Titanium Ti-5553 · heat-treated state
Titanium Ti-5553 STOA
Properties of the STOA condition, compared with the other Ti-5553 tempers.
Use when fracture toughness and thermal/dimensional stability are prioritised over peak strength.
What is Ti-5553 STOA?
Ti-5553 STOA is Ti-5553 heat treated to STOA — use when fracture toughness and thermal/dimensional stability are prioritised over peak strength. Ti-5553 STOA has a yield strength of 1,040 MPa (151 ksi) and a tensile strength of 1,120 MPa (162 ksi) — stronger than 95% of titanium grades. Elongation at break is 12% and the elastic modulus is 105 GPa (15.2 Msi). Ti-5553 STOA has a density of 4.65 g/cm³ (0.168 lb/in³), heavier than 90% of titanium grades. It melts at 1,580°C (2,876 °F). O is the default condition FabDigit quotes; STOA is available on request or by drawing note.
Advantages
- High strength — 1,040 MPa (151 ksi), better than 95% of titanium grades
Limitations
- Difficult to machine — 14/100, worse than 100% of titanium grades
- Hard to polish — 60/100, worse than 97% of titanium grades
- Difficult to weld — 35/100, worse than 96% of titanium grades
- Limited ductility — 12%, worse than 78% of titanium grades
Ti-5553 STOA properties
Typical room-temperature values for Ti-5553 STOA — 10 properties are specific to this condition; the rest are grade-level values shared by every Ti-5553 temper. Each bar shows where the value sits among the titanium grades in FabDigit's library — further right is higher.
Physical3
Ti-5553 STOA has a density of 4.65 g/cm³ (0.168 lb/in³), heavier than 90% of titanium grades. It melts at 1,580°C (2,876 °F).
Mechanical16
Ti-5553 STOA has a yield strength of 1,040 MPa (151 ksi) and a tensile strength of 1,120 MPa (162 ksi) — stronger than 95% of titanium grades. Elongation at break is 12% and the elastic modulus is 105 GPa (15.2 Msi).
Thermal6
Ti-5553 STOA is rated for continuous service to 300°C (572 °F). It conducts heat at 7 W/m·K (4.04 BTU/hr·ft·°F), worse than 76% of titanium grades. Thermal expansion is 9.3 µm/m·K (5.17 µin/in·°F).
Electrical3
Ti-5553 STOA conducts electricity at 1.1 % IACS, worse than 67% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), worse than 77% of titanium grades.
Sustainability4
Producing a kilogram of Ti-5553 STOA takes about 650 MJ of energy and emits 42 kg of CO₂ — less than 75% of titanium grades. Typical recycled content is 25%.
Manufacturability8
Ti-5553 STOA's machinability is not recommended (14/100, worse than 100% of titanium grades); weldability fair (35/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other Ti-5553 tempers and conditions
Ti-5553 is also supplied in 6 other conditions. The full side-by-side table is on the Ti-5553 overview.
- ODefaultStandard as-supplied mill condition for bar, billet and forging stock; balanced strength and ductility before final aging.900 MPa yield · 33 HRC
- STA-HSChoose when peak strength matters more than toughness (small, low-K-critical parts, fasteners, actuator components).1,240 MPa yield · 43 HRC
- STAThe standard high-strength delivery condition for landing-gear and structural forgings; use when 170 ksi class strength through thick sections is required.1,150 MPa yield · 40 HRC
- STOAUse when fracture toughness and thermal/dimensional stability are prioritised over peak strength.1,040 MPa yield · 37 HRC
- BASCAPick for very thick landing-gear forgings where fracture toughness and section-size uniformity dominate over ultimate strength.1,020 MPa yield · 36 HRC
- STPick for maximum ductility and easiest machining/forming before the customer performs the final aging cycle.830 MPa yield · 30 HRC
Working with Ti-5553 STOA
Is Ti-5553 easy to machine?
Very difficult: rigid setups, sharp uncoated-carbide or PVD-coated tools, low surface speed (15–30 m/min aged), heavy feed, high-pressure flood coolant, no dwelling — rough machine in ST condition and finish after aging with light depth to avoid white layer.
Can Ti-5553 be welded?
GTAW/plasma/EB weldable with full inert-gas or vacuum shielding and matching filler, but the HAZ loses aged strength; post-weld solution treat plus age is normally required, so welding is avoided on primary structure.
Can Ti-5553 be formed, bent or molded?
Forge and hot-form just below the β transus (~805–855 °C) with tight temperature control to set α morphology; cold forming is impractical except mild bending in the solution-treated condition.
What surface finishes work on Ti-5553?
Grit-blast/pickle (HNO₃–HF) to remove alpha case after hot work, shot peen for fatigue life; titanium anodise (AMS 2488) or ion-plating/dry-film lube for fretting and galling; never plate cadmium and avoid chlorinated cleaners before heat treatment.
Ti-5553 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 | 4.4 – 5.7 | 5 |
| V | 4 – 5.5 | 5 |
| Mo | 4 – 5.5 | 5 |
| Cr | 2.5 – 3.5 | 3 |
| Feintentional β-stabiliser addition | 0.3 – 0.5 | 0.4 |
| Ointerstitial, controls strength | 0.1 – 0.18 | 0.15 |
| C | ≤ 0.04 | — |
| N | ≤ 0.05 | — |
| Hmax (0.0125 typical for forgings) | ≤ 0.02 | — |
| Y | ≤ 0.01 | — |
| Other, eachresiduals, total 0.40 max | ≤ 0.1 | — |
| Ti | balance | — |
Ti-5553 STOA — frequently asked
What is Ti-5553 STOA used for?
Ti-5553 STOA is typically used for aerospace landing gear forgings, high-strength airframe fasteners, wing-to-body and pylon fittings, actuator components and pistons, slat and flap track structures and machined structural clevises and lugs. In short: premium β-titanium forging.
What is the yield strength of Ti-5553 STOA?
Ti-5553 STOA has a typical yield strength of 1,040 MPa (151 ksi) and a tensile strength of 1,120 MPa (162 ksi) — stronger than 95% of titanium grades. Strength varies by condition: see the 7 listed tempers.
Is Ti-5553 STOA easy to machine?
Not especially — machinability is rated not recommended (14/100, worse than 100% of titanium grades). Very difficult: rigid setups, sharp uncoated-carbide or PVD-coated tools, low surface speed (15–30 m/min aged), heavy feed, high-pressure flood coolant, no dwelling — rough machine in ST condition and finish after aging with light depth to avoid white layer.
Can Ti-5553 STOA be welded?
With care — weldability is rated fair (35/100). GTAW/plasma/EB weldable with full inert-gas or vacuum shielding and matching filler, but the HAZ loses aged strength; post-weld solution treat plus age is normally required, so welding is avoided on primary structure.
What surface finishes work on Ti-5553 STOA?
Grit-blast/pickle (HNO₃–HF) to remove alpha case after hot work, shot peen for fatigue life; titanium anodise (AMS 2488) or ion-plating/dry-film lube for fretting and galling; never plate cadmium and avoid chlorinated cleaners before heat treatment.
Can Ti-5553 STOA be formed, bent or molded?
Forge and hot-form just below the β transus (~805–855 °C) with tight temperature control to set α morphology; cold forming is impractical except mild bending in the solution-treated condition.
What is the maximum service temperature of Ti-5553 STOA?
Ti-5553 STOA 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 Ti-5553-O and Ti-5553 STA-HS?
O is the default condition — standard as-supplied mill condition for bar, billet and forging stock; balanced strength and ductility before final aging. STA-HS: choose when peak strength matters more than toughness (small, low-K-critical parts, fasteners, actuator components). Yield strength is 900 MPa in O versus 1,240 MPa in STA-HS.
Can FabDigit make parts in Ti-5553 STOA?
Yes — Ti-5553 STOA 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
- AMS 6932 — Titanium Alloy Forgings, 5Al-5V-5Mo-3Cr — SAE International (2018)
- AMS 4983 — Ti-5Al-5V-5Mo-3Cr Bar and Billet — SAE International (2017)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Titanium: A Technical Guide, 2nd ed. (metastable β alloys) — ASM International (2000)
- Ti-5Al-5V-5Mo-3Cr (Ti-5553) alloy data — TIMET / VSMPO-AVISMA (2020)
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.