Definition of ADC-3 Corrosion Resistance
The trade-off is castability. A360 rates 3 of 5 for die filling and asks more of the tooling and the process, which makes supplier experience matter. Taiwan foundries run both alloy families routinely. JoinCast casts ADC-3 for marine hardware and outdoor housings at its Changhua plant and salt spray tests finished parts in its own lab.
Why This Matters for Your Business
Be careful about assuming the alloy alone solves the problem. ADC-3 resists corrosion better than ADC-12, but a marine part still normally needs a coating, and galvanic contact with stainless fasteners can undo the benefit. Specify the coating and the fastener material together.
Ask a prospective supplier how often they pour ADC-3 and whether they salt spray test finished parts. A foundry running ADC-12 almost exclusively may quote the alloy and then struggle with fill at the first tool trial, which costs you weeks.
Related Terms
ADC-12 castability and mechanical properties Aluminum alloy selection criteria Material traceability in die casting Mold Flow Simulation Shot Parameters and Metal Fill RateFAQ
How much better is ADC-3 corrosion resistance than ADC-12 in a marine application?
ADC-3 corrosion resistance is meaningfully better than ADC-12, and copper content is the reason. NADCA's 2021 ratings put A360, the ADC-3 equivalent, at 2 of 5 for corrosion resistance while A380 sits at 4, where 5 is the least desirable score. ADC-12 falls between them at 3. Less copper means less galvanic activity at the surface once salt and moisture are present.
Even so, no die casting alloy survives long marine exposure unprotected. Pair the alloy with anodizing or powder coating and agree a salt spray duration in the specification. Our marine component die casting page describes how these parts are produced and tested.
Does specifying ADC-3 corrosion resistance affect my tooling cost or lead time?
ADC-3 corrosion resistance comes with lower fluidity than ADC-12, so the alloy asks more of the mold. NADCA rates A360 at 3 of 5 for die filling against 1 for A383. In practice, gating, venting and thermal balance need more attention during design, and a thin-wall part may need its wall thickness revised to fill cleanly. Tooling cost is not automatically higher, but a weak tool design shows the difference sooner.
Flow analysis before steel is cut removes most of that risk. JoinCast's mold engineering service models fill and solidification while the tool is still on screen, which costs far less than cutting a second die.
When should I choose ADC-3 corrosion resistance over a coated ADC-12 part?
ADC-3 corrosion resistance earns its place when the coating cannot be relied on for the whole service life. Machined faces, drilled holes and handling damage all expose bare metal, and on a coated ADC-12 part that bare metal corrodes quickly in salt air. With ADC-3 the substrate itself resists attack, so a scratch is far less consequential.
For a sealed indoor part, coated ADC-12 is normally the cheaper and better answer. Regional naming causes confusion in this comparison, and our article on die casting alloy names across regions maps ADC-3 to A360 and its European equivalents. Both alloys are stocked routinely in Taiwan, so either can normally be quoted without a lead time penalty.
