4343 (BAlSi-2, AlSi7.5) Aluminum
4343 aluminum is a 4000-series aluminum alloy. The main alloying addition is silicon. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. 4343 is the Aluminum Association (AA) designation for this material. In European standards, it will be given as EN AW-4343. BAlSi-2 is the AWS designation. Additionally, the EN chemical designation is AlSi7,5. And the UNS number is A94343.
It originally received its standard designation in 1954.
The graph bars on the material properties cards below compare 4343 aluminum to: 4000-series alloys (top), all aluminum alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
71 GPa 10 x 106 psi
Elongation at Break
4.4 %
Fatigue Strength
45 MPa 6.5 x 103 psi
Poisson's Ratio
0.33
Shear Modulus
27 GPa 3.9 x 106 psi
Shear Strength
64 MPa 9.2 x 103 psi
Tensile Strength: Ultimate (UTS)
110 MPa 16 x 103 psi
Tensile Strength: Yield (Proof)
62 MPa 8.9 x 103 psi
Thermal Properties
Brazing Temperature
600 to 620 °C 1110 to 1150 °F
Latent Heat of Fusion
510 J/g
Maximum Temperature: Mechanical
160 °C 320 °F
Melting Completion (Liquidus)
620 °C 1140 °F
Melting Onset (Solidus)
580 °C 1070 °F
Specific Heat Capacity
900 J/kg-K 0.22 BTU/lb-°F
Thermal Conductivity
180 W/m-K 100 BTU/h-ft-°F
Thermal Expansion
22 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
44 % IACS
Electrical Conductivity: Equal Weight (Specific)
150 % IACS
Otherwise Unclassified Properties
Base Metal Price
9.5 % relative
Density
2.6 g/cm3 160 lb/ft3
Embodied Carbon
7.9 kg CO2/kg material
Embodied Energy
150 MJ/kg 64 x 103 BTU/lb
Embodied Water
1100 L/kg 130 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
4.1 MJ/m3
Resilience: Unit (Modulus of Resilience)
27 kJ/m3
Stiffness to Weight: Axial
15 points
Stiffness to Weight: Bending
53 points
Strength to Weight: Axial
12 points
Strength to Weight: Bending
20 points
Thermal Diffusivity
77 mm2/s
Thermal Shock Resistance
5.2 points
Alloy Composition
Among wrought aluminum alloys, the composition of 4343 aluminum is notable for containing a comparatively high amount of silicon (Si). Silicon is used to increase strength at the expense of ductility. It also lowers the melting temperature and raises the fluidity of the alloy.
| Al | 90.3 to 93.2 | |
| Si | 6.8 to 8.2 | |
| Fe | 0 to 0.8 | |
| Cu | 0 to 0.25 | |
| Zn | 0 to 0.2 | |
| Mn | 0 to 0.1 | |
| res. | 0 to 0.15 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
AWS A5.8: Specification for Filler Metals for Brazing and Braze Welding
Aluminum Standards and Data, Aluminum Association Inc., 2013
EN 573-3: Aluminium and aluminium alloys. Chemical composition and form of wrought products. Chemical composition and form of products
Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993