Aluminum 3203 · temper
Aluminum 3203-H18
Properties of the H18 condition, compared with the other 3203 tempers.
Maximum work-hardened strength for flat blanks, fin stock and thin strip with minimal forming.
What is 3203-H18?
3203-H18 is 3203 in the H18 temper — maximum work-hardened strength for flat blanks, fin stock and thin strip with minimal forming. 3203-H18 has a yield strength of 186 MPa (27 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 53% of aluminum grades. Elongation at break is 4% and the elastic modulus is 69 GPa (10 Msi). 3203-H18 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; H18 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
Limitations
- Hard to polish — 45/100, worse than 76% of aluminum grades
3203-H18 properties
Typical room-temperature values for 3203-H18 — 10 properties are specific to this condition; the rest are grade-level values shared by every 3203 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
3203-H18 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
3203-H18 has a yield strength of 186 MPa (27 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 53% of aluminum grades. Elongation at break is 4% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
3203-H18 is rated for continuous service to 150°C (302 °F). It conducts heat at 154 W/m·K (89 BTU/hr·ft·°F), better than 68% of aluminum grades. Thermal expansion is 23.2 µm/m·K (12.9 µin/in·°F).
Electrical3
3203-H18 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 3203-H18 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability7
3203-H18's machinability is good (55/100, worse than 58% of aluminum grades); weldability excellent (88/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 3203 tempers and conditions
3203 is also supplied in 12 other conditions. The full side-by-side table is on the 3203 overview.
- H14DefaultThe general-purpose stocked sheet/tube temper: good strength–formability balance for heat-exchanger tube, panels and fin stock.145 MPa yield · 40 HB
- H18Maximum work-hardened strength for flat blanks, fin stock and thin strip with minimal forming.186 MPa yield · 55 HB
- H16Higher-strength strip for lightly formed parts, shutters and tube where stiffness matters more than bendability.172 MPa yield · 47 HB
- H12Light work hardening for roll-formed and moderately bent parts needing a bit more strength than O.124 MPa yield · 35 HB
- OPick for deep drawing, tight bending, fin-forming and for brazing-sheet core where post-braze softness is accepted.42 MPa yield · 28 HB
Working with 3203-H18
Is 3203 easy to machine?
Soft and gummy — use polished high-rake carbide, high surface speed, sharp tools and flood coolant to avoid built-up edge; harder H16/H18 tempers cut cleaner.
Can 3203 be welded?
Readily GTAW/GMAW welded with 1100 or 4043 filler (4047 for brazing-sheet assemblies); weld zone reverts to O-temper strength.
Can 3203 be formed, bent or molded?
Excellent cold formability in O/H22/H24 — deep drawing, fin corrugation and tube rolling are routine; allow larger bend radii in H16–H19.
What surface finishes work on 3203?
Takes chromate/no-chrome conversion coatings and paint well; clear anodize is protective but grey-toned, so use for functional rather than decorative finishes.
3203 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 |
|---|---|---|
| SiSi+Fe controlled in fin stock | ≤ 0.6 | 0.25 |
| Fe | ≤ 0.7 | 0.45 |
| Cukey difference vs 3003 (Cu 0.05–0.20) | ≤ 0.05 | 0.02 |
| Mnprimary strengthening/dispersoid element | 1 – 1.5 | 1.2 |
| Zn | ≤ 0.1 | 0.03 |
| Tigrain refiner (where registered) | ≤ 0.1 | 0.02 |
| Other (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
3203-H18 — frequently asked
What is 3203-H18 used for?
3203-H18 is typically used for brazed heat exchanger fin stock, heat exchanger tube stock, brazing sheet core, radiator and condenser assemblies, cooking utensils and roofing and siding sheet. In short: international 3003 equivalent; general purpose.
What is the yield strength of 3203-H18?
3203-H18 has a typical yield strength of 186 MPa (27 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 53% of aluminum grades. Strength varies by condition: see the 13 listed tempers.
Is 3203-H18 easy to machine?
Reasonably — machinability is rated good (55/100, worse than 58% of aluminum grades). Soft and gummy — use polished high-rake carbide, high surface speed, sharp tools and flood coolant to avoid built-up edge; harder H16/H18 tempers cut cleaner.
Can 3203-H18 be welded?
Yes — weldability is rated excellent (88/100). Readily GTAW/GMAW welded with 1100 or 4043 filler (4047 for brazing-sheet assemblies); weld zone reverts to O-temper strength.
What surface finishes work on 3203-H18?
Takes chromate/no-chrome conversion coatings and paint well; clear anodize is protective but grey-toned, so use for functional rather than decorative finishes.
Can 3203-H18 be formed, bent or molded?
Excellent cold formability in O/H22/H24 — deep drawing, fin corrugation and tube rolling are routine; allow larger bend radii in H16–H19.
What is the maximum service temperature of 3203-H18?
3203-H18 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 3203-H14 and 3203-O?
H14 is the default condition — the general-purpose stocked sheet/tube temper: good strength–formability balance for heat-exchanger tube, panels and fin stock. O: pick for deep drawing, tight bending, fin-forming and for brazing-sheet core where post-braze softness is accepted. Yield strength is 145 MPa in H14 versus 42 MPa in O.
Can FabDigit make parts in 3203-H18?
Yes — 3203-H18 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)
- EN 573-3 / EN 485-2 — Aluminium and aluminium alloys: chemical composition and mechanical properties of sheet, strip and plate — CEN (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (3003/3xxx data) — ASM International (1990)
- ASTM B209 — Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate — ASTM International (2021)
- Heat-exchanger tube and fin stock alloy datasheets (3003/3203 class) — Constellium / Novelis (2022)
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.