Titanium Grade 4
ASTM Grade 4 · UNS R50700 · EN 3.7065 · GB TA4
Grade 4 is the highest-strength unalloyed commercially pure titanium (UNS R50700, 3.7065, TA4), reaching 550 MPa yield, 620 MPa tensile and 20% elongation at about 253 HB (100 HRB) through controlled oxygen rather than alloying.
Values for the O condition
Grade 4 tempers and conditions
Grade 4 is supplied in 5 conditions, soft to hard. O 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 |
|---|---|---|---|---|---|---|
As-welded deposit | Properties of Grade 4 used as GTAW/GMAW filler metal deposit for joining CP-Ti Grade 3/4 components. | 520 | 620 | 15 | 258 HB | 2.9 % IACS |
Hot rolled | Economical condition for thick plate, billet and forgings that will be machined and, if needed, annealed later. | 540 | 630 | 18 | 255 HB | 2.9 % IACS |
ODefault Annealed | Default stocked condition for sheet, plate, bar and tube — best balance of strength, ductility and weldability. | 550 | 620 | 20 | 253 HB | — |
Stress relieved | Pick for straightness/dimensional stability after cold work or welding while keeping most of the cold-worked yield strength. | 590 | 660 | 18 | 26 HRC | 2.9 % IACS |
Cold worked | Use where maximum strength from unalloyed titanium is needed — dental implants, bone screws, high-pressure small-bore tube. | 700 | 780 | 13 | 31 HRC | — |
What is Grade 4?
Grade 4 is the highest-strength unalloyed commercially pure titanium (UNS R50700, 3.7065, TA4), reaching 550 MPa yield, 620 MPa tensile and 20% elongation at about 253 HB (100 HRB) through controlled oxygen rather than alloying. It is chosen for airframe fittings, tubing and surgical instruments that need strength with CP-grade corrosion resistance and weldability (score 80), and is supplied as sheet, plate, bar and tube. Machinability is the lowest of the CP grades at a score of 30, formability is 50, and it cannot be strengthened by heat treatment, with useful strength limited to about 300 °C. Ti-6Al-4V (Grade 5) is the next step up in strength; Grade 2 or 3 form more easily. Grade 4 has a density of 4.51 g/cm³ (0.163 lb/in³), heavier than 57% of titanium grades. It melts at 1,660°C (3,020 °F). Grade 4 has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 55% of titanium grades. Elongation at break is 20% and the elastic modulus is 105 GPa (15.2 Msi).
What is Grade 4 used for?
- Aircraft tubing and airframe fittings
- Surgical instruments and hand tools
- Orthopaedic and dental components
- High-strength fasteners
- Cryogenic and pressure-vessel parts
- Chemical plant hardware
- Marine shafting hardware
Advantages
- Conducts heat well — 17.2 W/m·K (9.94 BTU/hr·ft·°F), better than 88% of titanium grades
Grade 4 properties
Typical room-temperature values for Grade 4-O; bars are the position among titanium grades.
Physical3
Grade 4 has a density of 4.51 g/cm³ (0.163 lb/in³), heavier than 57% of titanium grades. It melts at 1,660°C (3,020 °F).
Mechanical16
Grade 4 has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 55% of titanium grades. Elongation at break is 20% and the elastic modulus is 105 GPa (15.2 Msi).
Thermal6
Grade 4 is rated for continuous service to 300°C (572 °F). It conducts heat at 17.2 W/m·K (9.94 BTU/hr·ft·°F), better than 88% of titanium grades. Thermal expansion is 9 µm/m·K (5 µin/in·°F).
Electrical3
Grade 4 conducts electricity at 2.9 % IACS, better than 58% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 53% of titanium grades.
Sustainability4
Producing a kilogram of Grade 4 takes about 700 MJ of energy and emits 45 kg of CO₂ — more than 74% of titanium grades. Typical recycled content is 25%.
Manufacturability8
Grade 4's machinability is poor (30/100, better than 64% of titanium grades); weldability very good (80/100); formability fair (50/100).
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. Grade 4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Grade 4
Is Grade 4 easy to machine?
Machine with rigid setups, sharp uncoated-carbide or coated inserts, low surface speed (25–45 m/min), heavy feed and flood coolant; never dwell — the low thermal conductivity and chip galling cause work hardening and fire risk from fine chips.
Can Grade 4 be welded?
Readily GTAW/GMAW/EB/laser welded with matching ERTi-4 filler under full argon/helium shielding plus trailing shield and backing gas; keep the weld and HAZ below straw colour, and avoid hydrogen/oxygen/nitrogen pickup which embrittles the joint.
Can Grade 4 be formed, bent or molded?
Cold form with generous bend radii (≈3–4 t) and allow for high springback; warm forming at 200–400 °C markedly improves formability, and hot working/forging is done at 815–955 °C.
Manufacturability
The process limits FabDigit's quote engine applies to Grade 4. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Fair30 / 100 |
|---|---|
| ISO material group | S.4 |
| Cutting speed (rough / finish) | 90 / 110 m/min |
| Minimum wall | 1 mm |
| Minimum internal radius | 1.5 mm |
| Drill depth limit | 4.5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better50 / 100 |
|---|---|
| Weldability | Better80 / 100 |
| Bendable | Yes |
Grade 4 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 |
|---|---|---|
| Nnitrogen, max | ≤ 0.05 | 0.02 |
| Ccarbon, max | ≤ 0.08 | 0.02 |
| Hhydrogen, max (0.0125 for some product forms) | ≤ 0.02 | 0.01 |
| Feiron, max | ≤ 0.5 | 0.3 |
| Ooxygen, max — main strengthener | ≤ 0.4 | 0.34 |
| Residual eachother elements, each | ≤ 0.1 | |
| Residual totalother elements, total | ≤ 0.4 | |
| Tibalance, ≈99.0 % min | balance |
What surface finishes work on Grade 4?
Pickle in HNO₃/HF to remove alpha case and scale after hot work, then bead blast, passivate, colour anodize (Type II) or hard anodize/nitride for wear; avoid iron-contaminated abrasives which spoil corrosion resistance.
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).
Passivation
Conversion Coating
Organic Coating
CVD Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Titanium Grade 4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- R50700
- EN / DIN / Werkstoff-Nr.
- 3.7065
- GB (China)
- TA4
- Trade names
- CP Ti
How much does Grade 4 cost?
Grade 4 is a specialty-cost titanium ($$$$$), pricier than about 99% 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.
Grade 4 — frequently asked
What is Grade 4 used for?
Grade 4 is typically used for aircraft tubing and airframe fittings, surgical instruments and hand tools, orthopaedic and dental components, high-strength fasteners, cryogenic and pressure-vessel parts and chemical plant hardware. In short: high-strength CP titanium.
What is the yield strength of Grade 4?
Grade 4 has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 55% of titanium grades. Strength varies by condition: see the 5 listed tempers.
Is Grade 4 easy to machine?
Not especially — machinability is rated poor (30/100, better than 64% of titanium grades). Machine with rigid setups, sharp uncoated-carbide or coated inserts, low surface speed (25–45 m/min), heavy feed and flood coolant; never dwell — the low thermal conductivity and chip galling cause work hardening and fire risk from fine chips.
Can Grade 4 be welded?
Yes — weldability is rated very good (80/100). Readily GTAW/GMAW/EB/laser welded with matching ERTi-4 filler under full argon/helium shielding plus trailing shield and backing gas; keep the weld and HAZ below straw colour, and avoid hydrogen/oxygen/nitrogen pickup which embrittles the joint.
What surface finishes work on Grade 4?
Pickle in HNO₃/HF to remove alpha case and scale after hot work, then bead blast, passivate, colour anodize (Type II) or hard anodize/nitride for wear; avoid iron-contaminated abrasives which spoil corrosion resistance.
Can Grade 4 be formed, bent or molded?
Cold form with generous bend radii (≈3–4 t) and allow for high springback; warm forming at 200–400 °C markedly improves formability, and hot working/forging is done at 815–955 °C.
What is the maximum service temperature of Grade 4?
Grade 4 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 Grade 4-O and Grade 4-CW?
O is the default condition — default stocked condition for sheet, plate, bar and tube — best balance of strength, ductility and weldability. CW: use where maximum strength from unalloyed titanium is needed — dental implants, bone screws, high-pressure small-bore tube. Yield strength is 550 MPa in O versus 700 MPa in CW.
How much does Grade 4 cost?
Grade 4 is a specialty-cost titanium ($$$$$), pricier than about 99% 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.
Can FabDigit make parts in Grade 4?
Yes — Grade 4 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
- ASTM B265 — Titanium and Titanium Alloy Strip, Sheet, and Plate — ASTM International (2020)
- ASTM B348 — Titanium and Titanium Alloy Bars and Billets — ASTM International (2021)
- ASTM F67 — Unalloyed Titanium for Surgical Implant Applications — ASTM International (2017)
- AWS A5.16 — Titanium and Titanium-Alloy Welding Electrodes and Rods — AWS (2013)
- GB/T 3621 — (TA4) — SAC (2022)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.13B / Vol.16 — Corrosion and Machining — ASM International (2005)
- CP Titanium Grade 4 mill product data — TIMET / Baoji Titanium (2023)
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.