Zinc Alloy Zn99.5-O (Annealed)
Temper
ASTM B69 · EN 988 Zn99.5
Choose for deep drawing, complex press work and hand-formed ornamental work where maximum ductility is needed.
Values for the O condition
Other Zn99.5 tempers and conditions
Zn99.5 is listed in 4 conditions; see the grade overview at Zn99.5.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OThis page Annealed | Choose for deep drawing, complex press work and hand-formed ornamental work where maximum ductility is needed. | 65 | 120 | 55 | 30 HB | 28 % IACS |
Hot rolled | Thicker plate (>3 mm) for anodes, moulds, engraving/printing blocks and machined blanks. | 80 | 130 | 45 | 35 HB | 28 % IACS |
RDefault As-rolled sheet/strip | Standard stocked rolled zinc sheet/coil for roofing, flashing and cladding; best balance of strength and roll-formability. | 95 | 140 | 40 | 38 HB | 28 % IACS |
Hardened | Higher-strength thin strip for battery cans, stamped parts and spacers; note that zinc partially self-anneals at room temperature. | 140 | 180 | 25 | 47 HB | 27 % IACS |
What is Zn99.5-O?
Zn99.5-O is Zn99.5 in the O temper — choose for deep drawing, complex press work and hand-formed ornamental work where maximum ductility is needed. Zn99.5-O has a yield strength of 65 MPa (9.43 ksi) and a tensile strength of 120 MPa (17.4 ksi) — weaker than 79% of zinc alloy grades. Elongation at break is 55% and the elastic modulus is 95 GPa (13.8 Msi). Zn99.5-O has a density of 7.14 g/cm³ (0.258 lb/in³), heavier than 82% of zinc alloy grades. It melts at 420°C (787 °F). R is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- Forms and bends easily — 95/100, better than 108% of zinc alloy grades
- Ductile — tolerates forming and impact — 55%, better than 107% of zinc alloy grades
- Readily welded — 45/100, better than 107% of zinc alloy grades
- Good corrosion resistance — 55/100, better than 93% of zinc alloy grades
Limitations
- Difficult to machine — 65/100, worse than 86% of zinc alloy grades
- Low strength — 65 MPa (9.43 ksi), worse than 79% of zinc alloy grades
Zn99.5-O properties
Typical room-temperature values for Zn99.5-O; 17 are specific to this condition. Other listed values are Zn99.5 reference data and may not represent this condition. Bars are the position among zinc alloy grades.
Physical3
Zn99.5-O has a density of 7.14 g/cm³ (0.258 lb/in³), heavier than 82% of zinc alloy grades. It melts at 420°C (787 °F).
Mechanical12
Zn99.5-O has a yield strength of 65 MPa (9.43 ksi) and a tensile strength of 120 MPa (17.4 ksi) — weaker than 79% of zinc alloy grades. Elongation at break is 55% and the elastic modulus is 95 GPa (13.8 Msi).
Thermal6
Zn99.5-O is rated for continuous service to 100°C (212 °F). It conducts heat at 113 W/m·K (65.3 BTU/hr·ft·°F), better than 57% of zinc alloy grades. Thermal expansion is 30 µm/m·K (16.7 µin/in·°F).
Electrical3
Zn99.5-O conducts electricity at 28 % IACS, better than 75% of zinc alloy grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), better than 93% of zinc alloy grades.
Sustainability4
Producing a kilogram of Zn99.5-O takes about 53 MJ of energy and emits 3.6 kg of CO₂ — less than 68% of zinc alloy grades. Typical recycled content is 30%.
Manufacturability8
Zn99.5-O's machinability is good (65/100, worse than 86% of zinc alloy grades); weldability fair (45/100); formability excellent (95/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Zn99.5-O
Is Zn99.5 easy to machine?
Cuts very easily with sharp positive-rake tools and high speeds, but is gummy — use generous rake, light feeds and a lubricant to avoid built-up edge and smearing.
Can Zn99.5 be welded?
TIG/plasma or oxy-gas welding with zinc filler is possible on thick sheet but demands close heat control (melting point 419 °C); soft soldering with zinc-chloride flux is the normal joining route, along with mechanical seaming.
Can Zn99.5 be formed, bent or molded?
Excellent roll-forming, bending and standing-seam work; warm the sheet to 10–20 °C minimum (ideally 20–40 °C for tight radii) since cold zinc cracks, and bend across the rolling direction where possible.
What surface finishes work on Zn99.5?
Not anodizable — supplied mill-bright or pre-weathered/pre-patinated; chromate or phosphate conversion plus etch primer is required before painting, and contact with copper or acidic run-off must be avoided.
Zn99.5 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Pbresidual from primary refining; improves rollability | ≤ 0.45 | 0.15 |
| Fe | ≤ 0.05 | 0.02 |
| Cd | ≤ 0.01 | 0.01 |
| Cu | ≤ 0 | 0 |
| Sn | ≤ 0 | 0 |
| Al | ≤ 0.01 | 0 |
| Total impuritiessum of all non-zinc elements | ≤ 0.5 | — |
| Znminimum zinc content per EN 1179 / GB/T 470 Zn99.5 | ≥ 99.5 (balance) | — |
Zn99.5-O — frequently asked
What is Zn99.5-O used for?
Zn99.5-O is typically used for roofing and flashing, gutters and downspouts, battery can stock and gaskets and washers. In short: most formable rolled zinc; self-patinating roof sheet; commercially pure zinc grade.
What is the yield strength of Zn99.5-O?
Zn99.5-O has a typical yield strength of 65 MPa (9.43 ksi) and a tensile strength of 120 MPa (17.4 ksi) — weaker than 79% of zinc alloy grades. Strength varies by condition: see the 4 listed tempers.
Is Zn99.5-O easy to machine?
Reasonably — machinability is rated good (65/100, worse than 86% of zinc alloy grades). Cuts very easily with sharp positive-rake tools and high speeds, but is gummy — use generous rake, light feeds and a lubricant to avoid built-up edge and smearing.
Can Zn99.5-O be welded?
With care — weldability is rated fair (45/100). TIG/plasma or oxy-gas welding with zinc filler is possible on thick sheet but demands close heat control (melting point 419 °C); soft soldering with zinc-chloride flux is the normal joining route, along with mechanical seaming.
What surface finishes work on Zn99.5-O?
Not anodizable — supplied mill-bright or pre-weathered/pre-patinated; chromate or phosphate conversion plus etch primer is required before painting, and contact with copper or acidic run-off must be avoided.
Can Zn99.5-O be formed, bent or molded?
Excellent roll-forming, bending and standing-seam work; warm the sheet to 10–20 °C minimum (ideally 20–40 °C for tight radii) since cold zinc cracks, and bend across the rolling direction where possible.
What is the maximum service temperature of Zn99.5-O?
Zn99.5-O is rated for continuous use to about 100°C (212 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Zn99.5-R and Zn99.5-H?
R is the default condition — standard stocked rolled zinc sheet/coil for roofing, flashing and cladding; best balance of strength and roll-formability. H: higher-strength thin strip for battery cans, stamped parts and spacers; note that zinc partially self-anneals at room temperature. Yield strength is 95 MPa in R versus 140 MPa in H.
Sources
- EN 988 — Zinc and zinc alloys: specification for rolled flat products for building — CEN (1997)
- EN 1179 — Zinc and zinc alloys: primary zinc — CEN (2003)
- GB/T 470 — SAC (2008)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Zinc and Zinc Alloys) — ASM International (1990)
- ASM Metals Reference Book, 3rd ed. — ASM International (1993)
- International Zinc Association / ILZRO rolled zinc property data — IZA (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.