Aluminum 3A21-H16
Temper
GB 3A21 · UNS A93003
H16 = strain hardened, three-quarter hard
Use where higher strength and dent resistance matter and only mild bending is required.
Values for the H16 condition
Other 3A21 tempers and conditions
3A21 is listed in 10 conditions; see the grade overview at 3A21.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for maximum ductility: deep drawing, spinning, tube bending, complex-formed vessels. | 42 | 110 | 33 | 28 HB | 50 % IACS |
As fabricated | As-extruded/as-forged stock bought for subsequent forming or annealing; mechanical properties not guaranteed. | 45 | 110 | 25 | 29 HB | 48 % IACS |
Strain hardened from hot working only | Standard condition for hot-rolled thick plate, extruded tube/bar and forged blanks of 3A21. | 50 | 115 | 22 | 30 HB | 49 % IACS |
Strain hardened and partially annealed, quarter hard | Same strength class as H12 but with extra residual ductility — choose for formed parts made from light-gauge coil. | 110 | 130 | 14 | 35 HB | 42 % IACS |
Strain hardened, quarter hard | Light cold work when moderate stiffness is needed but the part still has to be roll-formed or bent. | 125 | 130 | 10 | 35 HB | 42 % IACS |
Strain hardened and partially annealed, half hard | Very common Chinese stock condition for 3A21 coil/sheet needing H14-level strength plus bendability. | 135 | 150 | 11 | 40 HB | 41 % IACS |
H14Default Strain hardened, half hard | The default stocked sheet/coil condition: balanced strength, flatness and workability for panels, tanks and ducting. | 145 | 150 | 8 | 40 HB | 41 % IACS |
Strain hardened and partially annealed, three-quarter hard | H16 strength level with improved bend behaviour; used for roll-formed profiles and shutter/fin stock. | 160 | 180 | 8 | 46 HB | 40 % IACS |
H16This page Strain hardened, three-quarter hard | Use where higher strength and dent resistance matter and only mild bending is required. | 170 | 180 | 5 | 47 HB | 40 % IACS |
Strain hardened, full hard | Maximum strength/springiness of the alloy; for flat parts, fin stock and shells that need no further forming. | 185 | 200 | 4 | 55 HB | 40 % IACS |
What is 3A21-H16?
3A21-H16 is 3A21 in the H16 temper — use where higher strength and dent resistance matter and only mild bending is required. 3A21-H16 has a yield strength of 170 MPa (24.7 ksi) and a tensile strength of 180 MPa (26.1 ksi) — weaker than 56% of aluminum grades. Elongation at break is 5% and the elastic modulus is 69 GPa (10 Msi). 3A21-H16 has a density of 2.73 g/cm³ (0.0986 lb/in³), heavier than 61% of aluminum grades. It melts at 643°C (1,189 °F). H14 is the default condition FabDigit quotes; H16 is available on request or by drawing note.
Advantages
- Readily welded — 92/100, better than 95% of aluminum grades
- Good corrosion resistance — 72/100, better than 83% of aluminum grades
Limitations
- Difficult to machine — 44/100, worse than 76% of aluminum grades
- Hard to polish — 45/100, worse than 76% of aluminum grades
3A21-H16 properties
Typical room-temperature values for 3A21-H16; 12 are specific to this condition. Other listed values are 3A21 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
3A21-H16 has a density of 2.73 g/cm³ (0.0986 lb/in³), heavier than 61% of aluminum grades. It melts at 643°C (1,189 °F).
Mechanical10
3A21-H16 has a yield strength of 170 MPa (24.7 ksi) and a tensile strength of 180 MPa (26.1 ksi) — weaker than 56% of aluminum grades. Elongation at break is 5% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
3A21-H16 is rated for continuous service to 140°C (284 °F). It conducts heat at 155 W/m·K (89.6 BTU/hr·ft·°F), better than 71% of aluminum grades. Thermal expansion is 23.2 µm/m·K (12.9 µin/in·°F).
Electrical3
3A21-H16 conducts electricity at 40 % IACS, better than 72% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), better than 83% of aluminum grades.
Sustainability4
Producing a kilogram of 3A21-H16 takes about 200 MJ of energy and emits 13 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 35%.
Manufacturability7
3A21-H16's machinability is fair (44/100, worse than 76% of aluminum grades); weldability excellent (92/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 3A21-H16
Is 3A21 easy to machine?
Soft and gummy — use polished high-rake carbide, high speed, generous feed and lubricant to avoid built-up edge; H18 machines noticeably cleaner than O.
Can 3A21 be welded?
Excellent by TIG/MIG with ER1100 or ER4043 filler and by resistance/torch brazing; the HAZ softens to near-O strength, so design joints for annealed properties.
Can 3A21 be formed, bent or molded?
Outstanding deep drawing, spinning and roll forming in O/H2x tempers; anneal at 415 °C (air cool) between heavy draws; no heat-treat strengthening is possible.
What surface finishes work on 3A21?
Takes chemical conversion coating, paint and clear/protective anodize well, but the anodic film is grey-toned and non-uniform on bright-decorative work; polishes only to a satin lustre.
3A21 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 |
|---|---|---|
| SiGB/T 3190; some editions specify Si+Fe ≤ 0.7 | ≤ 0.6 | 0.25 |
| Fe | ≤ 0.7 | 0.4 |
| Cu | ≤ 0.2 | 0.05 |
| Mnmain strengthening/corrosion element | 1 – 1.6 | 1.3 |
| Mg | ≤ 0.05 | 0.02 |
| Zn | ≤ 0.1 | 0.03 |
| Tigrain refiner | ≤ 0.15 | 0.03 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
3A21-H16 — frequently asked
What is 3A21-H16 used for?
3A21-H16 is typically used for chemical equipment tanks, food processing vessels, heat exchanger tubing, sheet metal enclosures and kitchenware. In short: 3003-equivalent Al-Mn sheet; excellent weldability and formability; low strength, no heat treatment.
What is the yield strength of 3A21-H16?
3A21-H16 has a typical yield strength of 170 MPa (24.7 ksi) and a tensile strength of 180 MPa (26.1 ksi) — weaker than 56% of aluminum grades. Strength varies by condition: see the 10 listed tempers.
Is 3A21-H16 easy to machine?
Not especially — machinability is rated fair (44/100, worse than 76% of aluminum grades). Soft and gummy — use polished high-rake carbide, high speed, generous feed and lubricant to avoid built-up edge; H18 machines noticeably cleaner than O.
Can 3A21-H16 be welded?
Yes — weldability is rated excellent (92/100). Excellent by TIG/MIG with ER1100 or ER4043 filler and by resistance/torch brazing; the HAZ softens to near-O strength, so design joints for annealed properties.
What surface finishes work on 3A21-H16?
Takes chemical conversion coating, paint and clear/protective anodize well, but the anodic film is grey-toned and non-uniform on bright-decorative work; polishes only to a satin lustre.
Can 3A21-H16 be formed, bent or molded?
Outstanding deep drawing, spinning and roll forming in O/H2x tempers; anneal at 415 °C (air cool) between heavy draws; no heat-treat strengthening is possible.
What is the maximum service temperature of 3A21-H16?
3A21-H16 is rated for continuous use to about 140°C (284 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 3A21-H14 and 3A21-O?
H14 is the default condition — the default stocked sheet/coil condition: balanced strength, flatness and workability for panels, tanks and ducting. O: pick for maximum ductility: deep drawing, spinning, tube bending, complex-formed vessels. Yield strength is 145 MPa in H14 versus 42 MPa in O.
Sources
- ASTM B209 / B221 (3003 equivalent) — ASTM (2021)
- Aluminum Standards and Data (Teal Sheets) — The Aluminum Association (2015)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
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.