Refractory Metal I-70-H
I-70-H is an instrument-grade beryllium with higher BeO content than the structural grades, consolidated by HIP or vacuum hot pressing for long-term dimensional stability.
Reference datasheet — I-70-H 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 HIP condition
I-70-H tempers and conditions
I-70-H is supplied in 3 conditions, soft to hard. HIP 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 |
|---|---|---|---|---|---|---|
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 |
Supply forms, finishes and certifications
Ways I-70-H is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
ETCH | Machined + chem-etched | Surface finish |
What is I-70-H?
I-70-H is an instrument-grade beryllium with higher BeO content than the structural grades, consolidated by HIP or vacuum hot pressing for long-term dimensional stability. It was used for gyroscope and inertial guidance hardware and is supplied as HIP or VHP block, thermally stabilised or etched, with 205 MPa yield, 310 MPa tensile, 4.5% elongation, 70 HRB, 303 GPa modulus and 210 W/m·K. There is no room-temperature formability, arc welding is not practical, and machining requires wet or HEPA-captured dust control; availability is limited to specialty suppliers. I-220H offers higher strength. I-70-H 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). I-70-H has a yield strength of 205 MPa (29.7 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 84% of refractory metal grades. Elongation at break is 4.5% and the elastic modulus is 303 GPa (43.9 Msi).
What is I-70-H used for?
- gyroscope gimbals
- inertial navigation components
- precision instrument parts
Advantages
- Lightweight — 1.85 g/cm³ (0.0668 lb/in³), better than 96% of refractory metal grades
- High electrical conductivity — 41 % IACS, better than 96% of refractory metal grades
- Conducts heat well — 210 W/m·K (121.3 BTU/hr·ft·°F), better than 94% of refractory metal grades
Limitations
- Hard to polish — 50/100, worse than 93% of refractory metal grades
- Limited formability — 8/100, worse than 90% of refractory metal grades
- Low fracture toughness — 12 MPa·√m (10.9 ksi·√in), worse than 87% of refractory metal grades
- Needs corrosion protection — 45/100, worse than 86% of refractory metal grades
- Low strength — 205 MPa (29.7 ksi), worse than 84% of refractory metal grades
I-70-H properties
Typical room-temperature values for I-70-H-HIP; bars are the position among refractory metal grades.
Physical3
I-70-H 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 has a yield strength of 205 MPa (29.7 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 84% of refractory metal grades. Elongation at break is 4.5% and the elastic modulus is 303 GPa (43.9 Msi).
Thermal6
I-70-H is rated for continuous service to 500°C (932 °F). It conducts heat at 210 W/m·K (121.3 BTU/hr·ft·°F), better than 94% of refractory metal grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
I-70-H conducts electricity at 41 % IACS, better than 96% 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 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's machinability is fair (35/100, better than 81% of refractory metal grades); weldability poor (20/100); formability not recommended (8/100).
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 refractory metal family
Yield strength against density for every refractory metal grade FabDigit runs. I-70-H is highlighted; hover a dot for its name, or open the interactive family chart.
Working with I-70-H
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.
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) |
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.
How much does I-70-H cost?
I-70-H is a high-cost refractory metal ($$$$), 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.
I-70-H — frequently asked
What is I-70-H used for?
I-70-H 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?
I-70-H has a typical yield strength of 205 MPa (29.7 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 84% of refractory metal grades. Strength varies by condition: see the 3 listed tempers.
Is I-70-H easy to machine?
Not especially — machinability is rated fair (35/100, better than 81% 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 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?
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 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?
I-70-H 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.
How much does I-70-H cost?
I-70-H is a high-cost refractory metal ($$$$), 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
- 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; 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.