Aluminum 3B21-H16
Temper
GB 3B21
H16 = strain hardened, three-quarter hard
Use where flat strength and dent resistance dominate and only mild forming is required.
Values for the H16 condition
Other 3B21 tempers and conditions
3B21 is listed in 16 conditions; see the grade overview at 3B21.
Compare all 16 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for deep drawing, spinning, tight bends and any severe cold forming. | 52 | 130 | 26 | 30 HB | 42 % IACS |
Strain hardened from hot working only | Standard temper for thicker hot-rolled plate that will be welded or machined rather than cold formed. | 65 | 145 | 18 | 33 HB | 42 % IACS |
As fabricated | Mill-supplied hot-worked/extruded stock with no guaranteed mechanicals; buy only if you will heat treat, form or test yourself. | 65 | 140 | 18 | 30 HB | 42 % IACS |
Strain hardened and partially annealed, quarter hard | Same strength class as H12 but with restored ductility — use for tube bending and formed profiles. | 115 | 150 | 15 | 37 HB | 41 % IACS |
Strain hardened and stabilized, quarter hard | Stabilized temper (thermal treatment after rolling) for the Mg-bearing chemistry; use when long-term property stability matters. | 120 | 155 | 14 | 38 HB | 41 % IACS |
Strain hardened, quarter hard | Light work hardening when a little extra stiffness is needed but bending is still frequent. | 125 | 155 | 12 | 38 HB | 41 % IACS |
Strain hardened and partially annealed, half hard | Most common temper for formed architectural sheet and roll-formed panels needing H14 strength with better bend behaviour. | 140 | 170 | 10 | 43 HB | 40 % IACS |
Strain hardened and stabilized, half hard | Stabilized mid-strength sheet/plate for welded tanks and vessels held at mildly elevated temperature. | 145 | 175 | 10 | 44 HB | 40 % IACS |
H14Default Strain hardened, half hard | The default stocked sheet/coil temper: best balance of panel stiffness and roll-forming/bending ability. | 150 | 175 | 8 | 44 HB | 40 % IACS |
Strain hardened and partially annealed, three-quarter hard | High-strength strip that must still take a modest bend, e.g. clip and bracket stampings. | 165 | 195 | 6 | 49 HB | 40 % IACS |
Strain hardened and stabilized, three-quarter hard | Stabilized high-strength strip for lightly formed, dimensionally stable parts. | 170 | 200 | 6 | 50 HB | 40 % IACS |
H16This page Strain hardened, three-quarter hard | Use where flat strength and dent resistance dominate and only mild forming is required. | 175 | 200 | 5 | 50 HB | 40 % IACS |
Strain hardened and partially annealed, full hard | Full-hard strip with slightly better ductility than H18; niche stamping/spring-clip use. | 190 | 220 | 4 | 55 HB | 39.5 % IACS |
Strain hardened and stabilized, full hard | Highest stabilized strength; flat parts only, essentially no forming reserve. | 195 | 225 | 4 | 56 HB | 39.5 % IACS |
Strain hardened, full hard | Maximum strain-hardened strength for flat parts, shims and stamped blanks; bending must be generous-radius. | 200 | 225 | 4 | 56 HB | 40 % IACS |
Strain hardened, extra hard | Only for thin strip and foil where maximum as-rolled hardness is wanted; essentially non-formable. | 220 | 245 | 2 | 60 HB | 39 % IACS |
What is 3B21-H16?
3B21-H16 is 3B21 in the H16 temper — use where flat strength and dent resistance dominate and only mild forming is required. 3B21-H16 has a yield strength of 175 MPa (25.4 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 55% of aluminum grades. Elongation at break is 5% and the elastic modulus is 69 GPa (10 Msi). 3B21-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 — 88/100, better than 85% of aluminum grades
- Good corrosion resistance — 70/100, better than 79% of aluminum grades
- Forms and bends easily — 60/100, better than 77% of aluminum grades
Limitations
- Difficult to machine — 36/100, worse than 84% of aluminum grades
3B21-H16 properties
Typical room-temperature values for 3B21-H16; 10 are specific to this condition. Other listed values are 3B21 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
3B21-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
3B21-H16 has a yield strength of 175 MPa (25.4 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 55% of aluminum grades. Elongation at break is 5% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
3B21-H16 is rated for continuous service to 150°C (302 °F). It conducts heat at 157 W/m·K (90.7 BTU/hr·ft·°F), better than 73% of aluminum grades. Thermal expansion is 23.2 µm/m·K (12.9 µin/in·°F).
Electrical3
3B21-H16 conducts electricity at 40 % IACS, better than 72% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 79% of aluminum grades.
Sustainability4
Producing a kilogram of 3B21-H16 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 35%.
Manufacturability7
3B21-H16's machinability is fair (36/100, worse than 84% of aluminum grades); weldability excellent (88/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 3B21-H16
Is 3B21 easy to machine?
Soft and gummy: use sharp polished high-rake carbide, high speed, low feed and flood coolant/lubricant to avoid built-up edge; harder H16–H18 tempers give cleaner chips.
Can 3B21 be welded?
Excellent with GTAW/GMAW using ER4043 or ER5356 filler, and readily resistance-spot welded; the HAZ reverts toward O temper, so design joints for annealed strength.
Can 3B21 be formed, bent or molded?
Very good cold formability — O/H22/H24 tempers deep draw, roll-form and bend tightly; interstage anneal at 340–400 °C if severe multi-stage drawing is needed.
What surface finishes work on 3B21?
Takes clear/protective sulphuric anodize, chromate/chrome-free conversion coating, and coil paint/PVDF well; bright decorative anodizing is only fair because Mn dispersoids grey the film.
3B21 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 |
|---|---|---|
| Siimpurity limit; Si+Fe often jointly capped | ≤ 0.5 | 0.2 |
| Feimpurity limit | ≤ 0.5 | 0.3 |
| Cukept low for corrosion resistance | ≤ 0.1 | 0.03 |
| Mnprincipal strengthening/dispersoid element | 1 – 1.6 | 1.3 |
| Mgsmall deliberate addition — main difference vs 3A21 | 0.1 – 0.6 | 0.35 |
| Zn | ≤ 0.1 | — |
| Tigrain refiner residual | ≤ 0.15 | 0.03 |
| Others (each)total others ≤ 0.15 | ≤ 0.05 | — |
| Alremainder; confirm exact limits against the current GB/T 3190 edition and the mill certificate | balance | — |
3B21-H16 — frequently asked
What is 3B21-H16 used for?
3B21-H16 is typically used for architectural cladding, roofing and gutter sheet, general fabrication plate and corrosion-resistant panels. In short: stronger than 3A21 sheet; formable architectural alloy; weldable, non-heat-treatable.
What is the yield strength of 3B21-H16?
3B21-H16 has a typical yield strength of 175 MPa (25.4 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 55% of aluminum grades. Strength varies by condition: see the 16 listed tempers.
Is 3B21-H16 easy to machine?
Not especially — machinability is rated fair (36/100, worse than 84% of aluminum grades). Soft and gummy: use sharp polished high-rake carbide, high speed, low feed and flood coolant/lubricant to avoid built-up edge; harder H16–H18 tempers give cleaner chips.
Can 3B21-H16 be welded?
Yes — weldability is rated excellent (88/100). Excellent with GTAW/GMAW using ER4043 or ER5356 filler, and readily resistance-spot welded; the HAZ reverts toward O temper, so design joints for annealed strength.
What surface finishes work on 3B21-H16?
Takes clear/protective sulphuric anodize, chromate/chrome-free conversion coating, and coil paint/PVDF well; bright decorative anodizing is only fair because Mn dispersoids grey the film.
Can 3B21-H16 be formed, bent or molded?
Very good cold formability — O/H22/H24 tempers deep draw, roll-form and bend tightly; interstage anneal at 340–400 °C if severe multi-stage drawing is needed.
What is the maximum service temperature of 3B21-H16?
3B21-H16 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 3B21-H14 and 3B21-O?
H14 is the default condition — the default stocked sheet/coil temper: best balance of panel stiffness and roll-forming/bending ability. O: pick for deep drawing, spinning, tight bends and any severe cold forming. Yield strength is 150 MPa in H14 versus 52 MPa in O.
Sources
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys (3000 series Al-Mn data) — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials (aluminium alloys) — ASM International (2005)
- Aluminum Association Teal Sheets — Alloy and Temper Designations — The Aluminum Association (2018)
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.