Aluminum 6951-H24
Temper
AA 6951 · UNS A96951 · EN AW-6951
H24 = strain hardened and partially annealed, half hard
Half-hard strength with better bend ductility than H14 — preferred for folded (B-type) brazed tube.
Values for the H24 condition
Other 6951 tempers and conditions
6951 is listed in 12 conditions; see the grade overview at 6951.
Compare all 12 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ODefault Annealed | Standard condition for clad brazing sheet that will be roll-formed into tubes/fins and then furnace brazed. | 41 | 110 | 30 | 28 HB | 50 % IACS |
As-brazed (post-CAB, naturally aged core) | The real in-service state of radiator/condenser tubes: core recrystallised by the 595–605 °C braze cycle, then naturally aged for weeks. | 70 | 165 | 20 | 45 HB | 46 % IACS |
Strain hardened, quarter hard | Light temper rolling when slightly stiffer strip is needed but deep forming is still required. | 105 | 130 | 12 | 38 HB | 50 % IACS |
Solution heat treated by the user and naturally aged | Applies when the fabricator (not the mill) solution treats formed parts, e.g. after brazing and quench. | 110 | 205 | 22 | 58 HB | 44 % IACS |
H24This page Strain hardened and partially annealed, half hard | Half-hard strength with better bend ductility than H14 — preferred for folded (B-type) brazed tube. | 120 | 150 | 10 | 44 HB | 50 % IACS |
Solution heat treated and naturally aged | Formable but pre-strengthened condition; also approximates the state of brazed parts after natural aging. | 125 | 220 | 20 | 62 HB | 43 % IACS |
Strain hardened, half hard | Common as-rolled coil temper for high-speed fin mills and welded-tube stock. | 130 | 150 | 8 | 45 HB | 50 % IACS |
Strain hardened, three-quarter hard | Stiffer strip for narrow fin stock where limited bending is acceptable. | 160 | 175 | 5 | 52 HB | 50 % IACS |
Cooled from hot working and artificially aged | Used when the braze-furnace exit cooling is fast enough to act as a quench, followed by a low-temperature age. | 170 | 210 | 12 | 68 HB | 46 % IACS |
Strain hardened, full hard | Maximum cold-worked strength; used where the strip is only slit and corrugated, not deep drawn. | 185 | 200 | 3 | 58 HB | 50 % IACS |
T6, heat treated by the user | Same target properties as T6 but achieved by heat treating O/H-temper material after fabrication or brazing. | 215 | 260 | 12 | 80 HB | 45 % IACS |
Solution heat treated and artificially aged | Peak-strength condition for structural sheet or for brazed assemblies that are re-solution treated and aged. | 230 | 270 | 13 | 82 HB | 45 % IACS |
What is 6951-H24?
6951-H24 is 6951 in the H24 temper — half-hard strength with better bend ductility than H14 — preferred for folded (B-type) brazed tube. 6951-H24 has a yield strength of 120 MPa (17.4 ksi) and a tensile strength of 150 MPa (21.8 ksi) — weaker than 77% of aluminum grades. Elongation at break is 10% and the elastic modulus is 69 GPa (10 Msi). 6951-H24 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 59% of aluminum grades. It melts at 616°C (1,141 °F). O is the default condition FabDigit quotes; H24 is available on request or by drawing note.
Advantages
- Conducts heat well — 199 W/m·K (115 BTU/hr·ft·°F), better than 90% of aluminum grades
- High electrical conductivity — 50 % IACS, better than 90% of aluminum grades
- Forms and bends easily — 75/100, better than 86% of aluminum grades
Limitations
- Low strength — 120 MPa (17.4 ksi), worse than 77% of aluminum grades
- Difficult to machine — 44/100, worse than 76% of aluminum grades
6951-H24 properties
Typical room-temperature values for 6951-H24; 20 are specific to this condition. Other listed values are 6951 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
6951-H24 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 59% of aluminum grades. It melts at 616°C (1,141 °F).
Mechanical10
6951-H24 has a yield strength of 120 MPa (17.4 ksi) and a tensile strength of 150 MPa (21.8 ksi) — weaker than 77% of aluminum grades. Elongation at break is 10% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
6951-H24 is rated for continuous service to 150°C (302 °F). It conducts heat at 199 W/m·K (115 BTU/hr·ft·°F), better than 90% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
6951-H24 conducts electricity at 50 % IACS, better than 90% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), better than 57% of aluminum grades.
Sustainability4
Producing a kilogram of 6951-H24 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 30%.
Manufacturability8
6951-H24's machinability is fair (44/100, worse than 76% of aluminum grades); weldability very good (72/100); formability very good (75/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 6951-H24
Is 6951 easy to machine?
Soft and gummy in O/T4 — use polished high-rake carbide, high speed and flood or MQL lubricant; T6 chips break far better.
Can 6951 be welded?
Readily GTAW/GMAW welded with 4043 filler (4047 for the clad side); avoid 5000-series filler on the Al-Si clad layer and expect strength loss in the HAZ of aged tempers.
Can 6951 be formed, bent or molded?
Excellent roll forming, fin corrugating and tube seaming in O/H24; keep bend radii ≥1t in H18 and re-anneal or use T4 for deep draws.
What surface finishes work on 6951?
Designed for CAB (Nocolok flux) or vacuum brazing at 590–605 °C; for corrosion protection use Zn arc-spray or chromate-free conversion coat plus e-coat rather than decorative anodizing, since the clad Al-Si layer anodizes unevenly.
6951 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 |
|---|---|---|
| Si | 0.2 – 0.5 | 0.35 |
| Feimpurity limit | ≤ 0.8 | 0.35 |
| Cu | 0.15 – 0.4 | 0.25 |
| Mn | ≤ 0.1 | 0.03 |
| Mg | 0.4 – 0.8 | 0.6 |
| Zn | ≤ 0.2 | 0.05 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Alremainder, ~98.3 % nominal | balance | — |
6951-H24 — frequently asked
What is 6951-H24 used for?
6951-H24 is typically used for automotive radiators, HVAC heat exchangers and brazed fin/tube assemblies. In short: brazing-sheet core alloy; highest-formability 6000 series; heat-exchanger fin stock.
What is the yield strength of 6951-H24?
6951-H24 has a typical yield strength of 120 MPa (17.4 ksi) and a tensile strength of 150 MPa (21.8 ksi) — weaker than 77% of aluminum grades. Strength varies by condition: see the 12 listed tempers.
Is 6951-H24 easy to machine?
Not especially — machinability is rated fair (44/100, worse than 76% of aluminum grades). Soft and gummy in O/T4 — use polished high-rake carbide, high speed and flood or MQL lubricant; T6 chips break far better.
Can 6951-H24 be welded?
Yes — weldability is rated very good (72/100). Readily GTAW/GMAW welded with 4043 filler (4047 for the clad side); avoid 5000-series filler on the Al-Si clad layer and expect strength loss in the HAZ of aged tempers.
What surface finishes work on 6951-H24?
Designed for CAB (Nocolok flux) or vacuum brazing at 590–605 °C; for corrosion protection use Zn arc-spray or chromate-free conversion coat plus e-coat rather than decorative anodizing, since the clad Al-Si layer anodizes unevenly.
Can 6951-H24 be formed, bent or molded?
Excellent roll forming, fin corrugating and tube seaming in O/H24; keep bend radii ≥1t in H18 and re-anneal or use T4 for deep draws.
What is the maximum service temperature of 6951-H24?
6951-H24 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 6951-O and 6951-T6?
O is the default condition — standard condition for clad brazing sheet that will be roll-formed into tubes/fins and then furnace brazed. T6: peak-strength condition for structural sheet or for brazed assemblies that are re-solution treated and aged. Yield strength is 41 MPa in O versus 230 MPa in T6.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASTM B209 / B209M — Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate — ASTM International (2021)
- EN 573-3 / EN 485-2 — Aluminium and aluminium alloys: chemical composition and mechanical properties of sheet and strip — CEN (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys (brazing sheet chapter) — ASM International (1993)
- Aluminium brazing sheet product data (clad 4343/4045 on 6951/3003 core) — Rolled-product mills (e.g. Novelis / Granges / Constellium class data) (2022)
- MatWeb wrought aluminum 6951 temper property listings — MatWeb LLC (2023)
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.