What is the difference between ADC12 and A380?

Both are high-pressure die casting alloys with similar casting behavior. ADC12 is defined by JIS H2118 (Japan) with higher silicon and lower zinc; A380 is defined by ASTM B85 (North America). In practice they are often used interchangeably, but the acceptance standard and impurity limits should be confirmed on the COA.

Is A356 better than ADC12?

Not universally. A356 has lower iron, can be heat treated (T6) and offers higher ductility, which suits structural and automotive castings. ADC12 and A380 offer better fluidity and dimensional control for high-pressure die casting of housings and enclosures. The right grade depends on the process and the part requirements.

Why does iron content matter in aluminum alloy ingots?

Iron forms hard intermetallic phases that reduce ductility and can cause porosity in thin sections. Die casting alloys tolerate more iron (about 1.0-1.3% max) because it helps prevent die soldering, while gravity or low-pressure castings and heat-treatable alloys usually specify much lower iron limits (about 0.2% max).

What should a COA for alloy ingots show?

The COA should list the actual measured composition of the lot for every element with a limit, the standard and grade designation, the heat or batch number, the production date and the quantity. Compare each measured value against the agreed specification and, for critical orders, add independent spectrometer testing.

ADC12 vs A380 vs A356: Choosing the Right Aluminum Alloy Ingot for Die Casting

TL;DR — Direct Answers

ADC12 (JIS H2118) and A380 (ASTM B85) are both high-pressure die casting alloys with similar casting behavior; ADC12 is the common choice in Asia, A380 in North America.
A356 has low iron, can be heat treated (T6) and offers higher ductility, which suits wheels, automotive structural parts and low-pressure or gravity casting.
The same grade name can have different limits under different standards, so check each lot COA against the agreed standard and add independent spectrometer testing for critical orders.

What the Grade Names Mean

Grade names come from regional standards: ADC12 is defined by JIS H2118 (Japan), A380 by ASTM B85 (North America), and A356 by ASTM A356 with equivalents in GB/T 8733 (China). Chinese alloy plants routinely produce all three, so buyers should specify the grade together with the acceptance standard.

Typical Composition Ranges Compared

Element	ADC12 (JIS H2118)	A380 (ASTM B85)	A356 (ASTM A356 / GB/T 8733)
Silicon (Si)	9.6-12.0%	7.5-9.5%	6.5-7.5%
Copper (Cu)	1.5-3.5%	3.0-4.0%	0.20% max
Iron (Fe)	1.0% max	1.3% max	0.20% max
Magnesium (Mg)	0.3% max	0.10% max	0.25-0.45%
Zinc (Zn)	1.0% max	3.0% max	0.10% max

Values above are reference ranges from common public standards, not contract terms. Standards revisions and buyer-supplier agreements can adjust limits, so always rely on the agreed specification and the actual lot COA.

ADC12 or A380?

Both are secondary die casting alloys designed for high-pressure die casting: good fluidity, good dimensional stability and economical scrap-based production. The practical differences are small: ADC12 carries higher silicon and lower zinc, while A380 allows a higher zinc ceiling. In practice, many casters treat them as interchangeable and choose by market convention — JIS-based specifications in Asia, ASTM-based specifications for North American customers. What matters more than the name is the agreed chemistry limits and the COA evidence for each lot.

When to Choose A356

Choose A356 when the part needs heat treatment (typically T6), higher ductility, or better fatigue performance — for example wheels, suspension parts and structural castings. A356 is normally produced with much tighter iron and impurity control and is commonly cast by low-pressure, gravity or permanent mold processes rather than high-pressure die casting. Its lower silicon also improves weldability and anodizing response compared with ADC12/A380.

Why Impurities Matter

Iron (Fe): the most common quality battleground. Higher iron reduces ductility and can cause porosity; die casting alloys accept about 1.0-1.3% max, while heat-treatable alloys specify about 0.20% max.
Zinc (Zn) and Magnesium (Mg): both affect corrosion resistance and mechanical properties; Mg is deliberately controlled in A356 for the T6 response.
Lead, tin and other trace elements: relevant for electrical, food-contact or specific destination-market requirements.

Secondary (scrap-based) die casting ingots carry a higher risk of iron and zinc variation, so a formal RFQ should list a maximum limit for every relevant element, not just the grade name.

How to Read a COA

Check the grade and standard match the order (for example ADC12 per JIS H2118).
Compare every measured element against the agreed limits, not just silicon.
Confirm the heat or batch number, production date and quantity match the shipment.
For critical lots, add an independent spectrometer test on a sample plan agreed in advance.

Decision Checklist

Casting process: high-pressure die casting, or low-pressure/gravity?
Heat treatment required (T6) or higher ductility demanded by the part?
Destination market standard: JIS, ASTM, GB or customer specification?
Iron and impurity limits acceptable for the application?
COA plus independent testing required before payment release?

What to Do Next

Send the grade, standard, chemistry limits, tonnage, destination and target date to Yuhua Yunchuang. We verify supplier qualification, lot documents and inspection arrangements, and confirm composition evidence order by order.