × 10⁸ cycles |
| Modulus of elasticity | 71 GPa | Stiffness comes from section geometry, not the alloy |
| Brinell hardness | 75 HB | 500 kg load, 10 mm ball |
| Density | 2.63 g/cm³ | The lightest of the common die casting alloys |
| Melting range | 557-596 °C | A 39 °C freezing range, narrower than A380's 55 °C |
| Thermal conductivity | 113 W/m·K | 18% above A380; the reason A360 is used for cast heat sinks |
| Coefficient of thermal expansion | 21.0 µm/m·°C | Measured 20 to 100 °C |
| Electrical conductivity | 29% IACS | Higher than A380's 23% because copper is absent from solution |
Typical as-cast values on separately cast test bars, consistent with the master alloy comparison used across this site. Properties in a real casting vary with wall thickness and local solidification rate.
Aluminum protects itself with a thin, self-repairing oxide film. What breaks that protection down in a die casting is not the aluminum but the second-phase particles distributed through it. Copper-rich Al2Cu sits at a more noble potential than the aluminum matrix, so in the presence of an electrolyte, chloride-bearing salt spray being the worst case, the matrix around each particle corrodes preferentially and pits form.
Cutting copper from 3.0 to 4.0% down to 0.6% maximum removes the dominant driver of that mechanism. It does not make A360 stainless. Bare A360 will still stain and pit in coastal air over time, and neither alloy belongs in continuous immersion. What A360 buys is margin: a coating scratch on an A360 housing does not become a corrosion site as quickly, which is exactly the failure mode that gets outdoor equipment returned.
| Service environment | A380 (3.0-4.0% Cu) | A360 (0.6% Cu max) | Recommended finish |
|---|---|---|---|
| Conditioned indoor, dry | Suitable bare | Suitable bare | Shot blast only |
| Indoor with condensation or washdown | Coating advised | Suitable bare | Chromate conversion coating |
| Outdoor, sheltered | Coating required | Suitable with light coating | Chromate or powder coat |
| Outdoor, industrial atmosphere | Coating required | Coating advised | Powder coat |
| Coastal or salt spray exposure | Not recommended bare | Coating required | Chromate plus powder coat, isolated fasteners |
| Continuous immersion | Not recommended | Not recommended | Specify a different material or a qualified coating system |
Ratings follow the master alloy comparison, which rates A380 corrosion resistance as fair and A360 as good. Where a part faces mixed metals in a wet environment, galvanic isolation at the fastener and gasket interfaces usually matters more than the choice between these two alloys.
A360 is rated excellent for pressure tightness where A380 is rated good, and the reason is metallurgical rather than procedural. Copper-bearing alloys finish solidifying through low-melting copper-rich eutectics, which leaves interconnected interdendritic shrinkage on the last regions to freeze. Those channels are the leak paths that show up on a helium or air-under-water test after a face is machined open. A360's narrower 39 °C freezing range and absence of copper eutectics leave fewer of them.
Alloy choice is necessary but not sufficient for a leak-tight part. Pressure tightness is designed in: uniform walls, no isolated thick sections, gates positioned so that the last metal to freeze is in an overflow rather than in the sealing face, and vacuum assist where the geometry demands it. We leak test to your specified pressure and can impregnate castings where a design leaves no better option.
The thermal case is simpler. At 113 W/m·K, A360 moves roughly 18% more heat than A380 for the same fin geometry, and it does so at lower density. For LED and power electronics housings that are also the heat sink, that is often the difference between passing a thermal test with cast fins and needing a separate extruded or bonded-fin assembly. A413 conducts better still at 121 W/m·K, but its yield strength is lower at 145 MPa and its machinability only fair, so A360 is usually the better balance.
With copper capped at 0.6% maximum, the galvanic couples that pit A380 are largely absent. A360 handles humid indoor service bare and outdoor service with a straightforward coating, and it degrades far more gracefully when that coating is scratched in the field.
Fewer interdendritic leak paths mean fewer parts failing a leak test after machining opens a sealing face. For hydraulic bodies, manifolds and IP-rated enclosures, A360 raises first-pass yield enough to offset the higher ingot price.
170 MPa against 159 MPa for A380 and 150 MPa for ADC12, from Mg2Si precipitation. Where a bracket or flange is sized against permanent deformation rather than fracture, A360 carries the most load of the four grades we cast.
113 W/m·K against 96 W/m·K for both A380 and ADC12. On a housing that doubles as a heat sink, that 18% margin is frequently what lets cast fins replace a separate thermal assembly.
2.63 g/cm³, roughly 4% lighter than A380, because there is no copper. On high-volume shipped products and on anything that accelerates or is carried, that weight saving compounds across the program.
Removing copper produces a more even anodic film, and Al-Si-Mg chemistry responds better to chromate and conversion coatings. The 9 to 10% silicon still yields a grey rather than clear finish, so this is an improvement over A380 rather than a match for wrought 6061.
Castability is rated very good rather than excellent. The process window is narrower, the alloy is more prone to soldering to the die, cycle times run slightly longer and scrap rates are higher. That shows up as cost and as more process development on a new tool.
Relative cost is moderate against A380's lowest, from both ingot price and casting yield. A360 should be specified because the part needs its properties, not as a general upgrade. We quote both alloys where the choice is genuinely open.
Without copper to harden the matrix, chips tend to smear rather than break and built-up edge forms more readily, so machinability drops to good. Sharp carbide or polycrystalline diamond tooling, higher surface speed and generous coolant handle it, but heavily machined parts are cheaper in A380.
Both alloys publish 3.5% elongation in 50 mm on separately cast test bars. A360 is often described as the more ductile grade, and in an as-cast high pressure die casting that is not supported by the data. Its real advantages are yield strength, corrosion resistance, pressure tightness and thermal conductivity.
The 0.4 to 0.6% magnesium in A360 would respond to a T6 treatment in a permanent mold or squeeze casting, but in high pressure die casting the entrapped gas blisters at solution temperature. Only a T5 stabilisation is realistic, so plan around as-cast properties.
Good is not excellent. In salt spray, coastal air or chemical exposure, A360 needs a coating system and galvanic isolation at fastener and gasket interfaces, and it is not suitable for continuous immersion in any case.
The comparison against A380 is a straight exchange: A360 gives up castability, machinability and cost, and gains corrosion resistance, pressure tightness, thermal conductivity, yield strength and a little weight. If none of those gains is needed, A380 is the better commercial answer, and we will say so.
Against ADC12 the picture is similar with one addition: ADC12's higher silicon fills thinner walls than A360 does. A part that needs both a 1.2 mm wall and outdoor corrosion performance is a genuine engineering conflict, and it is usually resolved by holding the wall at 1.5 mm in A360 or by accepting ADC12 with a qualified coating system.
A413 is worth mentioning where heat is the whole requirement. At 11.0 to 13.0% silicon it conducts best of the four at 121 W/m·K and it is excellent for pressure tightness, but yield strength falls to 145 MPa and machinability to fair. For most heat sink housings that also carry mounting loads and machined interfaces, A360 remains the better balance.
| Property | A380 (AlSi8Cu3Fe) | ADC12 (A383) | A360 (AlSi10Mg) | A413 (AlSi12) |
|---|---|---|---|---|
| Ultimate tensile strength | 324 MPa (47 ksi) | 310 MPa (45 ksi) | 317 MPa (46 ksi) | 296 MPa (43 ksi) |
| Yield strength (0.2%) | 159 MPa (23 ksi) | 150 MPa (22 ksi) | 170 MPa (25 ksi) | 145 MPa (21 ksi) |
| Elongation in 50 mm | 3.5% | 3.5% | 3.5% | 2.5% |
| Brinell hardness | 80 HB | 75 HB | 75 HB | 80 HB |
| Silicon content | 7.5-9.5% | 9.6-12.0% | 9.0-10.0% | 11.0-13.0% |
| Copper content | 3.0-4.0% | 1.5-3.5% | 0.6% max | 1.0% max |
| Density | 2.74 g/cm³ | 2.70 g/cm³ | 2.63 g/cm³ | 2.66 g/cm³ |
| Thermal conductivity | 96 W/m·K | 96 W/m·K | 113 W/m·K | 121 W/m·K |
| Castability | Excellent | Excellent | Very good | Excellent |
| Corrosion resistance | Fair | Fair | Good | Good |
| Machinability | Very good | Good | Good | Fair |
| Pressure tightness | Good | Good | Excellent | Excellent |
| Relative cost | Lowest | Low | Moderate | Moderate |
Properties are typical as-cast values measured on separately cast test bars and will vary with wall thickness, gating and section geometry. Request a material certificate for lot-specific values.
Real parts we have manufactured that involved this capability.
A European industrial pump manufacturer converted a billet-machined housing to A360 die casting to reach 8,000 units a year, holding 6 bar pressure tightness, an H7 bearing bore and a 0.05 mm sealing face.
An LED lighting brand replaced a bonded two-piece design, an extruded heat sink adhered to a die cast housing, with a single A413 casting, removing the thermal interface and taking 11 °C off the LED junction temperature at 60,000 units a year.
Because copper is capped at 0.6% maximum in A360 against 3.0 to 4.0% in A380. Copper forms Al2Cu particles that sit at a more noble electrochemical potential than the surrounding aluminum, so in the presence of moisture and especially chlorides the matrix around each particle corrodes preferentially and pits initiate. Remove the copper and you remove the driver. A360 is rated good for corrosion resistance against A380's fair, which in service terms means it can be used bare in humid indoor conditions and coated with confidence outdoors.
No, and this is a common misconception worth correcting. Both alloys publish 3.5% elongation in 50 mm as typical as-cast values on separately cast test bars, so there is no ductility advantage to A360 in a high pressure die casting. What A360 does offer is a higher 0.2% yield strength of 170 MPa against 159 MPa, meaning it withstands more stress before permanent deformation, plus better corrosion resistance, excellent pressure tightness and 113 W/m·K thermal conductivity against 96 W/m·K. Specify A360 for those reasons rather than for ductility.
Yes. At 113 W/m·K, A360 conducts roughly 18% more heat than A380 or ADC12 at 96 W/m·K, and it does so at a lower density of 2.63 g/cm³. For LED lighting housings, motor housings and power electronics enclosures that must dissipate heat through cast fins, that margin often decides whether the part passes a thermal test without a separate heat sink assembly. A413 conducts better still at 121 W/m·K, but its 145 MPa yield strength and fair machinability make it a worse fit where the same part also carries mounting loads and machined interfaces.
Yes, and A360 is the alloy we recommend for it. Its narrower 39 °C freezing range and absence of copper-rich eutectics leave fewer interdendritic leak paths than A380, which is why it is rated excellent rather than good for pressure tightness. Alloy choice alone is not enough: the design needs uniform walls with no isolated thick sections, gating arranged so the last metal to freeze ends up in an overflow rather than a sealing face, and vacuum assist where the geometry demands it. We leak test to your specified pressure and can impregnate castings where the design leaves no better option.
Two reasons, roughly equal in weight. Ingot costs more, because holding copper below 0.6% and iron below 1.0% requires cleaner feedstock than the secondary metal that A380 tolerates at up to 3% zinc and 4% copper. Casting yield is lower, because A360's narrower process window, greater tendency to solder to the die and slightly longer cycle time all raise scrap and reduce hourly output. The master alloy comparison reflects this as moderate relative cost against A380's lowest. The premium is worth paying when corrosion, sealing or thermal performance is a requirement, and not otherwise.
They are close equivalents. A360 is the ASTM B85 grade, AlSi10Mg is its chemical designation, EN AC-43400 (AlSi10Mg(Fe)) is the EN 1706 die casting grade and ADC3 is the JIS equivalent. All are aluminum-silicon-magnesium alloys with 9 to 11% silicon, low copper and 0.2 to 0.6% magnesium. EN AC-43400 restricts copper harder at 0.10% maximum and iron at 1.0%, so it is slightly cleaner than the ASTM grade. If your drawing specifies EN AC-43400 we buy ingot to the EN chemistry and certify against EN 1706 rather than substituting standard A360.
A360 is the right choice among the die casting alloys for coastal service, but it still requires a coating. Its good corrosion rating means it resists the pitting that copper-bearing A380 suffers, and a scratch through the coating does not become a corrosion site nearly as fast. For salt spray exposure we recommend a chromate conversion coating followed by powder coat, galvanic isolation at fastener and gasket interfaces, and drainage designed into the geometry so water cannot pool. For continuous seawater immersion, neither A360 nor any standard die casting alloy is appropriate.
Send your 2D drawing and 3D model with the environment, sealing pressure or thermal target the part has to meet. We will confirm whether A360 is justified over A380, quote piece price and tooling, and return a written DFM report covering the leak paths in your geometry.