1.1This specification covers zinc master alloys which are used in hot dip galvanizing for the purpose of adjusting the concentration of certain alloying elements in the molten zinc bath. Table 1 covers the chemical composition of these materials which include six master alloys of zinc-aluminum (brightener) and one master alloy of zinc-antimony.

ASTM	Common		UNS
Type A-1	90/10 Zn/Al	High Purity	Z30750
Type A-2	90/10 Zn/Al	Low Purity	Z31710
Type A-3	95/5 Zn/Al	High Purity	Z30503
Type A-4	95/5 Zn/Al	Low Purity	Z31510
Type A-5	96/4 Zn/Al	High Purity	Z31520
Type A-6	96/4 Zn/Al	Low Purity	Z30504
Type S-1	90/10 Zn/Sb		Z55710

Type A-1	90 % Zinc-10 % Aluminum (90/10 Zn/Al)	High Purity
Type A-2	90 % Zinc-10 % Aluminum (90/10 Zn/Al)	Low Purity
Type A-3	95 % Zinc-5 % Aluminum (95/5 Zn/Al)	High Purity
Type A-4	95 % Zinc-5 % Aluminum (95/5 Zn/Al)	Low Purity
Type A-5	96 % Zinc-4 % Aluminum (96/4 Zn/Al)	High Purity
Type A-6	96 % Zinc-4 % Aluminum (96/4 Zn/Al)	Low Purity
Type S-1	90 % Zinc-10 % Antimony (90/10 Zn/Sb)

UNS^B	Type A-1 90/10 Zn/Al Z30750	Type A-2 90/10 Zn/Al Z31710	Type A-3 95/5 Zn/Al Z30503	Type A-4 95/5 Zn/Al Z31510	Type A-5 96/4 Zn/Al Z31520	Type A-6 96/4 Zn/Al Z30504	Type S-1 90/10 Zn/Sb Z55710
Fe	0.05 max	0.15 max	0.05 max	0.15 max	0.05 max	0.15 max	0.03 max
Pb	0.005 max	0.4 max	0.005 max	0.4 max	0.005 max	0.4 max	0.015 max
Cd	0.004 max	...	0.004 max	...	0.004 max	...	0.003 max
Cu	0.035 max	0.5 max	0.035 max	0.5 max	0.035 max	0.5 max	0.003 max
Mg	...	...	...	...	0.06 max	0.06 max
Sn	0.003 max	...	0.003 max	...	0.003 max	...	0.01 max
As	...	...	...	...	...	...	0.015 max
Al	9.5-10.5	9.5-10.5	4.5-5.5	4.5-5.5	4.0-4.5	4.0-4.5	...
Sb^C	...	...	...	...	...	...	9.5-10.5
Others, Total	0.01 max	0.25 max	0.01 max	0.25 max	0.01 max	0.25 max	0.03 max
Zn^D	Remainder	Remainder	Remainder	Remainder	Remainder	Remainder	Remainder

(A)The following applies to all specified limits in this table: For purposes of determining conformance with this specification, an observed value obtained from analysis shall be rounded off to the nearest unit in the last right-hand place of figures used in expressing the limiting value, in accordance with the rounding method of Practice E29.

(B)UNS numbers in conformance with Practice E527.

(C)Chemical method under development.

(D)For information only. Quantitative determination of this element is not required. Zinc is assumed to be the difference between 100 % and the sum of those elements listed above.

Note 1:The master alloys in Specification B860 are intended to be used primarily in hot-dip galvanizing to adjust the concentration of certain elements in a molten zinc bath, and differ from the zinc-aluminum alloys in Specification B997 which are intended to be used primarily in molten zinc-aluminum.