Titanium OT4
OT4 is a low-alloy alpha titanium sheet and forging alloy that uses manganese as a low-cost beta-stabiliser substitute, stocked annealed, hot-rolled, cold-rolled hard, stress-relieved and as-welded.
Reference datasheet — OT4 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the M condition
OT4 tempers and conditions
OT4 is supplied in 5 conditions, soft to hard. M is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
MDefault Thermomechanically controlled processed | Standard stocked condition for sheet and plate; best balance of strength, ductility and formability. | 640 | 780 | 16 | 22 HRC | 1.1 % IACS |
As-welded deposit | Reference condition for welded sheet assemblies; joint efficiency is high but ductility drops in the fusion zone. | 640 | 760 | 9 | 23 HRC | 1.1 % IACS |
Stress relieved | Applied after forming, welding or heavy machining to remove residual stress with almost no loss of strength. | 670 | 800 | 15 | 23 HRC | 1.1 % IACS |
Hot rolled | Cheapest mill condition for thick plate and forging stock that will be machined and annealed later. | 690 | 820 | 13 | 25 HRC | 1.1 % IACS |
Cold-rolled, work-hardened sheet | Use only where higher strength and flatness matter more than bend ductility; limited cold-work capacity in Ti. | 820 | 900 | 8 | 29 HRC | 1.1 % IACS |
Supply forms, finishes and certifications
Ways OT4 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
M-BAR | M | Supply form |
What is OT4?
OT4 is a low-alloy alpha titanium sheet and forging alloy that uses manganese as a low-cost beta-stabiliser substitute, stocked annealed, hot-rolled, cold-rolled hard, stress-relieved and as-welded. Annealed material provides about 640 MPa yield, 780 MPa tensile, 16% elongation and 240 HB with service to 350 °C, which suits moderately loaded formed and welded sheet parts. Cold formability is moderate (score 55) and machinability is low (score 28); OT4-1 is the softer, more formable option and TA17 a close near-alpha alternative. OT4 has a density of 4.55 g/cm³ (0.164 lb/in³), heavier than 84% of titanium grades. It melts at 1,620°C (2,948 °F). OT4 has a yield strength of 640 MPa (92.8 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 51% of titanium grades. Elongation at break is 16% and the elastic modulus is 115 GPa (16.7 Msi).
What is OT4 used for?
- Sheet metal parts and panels
- Forged fittings
- Welded sheet assemblies
- Formed brackets and stiffeners
- Ducting and tube components
- Moderately loaded structural covers
OT4 properties
Typical room-temperature values for OT4-M; bars are the position among titanium grades.
Physical3
OT4 has a density of 4.55 g/cm³ (0.164 lb/in³), heavier than 84% of titanium grades. It melts at 1,620°C (2,948 °F).
Mechanical17
OT4 has a yield strength of 640 MPa (92.8 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 51% of titanium grades. Elongation at break is 16% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal6
OT4 is rated for continuous service to 350°C (662 °F). It conducts heat at 9.5 W/m·K (5.49 BTU/hr·ft·°F), better than 56% of titanium grades. Thermal expansion is 8.6 µm/m·K (4.78 µin/in·°F).
Electrical3
OT4 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 OT4 takes about 620 MJ of energy and emits 38 kg of CO₂ — less than 97% of titanium grades. Typical recycled content is 25%.
Manufacturability7
OT4's machinability is poor (28/100, better than 59% of titanium grades); weldability very good (72/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the titanium family
Yield strength against density for every titanium grade FabDigit runs. OT4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with OT4
Is OT4 easy to machine?
Machine like other titanium: rigid setup, sharp uncoated-carbide or coated tools, low surface speed (25–45 m/min), heavy positive feed and flood coolant to avoid work-hardening, galling and chip fires.
Can OT4 be welded?
Good fusion weldability by GTAW, plasma or EBW with full argon/vacuum shielding and trailing gas; keep interstitials low, clean thoroughly, and stress-relieve rather than post-weld solution treat.
Can OT4 be formed, bent or molded?
Annealed sheet cold-bends to moderate radii (~3–4 t) but springs back strongly; warm forming at 300–500 °C markedly improves formability and dimensional control.
OT4 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 |
|---|---|---|
| Alalpha stabiliser | 3.5 – 5 | 4.2 |
| Mnlow-cost beta stabiliser | 0.8 – 2 | 1.5 |
| Zrimpurity limit | ≤ 0.3 | |
| Si | ≤ 0.15 | |
| Fe | ≤ 0.3 | |
| C | ≤ 0.1 | |
| O | ≤ 0.15 | |
| N | ≤ 0.05 | |
| Hhydrogen embrittlement control | ≤ 0.01 | |
| other impurities (total) | ≤ 0.3 | |
| Ti | balance |
What surface finishes work on OT4?
Pickle in HNO3/HF (short times, then bake to avoid hydrogen pickup), then anodise or apply plasma-electrolytic oxide for colour/wear; can be bead-blasted, brushed or polished, and takes primer/paint well after conversion coating.
Surface treatments FabDigit runs on titanium parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Thermal Spray
How much does OT4 cost?
OT4 is a high-cost titanium ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
OT4 — frequently asked
What is OT4 used for?
OT4 is typically used for sheet metal parts and panels, forged fittings, welded sheet assemblies, formed brackets and stiffeners, ducting and tube components and moderately loaded structural covers. In short: manganese-stabilised low-cost alpha; formable weldable sheet grade; 350 °C service ceiling.
What is the yield strength of OT4?
OT4 has a typical yield strength of 640 MPa (92.8 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 51% of titanium grades. Strength varies by condition: see the 5 listed tempers.
Is OT4 easy to machine?
Not especially — machinability is rated poor (28/100, better than 59% of titanium grades). Machine like other titanium: rigid setup, sharp uncoated-carbide or coated tools, low surface speed (25–45 m/min), heavy positive feed and flood coolant to avoid work-hardening, galling and chip fires.
Can OT4 be welded?
Yes — weldability is rated very good (72/100). Good fusion weldability by GTAW, plasma or EBW with full argon/vacuum shielding and trailing gas; keep interstitials low, clean thoroughly, and stress-relieve rather than post-weld solution treat.
What surface finishes work on OT4?
Pickle in HNO3/HF (short times, then bake to avoid hydrogen pickup), then anodise or apply plasma-electrolytic oxide for colour/wear; can be bead-blasted, brushed or polished, and takes primer/paint well after conversion coating.
Can OT4 be formed, bent or molded?
Annealed sheet cold-bends to moderate radii (~3–4 t) but springs back strongly; warm forming at 300–500 °C markedly improves formability and dimensional control.
What is the maximum service temperature of OT4?
OT4 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between OT4-M and OT4 CR-H?
M is the default condition — standard stocked condition for sheet and plate; best balance of strength, ductility and formability. CR-H: use only where higher strength and flatness matter more than bend ductility; limited cold-work capacity in Ti. Yield strength is 640 MPa in M versus 820 MPa in CR-H.
How much does OT4 cost?
OT4 is a high-cost titanium ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- GOST 19807 — Titanium and titanium alloys, grades — Gosstandart (1991)
- GOST 22178 — Titanium alloy sheets, technical requirements — Gosstandart (1976)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (titanium section) — ASM International (1990)
- Titanium Alloys of the CIS — physical and mechanical property tables (VIAM data compilations) — VIAM / Metallurgiya (2000)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.