A413 aluminum (ANSI/AA A413.0) carries higher silicon and lower copper than A380, which translates into measurably better pressure tightness, higher fluidity for thin-wall sections, and a documented corrosion-resistance advantage for outdoor and sealed-housing duty [S3][S6].
A380 (ANSI/AA A380.0) remains the highest-volume aluminum die casting alloy because it pairs competitive strength with the lowest unit cost and the broadest machining/finishing response; it offers "good corrosion resistance in outdoor environments" but is not the benchmark alloy for that criterion [S3][S7].
Alloy Chemistry and Why It Drives Corrosion Behavior
A380 nominally contains 7.5–9.5% Cu, 3.0–3.5% Mg range with Fe held below 1.3%, and 7.5–9.5% Si; that copper content is the dominant driver of its outdoor corrosion penalty because Cu-rich intermetallics create galvanic microcells against the aluminum matrix [S3].
A413 nominally contains 11.0–13.0% Si with copper held to a maximum of 1.0% and magnesium in the 0.05–0.50% band; the lower Cu and higher Si shift the microstructure toward harder, more passive behavior in moist environments, which is why industry guidance ranks A413 above A380 for corrosion and pressure-tight service [S3][S4][S6].
For buyers mapping an aluminum die casting decision, this is the single largest material-side lever: dropping copper from the 7.5–9.5% band to under 1.0% materially changes long-term atmospheric corrosion rate, even before any coating is applied [S3].
Mechanical, Thermal and Castability Trade-Offs vs Corrosion
Typical-property snapshots from NADCA show A380 at roughly 324 MPa ultimate tensile, 159 MPa yield, 80 Brinell and 3.5% elongation; A413 drops to about 290 MPa ultimate, 130 MPa yield and 80 Brinell with elongation falling to 2.5–3.5%, so A413 trades roughly 10–15% tensile strength for its sealing and corrosion gains [S3][S4].
A413's higher silicon gives it the best fluidity in the Al-Si-Cu family, which is why NADCA calls it out specifically for hydraulic cylinders, pressure vessels, intricate housings and heat-sink frames where the part has to fill thin sections before it has to take a high load [S3][S5].
A360 sits between the two for corrosion (lower Cu at 0.6% max, Mg 0.40–0.60%) and is repeatedly cited as the best-in-class die cast aluminum for outdoor and marine service; A360 is, however, harder to cast than A380, and most foundries quote longer cycle times or higher scrap risk on it [S3][S4][S8].
Decision Matrix: A413 vs A380 vs A360 for Outdoor Housings
Ranked on four buyer criteria drawn from NADCA and die caster guidance, with a 1–5 scale (5 = best for outdoor housing duty): corrosion resistance: A360 = 5, A413 = 4, A380 = 3; pressure tightness/leak risk: A413 = 5, A360 = 4, A380 = 3; thin-wall castability: A413 = 5, A360 = 4, A380 = 3; cost and machine-shop familiarity: A380 = 5, A413 = 4, A360 = 3 [S1][S3][S4][S6][S8].
If the housing is a sealed outdoor electronics enclosure with thin walls and a gasket face, A413 is the engineering default; if the housing is a general-purpose bracket or engine cover in mild atmosphere, A380 is the procurement default because unit cost and CNC feed rates dominate [S1][S3][S5].
For coastal or salt-spray exposure, A360 should be the first alloy reviewed, with A413 as a strong second; A380 in that service is acceptable only behind a qualified coating system and an agreed inspection cadence [S4][S8].
Coating, Finishing and Inspection Reality Check
A380 accepts chromate, powder coat, anodize (Type I/II limited) and e-coat with the widest process window in the family, which is part of why it remains the default for outdoor enclosures even where corrosion is a concern; A413 is similar in coating response but has fewer published finishing data points from general-purpose die casters [S3][S7].
For any outdoor housing, the alloy pick and the coating system have to be qualified together: A413 plus a powder coat over a chromate conversion layer will outperform A380 plus the same coating in salt-spray testing, but neither alloy should be specified without an ASTM B117 salt-spray target (commonly 240–1000 h depending on the warranty) written into the drawing notes [S4][S8].
Machining behavior matters in practice: A380 is rated better than average for machining in the NADCA table, while A413 sits at average because the higher free-silicon content accelerates tool wear on tight tolerance features; if the housing needs many M-class tapped holes, A380 has a measurable cost advantage on tooling life [S3].
Where Each Alloy Fits and Where It Does Not
A413 is the right call for outdoor sealed housings, LED heat-sink bodies, thin-wall covers, pump bodies, and any pressure-tight casting where leak rate is a release criterion; it is the wrong call when the part carries high mechanical load, needs heavy secondary machining, or has to hit the lowest piece-price in a non-corrosive indoor environment [S1][S2][S3][S6].
A380 is the right call for general-purpose indoor brackets, gear cases, engine accessories, lawn-mower housings, and cost-driven outdoor parts behind a coating; it is the wrong call for leak-sensitive hydraulic bodies, very thin walls under 2 mm, or coastal installations where the coating maintenance schedule cannot be guaranteed [S1][S3][S5][S7].
A360 belongs in any outdoor housing spec where corrosion is the primary risk and the buyer can accept longer die-cast cycle times, higher scrap risk, and a smaller supplier base; A518 (Mg-based) is the better finishing-and-corrosion choice when the part can tolerate a permanent-mold or semi-solid casting route instead of high-pressure die casting [S3][S8].
Sourcing, Standards and Drawing Notes to Lock In
Call out the alloy on the drawing by ANSI/AA designation (A380.0, A413.0 or A360.0), reference NADCA Product Specification Standards for Die Castings for chemistry and typical-property tables, and require the foundry to certify the actual chemistry lot-by-lot rather than relying on a generic "aluminum die cast" callout [S3].
For an outdoor housing, add three drawing notes that drive real-world performance: a salt-spray test target (ASTM B117 hours), a leak or pressure-tightness test threshold if the part is sealed, and an explicit surface-finish or coating system tied to the warranty in years; without these, an alloy change from A380 to A413 cannot be evaluated on inspection [S3][S4][S6].
For buyers comparing process and material options across a wider die-casting program, the trade-offs above mirror the same castability-vs-corrosion logic used in 80 m/s vs 50 m/s fettling wheels where wheel speed trades against surface integrity; the principle is identical, only the medium changes from abrasive to molten aluminum.
The underlying component specifications are covered under cast iron, and decade resistance box.