Refractory Metal I-70-H-VHP (Vacuum hot pressed block)
Print state
Older/large-block consolidation route; slightly lower and more anisotropic properties than HIP but adequate for many instrument parts.
Values for the VHP condition
Other I-70-H tempers and conditions
I-70-H is listed in 3 conditions; see the grade overview at I-70-H.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
VHPThis page Vacuum hot pressed block | Older/large-block consolidation route; slightly lower and more anisotropic properties than HIP but adequate for many instrument parts. | 190 | 290 | 3.5 | 115 HB | 40 % IACS |
Thermally stabilized / stress relieved | Pick when long-term dimensional stability (microyield, creep of residual stress) dominates, e.g. gyro rotors and inertial platforms. | 195 | 295 | 5 | 115 HB | 41 % IACS |
HIPDefault Hot isostatic pressed | Standard supply form: near-isotropic HIP consolidated powder block for gyro and inertial-instrument machining. | 205 | 310 | 4.5 | 120 HB | 41 % IACS |
What is I-70-H-VHP?
I-70-H-VHP is I-70-H in the VHP condition — older/large-block consolidation route; slightly lower and more anisotropic properties than HIP but adequate for many instrument parts. I-70-H-VHP has a yield strength of 190 MPa (27.6 ksi) and a tensile strength of 290 MPa (42.1 ksi) — weaker than 91% of refractory metal grades. Elongation at break is 3.5% and the elastic modulus is 300 GPa (43.5 Msi). I-70-H-VHP has a density of 1.85 g/cm³ (0.0668 lb/in³), lighter than 96% of refractory metal grades. It melts at 1,287°C (2,349 °F). HIP is the default condition FabDigit quotes; VHP is available on request or by drawing note.
Advantages
- Lightweight — 1.85 g/cm³ (0.0668 lb/in³), better than 96% of refractory metal grades
- High electrical conductivity — 40 % IACS, better than 93% of refractory metal grades
- Conducts heat well — 205 W/m·K (118.4 BTU/hr·ft·°F), better than 91% of refractory metal grades
Limitations
- Hard to polish — 50/100, worse than 93% of refractory metal grades
- Low fracture toughness — 11 MPa·√m (10 ksi·√in), worse than 92% of refractory metal grades
- Low strength — 190 MPa (27.6 ksi), worse than 91% of refractory metal grades
- Limited formability — 6/100, worse than 91% of refractory metal grades
- Needs corrosion protection — 45/100, worse than 86% of refractory metal grades
I-70-H-VHP properties
Typical room-temperature values for I-70-H-VHP; 22 are specific to this condition. Other listed values are I-70-H reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
I-70-H-VHP has a density of 1.85 g/cm³ (0.0668 lb/in³), lighter than 96% of refractory metal grades. It melts at 1,287°C (2,349 °F).
Mechanical16
I-70-H-VHP has a yield strength of 190 MPa (27.6 ksi) and a tensile strength of 290 MPa (42.1 ksi) — weaker than 91% of refractory metal grades. Elongation at break is 3.5% and the elastic modulus is 300 GPa (43.5 Msi).
Thermal6
I-70-H-VHP is rated for continuous service to 500°C (932 °F). It conducts heat at 205 W/m·K (118.4 BTU/hr·ft·°F), better than 91% of refractory metal grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
I-70-H-VHP conducts electricity at 40 % IACS, better than 93% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 86% of refractory metal grades.
Sustainability4
Producing a kilogram of I-70-H-VHP takes about 1,600 MJ of energy and emits 105 kg of CO₂ — more than 80% of refractory metal grades. Typical recycled content is 10%.
Manufacturability8
I-70-H-VHP's machinability is poor (34/100, better than 73% of refractory metal grades); weldability poor (20/100); formability not recommended (6/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with I-70-H-VHP
Is I-70-H easy to machine?
Machines like a hard, abrasive grey iron with carbide/diamond tooling, but all cutting must be wet or fully ventilated with HEPA capture — beryllium dust is a chronic-disease hazard; finish with an acid etch to remove the twinned damaged layer.
Can I-70-H be welded?
Fusion welding is avoided (hot cracking, coarse grain); electron-beam welding with Al-Be filler, Al-Si/Ag-Cu brazing, or mechanical fastening are the practical joining routes.
Can I-70-H be formed, bent or molded?
Essentially no room-temperature formability — parts are machined from HIP block; any forming or bending must be done warm (400–800 °C) with careful strain control.
What surface finishes work on I-70-H?
Chromate conversion or anodic passivation for corrosion protection; electroless nickel plate where a polished optical, bearing or solderable surface is needed; avoid halide-containing cleaners.
I-70-H 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 |
|---|---|---|
| BeOberyllium oxide content — key instrument-grade control | ≤ 0.7 | 0.6 |
| C | ≤ 0.07 | 0.05 |
| Fe | ≤ 0.1 | 0.07 |
| Al | ≤ 0.06 | 0.04 |
| Mg | ≤ 0.06 | 0.02 |
| Si | ≤ 0.06 | 0.03 |
| Other metallic, each | ≤ 0.04 | — |
| Beberyllium assay, wt% of metal | ≥ 99 (balance) | — |
I-70-H-VHP — frequently asked
What is I-70-H-VHP used for?
I-70-H-VHP is typically used for gyroscope gimbals, inertial navigation components and precision instrument parts. In short: dimensionally stable instrument Be; legacy gyroscope grade; high modulus, low density.
What is the yield strength of I-70-H-VHP?
I-70-H-VHP has a typical yield strength of 190 MPa (27.6 ksi) and a tensile strength of 290 MPa (42.1 ksi) — weaker than 91% of refractory metal grades. Strength varies by condition: see the 3 listed tempers.
Is I-70-H-VHP easy to machine?
Not especially — machinability is rated poor (34/100, better than 73% of refractory metal grades). Machines like a hard, abrasive grey iron with carbide/diamond tooling, but all cutting must be wet or fully ventilated with HEPA capture — beryllium dust is a chronic-disease hazard; finish with an acid etch to remove the twinned damaged layer.
Can I-70-H-VHP be welded?
Not readily — weldability is rated poor (20/100). Fusion welding is avoided (hot cracking, coarse grain); electron-beam welding with Al-Be filler, Al-Si/Ag-Cu brazing, or mechanical fastening are the practical joining routes.
What surface finishes work on I-70-H-VHP?
Chromate conversion or anodic passivation for corrosion protection; electroless nickel plate where a polished optical, bearing or solderable surface is needed; avoid halide-containing cleaners.
Can I-70-H-VHP be formed, bent or molded?
Essentially no room-temperature formability — parts are machined from HIP block; any forming or bending must be done warm (400–800 °C) with careful strain control.
What is the maximum service temperature of I-70-H-VHP?
I-70-H-VHP is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between I-70-H-HIP and I-70-H-VHP?
HIP is the default condition — standard supply form: near-isotropic HIP consolidated powder block for gyro and inertial-instrument machining. VHP: older/large-block consolidation route; slightly lower and more anisotropic properties than HIP but adequate for many instrument parts. Yield strength is 205 MPa in HIP versus 190 MPa in VHP.
Sources
- Beryllium Grades and Properties (S-65C, S-200F, I-70-H, I-220-H, I-400) — Materion Brush Beryllium & Composites (2022)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys (Beryllium) — ASM International (1990)
- Beryllium Chemistry and Processing — ASM International (2009)
- CRC Handbook of Chemistry and Physics — beryllium thermophysical data — CRC Press (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.