Aluminum 393.0-T7
Temper
AA 393.0 · UNS A03930
T7 = solution heat treated and overaged (stabilized)
Choose when long-term dimensional stability and growth resistance at 250–300 °C outrank peak strength.
Values for the T7 condition
Other 393.0 tempers and conditions
393.0 is listed in 4 conditions; see the grade overview at 393.0.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Lowest-cost condition for wear parts where dimensional stability after machining is not critical. | 200 | 220 | 0.5 | 115 HB | 22 % IACS |
Cooled from hot working and artificially aged | Cheap stabilizing age used when distortion from solution treatment must be avoided. | 225 | 245 | 0.5 | 125 HB | 23 % IACS |
T7This page Solution heat treated and overaged (stabilized) | Choose when long-term dimensional stability and growth resistance at 250–300 °C outrank peak strength. | 230 | 250 | 1 | 120 HB | 26 % IACS |
T6Default Solution heat treated and artificially aged | Standard condition for high-output pistons: maximum room- and elevated-temperature strength with best wear resistance. | 275 | 290 | 0.7 | 140 HB | 24 % IACS |
What is 393.0-T7?
393.0-T7 is 393.0 in the T7 temper — choose when long-term dimensional stability and growth resistance at 250–300 °C outrank peak strength. 393.0-T7 has a yield strength of 230 MPa (33.4 ksi) and a tensile strength of 250 MPa (36.3 ksi) — stronger than 60% of aluminum grades. Elongation at break is 1% and the elastic modulus is 88 GPa (12.8 Msi). 393.0-T7 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 59% of aluminum grades. It melts at 555°C (1,031 °F). T6 is the default condition FabDigit quotes; T7 is available on request or by drawing note.
Advantages
- High service temperature — 300°C (572 °F), better than 99% of aluminum grades
- Stiff — 88 GPa (12.8 Msi), better than 98% of aluminum grades
Limitations
- Difficult to machine — 24/100, worse than 98% of aluminum grades
- Hard to polish — 35/100, worse than 98% of aluminum grades
- Low fracture toughness — 14 MPa·√m (12.7 ksi·√in), worse than 97% of aluminum grades
- Limited ductility — 1%, worse than 95% of aluminum grades
- Low electrical conductivity — 26 % IACS, worse than 90% of aluminum grades
393.0-T7 properties
Typical room-temperature values for 393.0-T7; 22 are specific to this condition. Other listed values are 393.0 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
393.0-T7 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 59% of aluminum grades. It melts at 555°C (1,031 °F).
Mechanical16
393.0-T7 has a yield strength of 230 MPa (33.4 ksi) and a tensile strength of 250 MPa (36.3 ksi) — stronger than 60% of aluminum grades. Elongation at break is 1% and the elastic modulus is 88 GPa (12.8 Msi).
Thermal6
393.0-T7 is rated for continuous service to 300°C (572 °F). It conducts heat at 138 W/m·K (79.7 BTU/hr·ft·°F), worse than 55% of aluminum grades. Thermal expansion is 15.8 µm/m·K (8.78 µin/in·°F).
Electrical3
393.0-T7 conducts electricity at 26 % IACS, worse than 90% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 58% of aluminum grades.
Sustainability4
Producing a kilogram of 393.0-T7 takes about 190 MJ of energy and emits 12 kg of CO₂ — less than 89% of aluminum grades. Typical recycled content is 30%.
Manufacturability8
393.0-T7's machinability is poor (24/100, worse than 98% of aluminum grades); weldability poor (28/100); formability not recommended (7/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 393.0-T7
Is 393.0 easy to machine?
Treat as an abrasive metal-matrix composite: PCD or CVD-diamond tooling, high speed / light feed, flood coolant; carbide life is measured in minutes.
Can 393.0 be welded?
Poor — fusion welding causes hot cracking and coarse Si; repair only by specialized TIG with 4047/4145 filler and preheat, or avoid entirely.
Can 393.0 be formed, bent or molded?
Permanent mold, low-pressure or squeeze casting with phosphorus refinement, ~750–800 °C pour and controlled cooling to keep primary Si fine and evenly dispersed; not a die-casting-friendly or wrought alloy.
What surface finishes work on 393.0?
Hard anodize gives thin dark films only; ring grooves are usually hard-anodized or Ni-plated, skirts tin-plated or graphite/moly coated for scuff resistance.
393.0 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 |
|---|---|---|
| Siprimary Si; P-refined for fine particle size | 21 – 23 | 22 |
| Cu | 0.7 – 1.1 | 0.9 |
| Mg | 0.7 – 1.3 | 1 |
| Nielevated-temperature aluminides | 2 – 2.5 | 2.2 |
| Fe | ≤ 1.3 | — |
| Mn | ≤ 0.1 | — |
| Cr | ≤ 0.1 | — |
| Zn | ≤ 0.1 | — |
| Ti | 0.1 – 0.2 | 0.15 |
| Others (each)each | ≤ 0.05 | — |
| Others (total)total | ≤ 0.15 | — |
| Al | balance | — |
393.0-T7 — frequently asked
What is 393.0-T7 used for?
393.0-T7 is typically used for performance engine pistons, cylinder liners and wear plates. In short: lowest-expansion cast aluminum; highest wear resistance; needs diamond tooling.
What is the yield strength of 393.0-T7?
393.0-T7 has a typical yield strength of 230 MPa (33.4 ksi) and a tensile strength of 250 MPa (36.3 ksi) — stronger than 60% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is 393.0-T7 easy to machine?
Not especially — machinability is rated poor (24/100, worse than 98% of aluminum grades). Treat as an abrasive metal-matrix composite: PCD or CVD-diamond tooling, high speed / light feed, flood coolant; carbide life is measured in minutes.
Can 393.0-T7 be welded?
Not readily — weldability is rated poor (28/100). Poor — fusion welding causes hot cracking and coarse Si; repair only by specialized TIG with 4047/4145 filler and preheat, or avoid entirely.
What surface finishes work on 393.0-T7?
Hard anodize gives thin dark films only; ring grooves are usually hard-anodized or Ni-plated, skirts tin-plated or graphite/moly coated for scuff resistance.
Can 393.0-T7 be formed, bent or molded?
Permanent mold, low-pressure or squeeze casting with phosphorus refinement, ~750–800 °C pour and controlled cooling to keep primary Si fine and evenly dispersed; not a die-casting-friendly or wrought alloy.
What is the maximum service temperature of 393.0-T7?
393.0-T7 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 393.0-T6 and 393.0-F?
T6 is the default condition — standard condition for high-output pistons: maximum room- and elevated-temperature strength with best wear resistance. F: lowest-cost condition for wear parts where dimensional stability after machining is not critical. Yield strength is 275 MPa in T6 versus 200 MPa in F.
Sources
- Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot (Pink Sheets) — The Aluminum Association (2018)
- ASTM B108 / B26 — Aluminum-Alloy Permanent Mold and Sand Castings — ASTM International (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
- ASM Handbook Vol. 15 — Casting — ASM International (2008)
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.