Titanium Grade 7
ASTM Grade 7 · UNS R52400 · EN 3.7235 · JIS Class 17 · GB TA9
Grade 7 (Ti-0.15Pd, UNS R52400, 3.7235, TA9, Class 17) is a palladium-stabilized version of Grade 2, where the small Pd addition shifts corrosion behaviour in reducing acids and raises crevice-corrosion resistance markedly (corrosion score 96).
Values for the O condition
Grade 7 tempers and conditions
Grade 7 is supplied in 3 conditions, soft to hard. O is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ODefault Annealed | Standard stocked condition for all corrosion-service product forms; best ductility and formability. | 320 | 400 | 24 | 160 HB | — |
Grade 7H | Order when a specification demands the 483 MPa minimum UTS 'H' grade (nuclear waste-package and heavy corrosion-barrier work) while keeping Grade 7 chemistry. | 400 | 510 | 20 | 195 HB | 3.1 % IACS |
Cold worked | Pick when higher strength or tighter dimensional tolerance is needed from bar, wire or small tube; ductility and formability drop. | 480 | 550 | 15 | 215 HB | — |
What is Grade 7?
Grade 7 (Ti-0.15Pd, UNS R52400, 3.7235, TA9, Class 17) is a palladium-stabilized version of Grade 2, where the small Pd addition shifts corrosion behaviour in reducing acids and raises crevice-corrosion resistance markedly (corrosion score 96). Annealed properties are 320 MPa yield, 400 MPa tensile and 24% elongation at about 160 HB, with service to 315 °C, and it is used as sheet, plate, bar and welded pipe in aggressive chemical processing. Weldability (85) and formability (75) match Grade 2, but the palladium makes it the most expensive CP grade and strength is slightly lower. Use Grade 2 when crevice attack and hot reducing acids are not the issue. Grade 7 has a density of 4.51 g/cm³ (0.163 lb/in³), heavier than 57% of titanium grades. It melts at 1,665°C (3,029 °F). Grade 7 has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 87% of titanium grades. Elongation at break is 24% and the elastic modulus is 103 GPa (14.9 Msi).
What is Grade 7 used for?
- Hot acid pipework and pumps
- Pulp bleaching plant equipment
- Chlorine-dioxide and brine service vessels
- Heat exchanger tubing for reducing acids
- Chemical reactor internals and liners
- Anodes and electrolytic cell hardware
- Geothermal and hydrometallurgical components
Advantages
- Forms and bends easily — 75/100, better than 83% of titanium grades
- Easy to machine — 35/100, better than 78% of titanium grades
- Ductile — tolerates forming and impact — 24%, better than 77% of titanium grades
- High electrical conductivity — 3.1 % IACS, better than 75% of titanium grades
Limitations
- Low strength — 320 MPa (46.4 ksi), worse than 87% of titanium grades
Grade 7 properties
Typical room-temperature values for Grade 7-O; bars are the position among titanium grades.
Physical3
Grade 7 has a density of 4.51 g/cm³ (0.163 lb/in³), heavier than 57% of titanium grades. It melts at 1,665°C (3,029 °F).
Mechanical16
Grade 7 has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 87% of titanium grades. Elongation at break is 24% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
Grade 7 is rated for continuous service to 315°C (599 °F). It conducts heat at 16.4 W/m·K (9.48 BTU/hr·ft·°F), better than 71% of titanium grades. Thermal expansion is 8.6 µm/m·K (4.78 µin/in·°F).
Electrical3
Grade 7 conducts electricity at 3.1 % IACS, better than 75% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (96/100), better than 92% of titanium grades.
Sustainability4
Producing a kilogram of Grade 7 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 7's machinability is fair (35/100, better than 78% of titanium grades); weldability excellent (85/100); formability very good (75/100).
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 7 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Grade 7
Is Grade 7 easy to machine?
Machine like CP Ti Gr.2: rigid setup, sharp uncoated/ TiAlN carbide, low surface speed (25–45 m/min), heavy flood coolant, avoid dwell to prevent galling and work hardening.
Can Grade 7 be welded?
Excellent GTAW/GMAW/PAW/EB/resistance weldability using matching Gr.7 (ERTi-7) filler; requires full argon shielding of pool, trailing and back-purge, clean oxide-free prep, and colour checks — as-welded joints keep Pd-enhanced corrosion resistance.
Can Grade 7 be formed, bent or molded?
Cold form at generous bend radii (≈2–3 t) with allowance for springback; warm forming 200–400 °C eases severe draws; annealed sheet deep-draws similarly to Gr.2.
Manufacturability
The process limits FabDigit's quote engine applies to Grade 7. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Fair35 / 100 |
|---|---|
| ISO material group | S.3 |
| Cutting speed (rough / finish) | 60 / 75 m/min |
| Minimum wall | 1 mm |
| Minimum internal radius | 1.5 mm |
| Drill depth limit | 4× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better75 / 100 |
|---|---|
| Weldability | Better85 / 100 |
| Bendable | Yes |
Grade 7 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 |
|---|---|---|
| Pdcorrosion-enhancing addition | 0.12 – 0.25 | 0.18 |
| Fe | ≤ 0.3 | 0.15 |
| O | ≤ 0.25 | 0.15 |
| C | ≤ 0.08 | 0.02 |
| N | ≤ 0.03 | 0.01 |
| H0.0125 max for some tube/plate forms | ≤ 0.02 | 0.01 |
| Other, eachresidual elements | ≤ 0.1 | |
| Other, totalresidual elements | ≤ 0.4 | |
| Ti | balance |
What surface finishes work on Grade 7?
Pickle in HNO₃/HF then rinse to restore the passive film; can be colour anodized (AMS 2488), glass-bead or electropolished; avoid iron contamination and steel wire brushing.
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 7 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- R52400
- EN / DIN / Werkstoff-Nr.
- 3.7235
- GB (China)
- TA9
- JIS
- Class 17
- Trade names
- CP Ti-PdTi-Pd
How much does Grade 7 cost?
Grade 7 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 7 — frequently asked
What is Grade 7 used for?
Grade 7 is typically used for hot acid pipework and pumps, pulp bleaching plant equipment, chlorine-dioxide and brine service vessels, heat exchanger tubing for reducing acids, chemical reactor internals and liners and anodes and electrolytic cell hardware. In short: palladium corrosion-proof titanium.
What is the yield strength of Grade 7?
Grade 7 has a typical yield strength of 320 MPa (46.4 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 87% of titanium grades. Strength varies by condition: see the 3 listed tempers.
Is Grade 7 easy to machine?
Not especially — machinability is rated fair (35/100, better than 78% of titanium grades). Machine like CP Ti Gr.2: rigid setup, sharp uncoated/ TiAlN carbide, low surface speed (25–45 m/min), heavy flood coolant, avoid dwell to prevent galling and work hardening.
Can Grade 7 be welded?
Yes — weldability is rated excellent (85/100). Excellent GTAW/GMAW/PAW/EB/resistance weldability using matching Gr.7 (ERTi-7) filler; requires full argon shielding of pool, trailing and back-purge, clean oxide-free prep, and colour checks — as-welded joints keep Pd-enhanced corrosion resistance.
What surface finishes work on Grade 7?
Pickle in HNO₃/HF then rinse to restore the passive film; can be colour anodized (AMS 2488), glass-bead or electropolished; avoid iron contamination and steel wire brushing.
Can Grade 7 be formed, bent or molded?
Cold form at generous bend radii (≈2–3 t) with allowance for springback; warm forming 200–400 °C eases severe draws; annealed sheet deep-draws similarly to Gr.2.
What is the maximum service temperature of Grade 7?
Grade 7 is rated for continuous use to about 315°C (599 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Grade 7-O and Grade 7-CW?
O is the default condition — standard stocked condition for all corrosion-service product forms; best ductility and formability. CW: pick when higher strength or tighter dimensional tolerance is needed from bar, wire or small tube; ductility and formability drop. Yield strength is 320 MPa in O versus 480 MPa in CW.
How much does Grade 7 cost?
Grade 7 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 7?
Yes — Grade 7 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 B338 — Seamless and Welded Titanium and Titanium Alloy Tubes for Condensers and Heat Exchangers — ASTM International (2017)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- Titanium Grade 7 / Ti-0.2Pd corrosion and mechanical data — TIMET / ATI (2018)
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.