Aluminum 3105 · temper
Aluminum 3105-O
Properties of the O condition, compared with the other 3105 tempers.
Pick for deep drawing, spinning or severe roll forming where maximum ductility is required.
What is 3105-O?
3105-O is 3105 in the O temper — pick for deep drawing, spinning or severe roll forming where maximum ductility is required. 3105-O has a yield strength of 55 MPa (7.98 ksi) and a tensile strength of 115 MPa (16.7 ksi) — weaker than 94% of aluminum grades. Elongation at break is 24% and the elastic modulus is 69 GPa (10 Msi). 3105-O has a density of 2.72 g/cm³ (0.0983 lb/in³), heavier than 57% of aluminum grades. It melts at 635°C (1,175 °F).
Advantages
- Forms and bends easily — 95/100, better than 96% of aluminum grades
- Ductile — tolerates forming and impact — 24%, better than 92% of aluminum grades
- High service temperature — 200°C (392 °F), better than 90% of aluminum grades
- Conducts heat well — 180 W/m·K (104 BTU/hr·ft·°F), better than 87% of aluminum grades
- High electrical conductivity — 43 % IACS, better than 83% of aluminum grades
Limitations
- Low strength — 55 MPa (7.98 ksi), worse than 94% of aluminum grades
- Difficult to machine — 30/100, worse than 91% of aluminum grades
- Hard to polish — 45/100, worse than 76% of aluminum grades
3105-O properties
Typical room-temperature values for 3105-O — 10 properties are specific to this condition; the rest are grade-level values shared by every 3105 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
3105-O has a density of 2.72 g/cm³ (0.0983 lb/in³), heavier than 57% of aluminum grades. It melts at 635°C (1,175 °F).
Mechanical10
3105-O has a yield strength of 55 MPa (7.98 ksi) and a tensile strength of 115 MPa (16.7 ksi) — weaker than 94% of aluminum grades. Elongation at break is 24% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
3105-O is rated for continuous service to 200°C (392 °F). It conducts heat at 180 W/m·K (104 BTU/hr·ft·°F), better than 87% of aluminum grades. Thermal expansion is 23.6 µm/m·K (13.1 µin/in·°F).
Electrical3
3105-O conducts electricity at 43 % IACS, better than 83% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 75% of aluminum grades.
Sustainability4
Producing a kilogram of 3105-O takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 40%.
Manufacturability7
3105-O's machinability is poor (30/100, worse than 91% of aluminum grades); weldability excellent (85/100); formability excellent (95/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 3105 tempers and conditions
3105 is also supplied in 13 other conditions. The full side-by-side table is on the 3105 overview.
- H19Extra-hard cold-rolled 3105 above full-hard H18 — maximum strength and springiness with minimal ductility, used for thin coil/fin and roll-formed profiles.215 MPa yield · 63 HB
- H25The classic North-American 3105 siding/gutter/trim temper — best balance of strength, roll formability and paint-line behaviour.160 MPa yield · 48 HB
- H14General-purpose half-hard sheet for stamped covers, trim and formed panels.150 MPa yield · 46 HB
- OPick for deep drawing, spinning or severe roll forming where maximum ductility is required.55 MPa yield · 28 HB
- H111Near-annealed 3105 sheet with only incidental work hardening from flattening/handling — softest usable formable temper with high ductility.55 MPa yield · 33 HB
Working with 3105-O
Is 3105 easy to machine?
Soft and gummy — use polished high-rake carbide, high surface speed and flood lubrication to avoid built-up edge; blanking and shearing are preferred over milling for thin coil.
Can 3105 be welded?
Readily GTAW/GMAW/resistance welded with 4043 or 5356 filler (5356 for better colour match after anodizing); HAZ reverts toward O strength, so joints lose H-temper properties.
Can 3105 be formed, bent or molded?
Excellent roll forming, bending and stamping in O/H2x tempers; H14–H18 need generous bend radii and grain-direction control to avoid edge cracking.
What surface finishes work on 3105?
Ideal substrate for coil coating and PVDF/polyester paint after chromate-free pretreatment; clear anodizing gives a dull grey, so anodize only for protection, not appearance.
3105 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 | ≤ 0.6 | 0.3 |
| Fe | ≤ 0.7 | 0.45 |
| Cu | ≤ 0.3 | 0.1 |
| Mn | 0.3 – 0.8 | 0.55 |
| Mg | 0.2 – 0.8 | 0.5 |
| Cr | ≤ 0.2 | 0.05 |
| Zn | ≤ 0.4 | 0.1 |
| Ti | ≤ 0.1 | 0.02 |
| Others (each)0.15 total | ≤ 0.05 | — |
| Al | balance | — |
3105-O — frequently asked
What is 3105-O used for?
3105-O is typically used for roofing panels, siding and sign blanks. In short: budget-friendly; easy shaping.
What is the yield strength of 3105-O?
3105-O has a typical yield strength of 55 MPa (7.98 ksi) and a tensile strength of 115 MPa (16.7 ksi) — weaker than 94% of aluminum grades. Strength varies by condition: see the 14 listed tempers.
Is 3105-O easy to machine?
Not especially — machinability is rated poor (30/100, worse than 91% of aluminum grades). Soft and gummy — use polished high-rake carbide, high surface speed and flood lubrication to avoid built-up edge; blanking and shearing are preferred over milling for thin coil.
Can 3105-O be welded?
Yes — weldability is rated excellent (85/100). Readily GTAW/GMAW/resistance welded with 4043 or 5356 filler (5356 for better colour match after anodizing); HAZ reverts toward O strength, so joints lose H-temper properties.
What surface finishes work on 3105-O?
Ideal substrate for coil coating and PVDF/polyester paint after chromate-free pretreatment; clear anodizing gives a dull grey, so anodize only for protection, not appearance.
Can 3105-O be formed, bent or molded?
Excellent roll forming, bending and stamping in O/H2x tempers; H14–H18 need generous bend radii and grain-direction control to avoid edge cracking.
What is the maximum service temperature of 3105-O?
3105-O is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 3105-O?
Yes — 3105-O is available for sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASTM B209 / B209M — Aluminum and Aluminum-Alloy Sheet and Plate — ASTM International (2021)
- EN 485-2 — Aluminium and aluminium alloys, sheet, strip and plate: mechanical properties — CEN (2016)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Aluminum Design Manual — The Aluminum Association (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.