Precious Metal Dental Gold Type I-AC (Spheroidize annealed)
Heat-treated state · default condition
ASTM ADA Spec No.5 Type I · ISO 1562 Type 1
Standard condition of a lost-wax cast inlay; adequate strength with full burnishability.
Values for the AC condition
Other Dental Gold Type I tempers and conditions
Dental Gold Type I is listed in 3 conditions; see the grade overview at Dental Gold Type I.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Softened / homogenised | Pick when maximum ductility for margin burnishing and stress-free adaptation is wanted. | 80 | 230 | 35 | 52 HB | 24 % IACS |
ACDefaultThis page Spheroidize annealed | Standard condition of a lost-wax cast inlay; adequate strength with full burnishability. | 90 | 250 | 30 | 60 HB | 25 % IACS |
Cold worked | Condition of the burnished margin or of drawn wire/foil forms; strength raised at the cost of ductility. | 180 | 300 | 8 | 90 HB | 24 % IACS |
What is Dental Gold Type I-AC?
Dental Gold Type I-AC is Dental Gold Type I heat treated to AC — standard condition of a lost-wax cast inlay; adequate strength with full burnishability. Dental Gold Type I-AC has a yield strength of 90 MPa (13.1 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 86% of precious metal grades. Elongation at break is 30% and the elastic modulus is 85 GPa (12.3 Msi). Dental Gold Type I-AC has a density of 17.2 g/cm³ (0.621 lb/in³), heavier than 86% of precious metal grades. It melts at 935°C (1,715 °F).
Advantages
- Polishes to a fine finish — 98/100, better than 98% of precious metal grades
- Forms and bends easily — 96/100, better than 95% of precious metal grades
- Good corrosion resistance — 96/100, better than 85% of precious metal grades
Limitations
- Low strength — 90 MPa (13.1 ksi), worse than 86% of precious metal grades
- Heavy — 17.2 g/cm³ (0.621 lb/in³), worse than 86% of precious metal grades
- High embodied carbon — 13,000 kg CO₂/kg, worse than 81% of precious metal grades
Dental Gold Type I-AC properties
Typical room-temperature values for Dental Gold Type I-AC; 18 are specific to this condition. Other listed values are Dental Gold Type I reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
Dental Gold Type I-AC has a density of 17.2 g/cm³ (0.621 lb/in³), heavier than 86% of precious metal grades. It melts at 935°C (1,715 °F).
Mechanical12
Dental Gold Type I-AC has a yield strength of 90 MPa (13.1 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 86% of precious metal grades. Elongation at break is 30% and the elastic modulus is 85 GPa (12.3 Msi).
Thermal6
Dental Gold Type I-AC is rated for continuous service to 300°C (572 °F). It conducts heat at 115 W/m·K (66.4 BTU/hr·ft·°F), better than 61% of precious metal grades. Thermal expansion is 16 µm/m·K (8.89 µin/in·°F).
Electrical3
Dental Gold Type I-AC conducts electricity at 25 % IACS, better than 64% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (96/100), better than 85% of precious metal grades.
Sustainability4
Producing a kilogram of Dental Gold Type I-AC takes about 190,000 MJ of energy and emits 13,000 kg of CO₂ — more than 81% of precious metal grades. Typical recycled content is 60%.
Manufacturability8
Dental Gold Type I-AC's machinability is fair (40/100, worse than 60% of precious metal grades); weldability good (60/100); formability excellent (96/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Dental Gold Type I-AC
Is Dental Gold Type I easy to machine?
Very gummy and smearing — use sharp, high-rake carbide or HSS burs, light cuts, high speed, and capture all swarf for refining.
Can Dental Gold Type I be welded?
Laser or micro-plasma spot welding works well in dental labs; conventional fusion welding is rare — gold-based solders are the norm.
Can Dental Gold Type I be formed, bent or molded?
Cast by lost-wax investment casting at roughly 1000–1050 °C into a gypsum-bonded investment; wrought forms cold-work readily with intermediate anneals near 700 °C.
What surface finishes work on Dental Gold Type I?
Polishes to a mirror finish with rouge and does not need plating or coating; margins are closed by burnishing rather than by machining.
Dental Gold Type I 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 |
|---|---|---|
| AuADA Spec No.5 Type I: gold + PGM ≥ 83 % | 83 – 90 | 86 |
| Ag | 3 – 12 | 8.5 |
| Culow Cu — little order-hardening response | 2 – 6 | 4 |
| Pd | 0 – 1.5 | 0.5 |
| Pt | 0 – 1 | 0.3 |
| Zndeoxidiser, improves casting fluidity | 0 – 1.5 | 0.5 |
| Irgrain refiner | 0 – 0.01 | 0.01 |
Dental Gold Type I-AC — frequently asked
What is Dental Gold Type I-AC used for?
Dental Gold Type I-AC is typically used for dental inlays, low-stress single restorations, non-load-bearing occlusal inlays, burnishable cast margins and cast restorations for small cavity preparations. In short: softest dental casting gold; best burnishable margins; low-stress restorations only.
What is the yield strength of Dental Gold Type I-AC?
Dental Gold Type I-AC has a typical yield strength of 90 MPa (13.1 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 86% of precious metal grades. Strength varies by condition: see the 3 listed tempers.
Is Dental Gold Type I-AC easy to machine?
Not especially — machinability is rated fair (40/100, worse than 60% of precious metal grades). Very gummy and smearing — use sharp, high-rake carbide or HSS burs, light cuts, high speed, and capture all swarf for refining.
Can Dental Gold Type I-AC be welded?
Yes — weldability is rated good (60/100). Laser or micro-plasma spot welding works well in dental labs; conventional fusion welding is rare — gold-based solders are the norm.
What surface finishes work on Dental Gold Type I-AC?
Polishes to a mirror finish with rouge and does not need plating or coating; margins are closed by burnishing rather than by machining.
Can Dental Gold Type I-AC be formed, bent or molded?
Cast by lost-wax investment casting at roughly 1000–1050 °C into a gypsum-bonded investment; wrought forms cold-work readily with intermediate anneals near 700 °C.
What is the maximum service temperature of Dental Gold Type I-AC?
Dental Gold Type I-AC 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 Dental Gold Type I-AC and Dental Gold Type I-CW?
AC is the default condition — standard condition of a lost-wax cast inlay; adequate strength with full burnishability. CW: condition of the burnished margin or of drawn wire/foil forms; strength raised at the cost of ductility. Yield strength is 90 MPa in AC versus 180 MPa in CW.
Sources
- ISO 1562 Dentistry — Casting gold alloys — ISO (2004)
- ANSI/ADA Specification No. 5 — Dental Casting Alloys — American Dental Association (2018)
- Craig's Restorative Dental Materials — Elsevier (2019)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys (Precious Metals) — ASM International (1990)
- Dental casting gold alloy datasheets (refiners/alloy makers) — various (2023)
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.