ZAMAK 7

Zamak 7 (ASTM AG40B), or Zinc Alloy 7, is a modification of Zamak 3. It is a high-purity alloy containing lower magnesium content and has a tighter impurities specification. This results in improved casting fluidity, ductility and surface finish.

Zamak 7 has less magnesium than zamak 3 to increase fluidity and ductility, which is especially useful when casting thin wall components. In order to reduce inter-granular corrosion a small amount of nickel is added and impurities are more strictly controlled.

Zamak 7, or Zinc Alloy 7, is a modification of Alloy 3. It is a high-purity alloy containing lower magnesium content and has a tighter impurities specification. This results in improved casting fluidity, ductility and surface finish. Zamak 7 is mostly used for special hardware applications, or when castings require extra formability during subsequent assembly operations such as crimping or staking. Its higher fluidity also allows thinner walls to be cast.

Applications ideal for Zamak 7

Zamak 7 is mostly used for special hardware applications, or when castings require extra formability during subsequent assembly operations such as crimping or staking. Its higher fluidity also allows thinner walls to be cast:

Higher fluidity is sometimes desirable especially on components with intricate detail, however it does present special casting considerations
In order to avoid excessive flashing along the tool parting lines, good die fit and close control of casting process parameters is necessary
The high ductility exhibited by this alloy also has an impact on processing, but mainly in secondary operations for flash removal and trimming
Zamak 7 exhibits excellent damping capacity and vibration attenuation in comparison with aluminum die casting alloys

ZAMAK 7 COMPOSITION AS PER STANDARD
		Alloying elements			Impurities
STANDARD	LIMIT	AL	CU	MG	Pb	Cd	Sn	Fe	Ni	Si	In	Tl
ASTM B86 (Ingot)	Min	3.5	-	0.005	-	-	-	-	0.005	-	-	-
ASTM B86 (Ingot)	Max	4.3	0.25	0.02	0.003	0.002	0.001	0.075	0.02	-	-	-