Aluminum 1370 · temper
Aluminum 1370-O
Properties of the O condition, compared with the other 1370 tempers.
Pick for maximum conductivity, flexibility and deep-forming: flexible cable, winding strip, foil and formed busbar.
What is 1370-O?
1370-O is 1370 in the O temper — pick for maximum conductivity, flexibility and deep-forming: flexible cable, winding strip, foil and formed busbar. 1370-O has a yield strength of 25 MPa (3.63 ksi) and a tensile strength of 70 MPa (10.2 ksi) — weaker than 98% of aluminum grades. Elongation at break is 35% and the elastic modulus is 69 GPa (10 Msi). 1370-O has a density of 2.71 g/cm³ (0.0977 lb/in³), lighter than 54% of aluminum grades. It melts at 646°C (1,195 °F).
Advantages
- Conducts heat well — 236 W/m·K (136.4 BTU/hr·ft·°F), better than 100% of aluminum grades
- High electrical conductivity — 62.3 % IACS, better than 99% of aluminum grades
- Forms and bends easily — 98/100, better than 98% of aluminum grades
- Ductile — tolerates forming and impact — 35%, better than 97% of aluminum grades
- Polishes to a fine finish — 85/100, better than 96% of aluminum grades
Limitations
- Low strength — 25 MPa (3.63 ksi), worse than 98% of aluminum grades
- Difficult to machine — 25/100, worse than 96% of aluminum grades
1370-O properties
Typical room-temperature values for 1370-O — 13 properties are specific to this condition; the rest are grade-level values shared by every 1370 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
1370-O has a density of 2.71 g/cm³ (0.0977 lb/in³), lighter than 54% of aluminum grades. It melts at 646°C (1,195 °F).
Mechanical10
1370-O has a yield strength of 25 MPa (3.63 ksi) and a tensile strength of 70 MPa (10.2 ksi) — weaker than 98% of aluminum grades. Elongation at break is 35% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
1370-O is rated for continuous service to 150°C (302 °F). It conducts heat at 236 W/m·K (136.4 BTU/hr·ft·°F), better than 100% of aluminum grades. Thermal expansion is 23.6 µm/m·K (13.1 µin/in·°F).
Electrical3
1370-O conducts electricity at 62.3 % IACS, better than 99% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 79% of aluminum grades.
Sustainability4
Producing a kilogram of 1370-O takes about 210 MJ of energy and emits 12.5 kg of CO₂ — more than 88% of aluminum grades. Typical recycled content is 5%.
Manufacturability7
1370-O's machinability is poor (25/100, worse than 96% of aluminum grades); weldability excellent (92/100); formability excellent (98/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 1370 tempers and conditions
1370 is also supplied in 6 other conditions. The full side-by-side table is on the 1370 overview.
- H19Standard hard-drawn conductor wire/strand: highest strength for overhead and stranded cable, but limited to ~90 °C continuous.155 MPa yield · 40 HB
- OPick for maximum conductivity, flexibility and deep-forming: flexible cable, winding strip, foil and formed busbar.25 MPa yield · 20 HB
Working with 1370-O
Is 1370 easy to machine?
Soft and gummy — use polished high-rake carbide, high speed, low feed pressure and flood lubricant to avoid built-up edge and smearing; not a screw-machine material.
Can 1370 be welded?
Excellent with TIG/MIG using 1100 or 1188 filler, or by cold/friction/ultrasonic and exothermic (Cadweld) methods for conductors; hard tempers recrystallize and lose strength in the HAZ.
Can 1370 be formed, bent or molded?
Outstanding cold formability in O temper (deep drawing, foil rolling, wire drawing with 10–20 % reductions); anneal 340–410 °C to reset work hardening.
What surface finishes work on 1370?
Takes bright clear or hard anodizing very well; for electrical joints prefer tin or silver plating and abrasive cleaning plus joint compound rather than an insulating anodic film.
1370 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.
| Element | Spec limit (wt %) |
|---|---|
| Si | ≤ 0.1 |
| Fe | ≤ 0.25 |
| Cu | ≤ 0.02 |
| Mn | ≤ 0.01 |
| Mg | ≤ 0.02 |
| Cr | ≤ 0.01 |
| Zn | ≤ 0.04 |
| B | ≤ 0.02 |
| Ga | ≤ 0.03 |
| V+Ticombined max (conductivity-critical elements) | ≤ 0.02 |
| Others (each)each | ≤ 0.01 |
| Almin 99.70 %; minimum volume conductivity ≈61 %IACS (hard drawn) / 62 %IACS (annealed) | ≥ 99.7 (balance) |
1370-O — frequently asked
What is 1370-O used for?
1370-O is typically used for drawn conductor wire, stranded power cable conductors, busbar, transformer winding strip, motor and coil winding strip and extruded conductor rod. In short: high-conductivity wire; drawn rod.
What is the yield strength of 1370-O?
1370-O has a typical yield strength of 25 MPa (3.63 ksi) and a tensile strength of 70 MPa (10.2 ksi) — weaker than 98% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is 1370-O easy to machine?
Not especially — machinability is rated poor (25/100, worse than 96% of aluminum grades). Soft and gummy — use polished high-rake carbide, high speed, low feed pressure and flood lubricant to avoid built-up edge and smearing; not a screw-machine material.
Can 1370-O be welded?
Yes — weldability is rated excellent (92/100). Excellent with TIG/MIG using 1100 or 1188 filler, or by cold/friction/ultrasonic and exothermic (Cadweld) methods for conductors; hard tempers recrystallize and lose strength in the HAZ.
What surface finishes work on 1370-O?
Takes bright clear or hard anodizing very well; for electrical joints prefer tin or silver plating and abrasive cleaning plus joint compound rather than an insulating anodic film.
Can 1370-O be formed, bent or molded?
Outstanding cold formability in O temper (deep drawing, foil rolling, wire drawing with 10–20 % reductions); anneal 340–410 °C to reset work hardening.
What is the maximum service temperature of 1370-O?
1370-O 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.
Can FabDigit make parts in 1370-O?
Yes — 1370-O is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- EN 573-3 — Aluminium and aluminium alloys, chemical composition (EN AW-1370 / EAl99.7) — CEN (2019)
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- EN 1715-2 — Aluminium and aluminium alloys, drawing stock (wire) for electrical purposes — CEN (2010)
- IEC 60889 — Hard-drawn aluminium wire for overhead line conductors — IEC (1987)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (1xxx EC grades) — 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.