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 |
TABLE 1 Chemical Requirements Composition, % (Range or Maximum Value)A
| 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) | |
| UNSB | 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 | ... |
| SbC | ... | ... | ... | ... | ... | ... | 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 |
| ZnD | Remainder | Remainder | Remainder | Remainder | Remainder | Remainder | Remainder |
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.
1.2The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.3This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to become familiar with all hazards including those identified in the appropriate Safety Data Sheet (SDS) for this product/material as provided by the manufacturer, to establish appropriate safety, health and environmental practices, and determine the applicability of regulatory limitations prior to use.
1.4This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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