Titanium Ti-4Al-4Mo-2Sn-ANN (Annealed)
Heat-treated state
EN 3.7185 · also IMI 550
Pick for stock bar/forgings that will be machined and heat treated later, or where maximum ductility and stability matter more than peak strength.
Values for the ANN condition
Other Ti-4Al-4Mo-2Sn tempers and conditions
Ti-4Al-4Mo-2Sn is listed in 4 conditions; see the grade overview at Ti-4Al-4Mo-2Sn.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNThis page Annealed | Pick for stock bar/forgings that will be machined and heat treated later, or where maximum ductility and stability matter more than peak strength. | 900 | 1,010 | 16 | 32 HRC | — |
β-processed / β-annealed + aged | Choose when damage tolerance, creep and crack-growth resistance outrank ductility — transformed-β structure trades tensile elongation for toughness. | 970 | 1,080 | 8 | 35 HRC | — |
Stress relieved | Applied to welded or heavily machined parts to remove residual stress with only a small strength change from the prior condition. | 990 | 1,100 | 14 | 35 HRC | 1.1 % IACS |
STADefault Solution treated and aged | Standard supply condition for aero-engine discs, shafts and high-strength forgings up to ~425 °C; use for peak strength in sections under ~50–75 mm. | 1,030 | 1,150 | 13 | 36 HRC | — |
What is Ti-4Al-4Mo-2Sn-ANN?
Ti-4Al-4Mo-2Sn-ANN is Ti-4Al-4Mo-2Sn heat treated to ANN — pick for stock bar/forgings that will be machined and heat treated later, or where maximum ductility and stability matter more than peak strength. Ti-4Al-4Mo-2Sn-ANN has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,010 MPa (146 ksi) — stronger than 82% of titanium grades. Elongation at break is 16% and the elastic modulus is 112 GPa (16.2 Msi). Ti-4Al-4Mo-2Sn-ANN has a density of 4.6 g/cm³ (0.166 lb/in³), heavier than 87% of titanium grades. It melts at 1,620°C (2,948 °F). STA is the default condition FabDigit quotes; ANN is available on request or by drawing note.
Advantages
- High strength — 900 MPa (131 ksi), better than 82% of titanium grades
- High service temperature — 400°C (752 °F), better than 78% of titanium grades
Limitations
- Difficult to weld — 35/100, worse than 96% of titanium grades
- Limited formability — 18/100, worse than 89% of titanium grades
Ti-4Al-4Mo-2Sn-ANN properties
Typical room-temperature values for Ti-4Al-4Mo-2Sn-ANN; 18 are specific to this condition. Other listed values are Ti-4Al-4Mo-2Sn reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
Ti-4Al-4Mo-2Sn-ANN has a density of 4.6 g/cm³ (0.166 lb/in³), heavier than 87% of titanium grades. It melts at 1,620°C (2,948 °F).
Mechanical16
Ti-4Al-4Mo-2Sn-ANN has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,010 MPa (146 ksi) — stronger than 82% of titanium grades. Elongation at break is 16% and the elastic modulus is 112 GPa (16.2 Msi).
Thermal6
Ti-4Al-4Mo-2Sn-ANN is rated for continuous service to 400°C (752 °F). It conducts heat at 7.1 W/m·K (4.1 BTU/hr·ft·°F), worse than 68% of titanium grades. Thermal expansion is 9.4 µm/m·K (5.22 µin/in·°F).
Electrical3
Ti-4Al-4Mo-2Sn-ANN conducts electricity at 1.1 % IACS, worse than 67% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), worse than 93% of titanium grades.
Sustainability4
Producing a kilogram of Ti-4Al-4Mo-2Sn-ANN takes about 700 MJ of energy and emits 45 kg of CO₂ — more than 74% of titanium grades. Typical recycled content is 25%.
Manufacturability8
Ti-4Al-4Mo-2Sn-ANN's machinability is poor (19/100, worse than 78% of titanium grades); weldability fair (35/100); formability poor (18/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Ti-4Al-4Mo-2Sn-ANN
Is Ti-4Al-4Mo-2Sn easy to machine?
Machine like a hard α+β titanium: rigid setup, sharp uncoated-carbide or PVD-coated tools, ~25–45 m/min in the STA condition, high-pressure flood coolant, positive feed to avoid work-hardening and never dwell.
Can Ti-4Al-4Mo-2Sn be welded?
GTAW/EBW/plasma in full inert shielding is possible but the aged microstructure is destroyed — post-weld solution + age (or at minimum stress relief) is required and weld ductility remains low, so welding is avoided on rotating parts.
Can Ti-4Al-4Mo-2Sn be formed, bent or molded?
Essentially a hot-work alloy: forge/roll just below the ~975 °C β transus and hot form at 700–850 °C; cold forming is limited to very gentle bends on annealed thin stock.
What surface finishes work on Ti-4Al-4Mo-2Sn?
Grit blast plus chemical (HF/HNO3) pickle to remove alpha case, then Type II anodize, ion nitriding or dry-film lube for galling/fretting control; polishes well but never leave scale from hot working.
Ti-4Al-4Mo-2Sn 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 |
|---|---|---|
| Alα stabiliser | 3 – 5 | 4 |
| Moβ stabiliser, solid-solution strengthening | 3.5 – 4.5 | 4 |
| Sn | 1.5 – 2.5 | 2 |
| Sicreep resistance via silicide precipitation | 0.3 – 0.7 | 0.5 |
| Fe | ≤ 0.2 | — |
| O | ≤ 0.2 | 0.13 |
| C | ≤ 0.08 | — |
| N | ≤ 0.05 | — |
| H | ≤ 0.01 | — |
| Ti | balance | — |
Ti-4Al-4Mo-2Sn-ANN — frequently asked
What is Ti-4Al-4Mo-2Sn-ANN used for?
Ti-4Al-4Mo-2Sn-ANN is typically used for jet engine compressor discs, high-temperature fasteners, compressor blades and blisks, engine shafts and spacers, forged aero-engine rotating hardware and highly loaded airframe fittings. In short: high-strength engine disc alloy; service to 425 °C; forged, not formed.
What is the yield strength of Ti-4Al-4Mo-2Sn-ANN?
Ti-4Al-4Mo-2Sn-ANN has a typical yield strength of 900 MPa (131 ksi) and a tensile strength of 1,010 MPa (146 ksi) — stronger than 82% of titanium grades. Strength varies by condition: see the 4 listed tempers.
Is Ti-4Al-4Mo-2Sn-ANN easy to machine?
Not especially — machinability is rated poor (19/100, worse than 78% of titanium grades). Machine like a hard α+β titanium: rigid setup, sharp uncoated-carbide or PVD-coated tools, ~25–45 m/min in the STA condition, high-pressure flood coolant, positive feed to avoid work-hardening and never dwell.
Can Ti-4Al-4Mo-2Sn-ANN be welded?
With care — weldability is rated fair (35/100). GTAW/EBW/plasma in full inert shielding is possible but the aged microstructure is destroyed — post-weld solution + age (or at minimum stress relief) is required and weld ductility remains low, so welding is avoided on rotating parts.
What surface finishes work on Ti-4Al-4Mo-2Sn-ANN?
Grit blast plus chemical (HF/HNO3) pickle to remove alpha case, then Type II anodize, ion nitriding or dry-film lube for galling/fretting control; polishes well but never leave scale from hot working.
Can Ti-4Al-4Mo-2Sn-ANN be formed, bent or molded?
Essentially a hot-work alloy: forge/roll just below the ~975 °C β transus and hot form at 700–850 °C; cold forming is limited to very gentle bends on annealed thin stock.
What is the maximum service temperature of Ti-4Al-4Mo-2Sn-ANN?
Ti-4Al-4Mo-2Sn-ANN is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Ti-4Al-4Mo-2Sn-STA and Ti-4Al-4Mo-2Sn-ANN?
STA is the default condition — standard supply condition for aero-engine discs, shafts and high-strength forgings up to ~425 °C; use for peak strength in sections under ~50–75 mm. ANN: pick for stock bar/forgings that will be machined and heat treated later, or where maximum ductility and stability matter more than peak strength. Yield strength is 1,030 MPa in STA versus 900 MPa in ANN.
Sources
- IMI 550 (Ti-4Al-4Mo-2Sn-0.5Si) alloy data sheet — IMI Titanium / Timet (2000)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- Materials Properties Handbook: Titanium Alloys — ASM International (1994)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- DIN 17851 / Werkstoff-Nr. 3.7185 titanium alloy designation — DIN (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.