Refractory Metal Pure Mo · heat-treated state
Refractory Metal Pure Mo Stress Relieved
Properties of the Stress Relieved condition, compared with the other Pure Mo tempers.
Pick when flatness/dimensional stability and lower residual stress matter but wrought ductility must be kept (most sheet for forming, sputter targets).
What is Pure Mo Stress Relieved?
Pure Mo Stress Relieved is Pure Mo heat treated to Stress Relieved — pick when flatness/dimensional stability and lower residual stress matter but wrought ductility must be kept (most sheet for forming, sputter targets). Pure Mo Stress Relieved has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 68% of refractory metal grades. Elongation at break is 20% and the elastic modulus is 320 GPa (46.4 Msi). Pure Mo Stress Relieved has a density of 10.22 g/cm³ (0.369 lb/in³), heavier than 67% of refractory metal grades. It melts at 2,623°C (4,753 °F). As Rolled is the default condition FabDigit quotes; Stress Relieved is available on request or by drawing note.
Advantages
- Easy to machine — 42/100, better than 97% of refractory metal grades
- High electrical conductivity — 32 % IACS, better than 88% of refractory metal grades
- Conducts heat well — 138 W/m·K (79.7 BTU/hr·ft·°F), better than 87% of refractory metal grades
- Stiff — 320 GPa (46.4 Msi), better than 82% of refractory metal grades
- Low embodied carbon — 25 kg CO₂/kg, better than 79% of refractory metal grades
Limitations
- Difficult to weld — 20/100, worse than 79% of refractory metal grades
Pure Mo Stress Relieved properties
Typical room-temperature values for Pure Mo Stress Relieved — 11 properties are specific to this condition; the rest are grade-level values shared by every Pure Mo temper. Each bar shows where the value sits among the refractory metal grades in FabDigit's library — further right is higher.
Physical3
Pure Mo Stress Relieved has a density of 10.22 g/cm³ (0.369 lb/in³), heavier than 67% of refractory metal grades. It melts at 2,623°C (4,753 °F).
Mechanical16
Pure Mo Stress Relieved has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 68% of refractory metal grades. Elongation at break is 20% and the elastic modulus is 320 GPa (46.4 Msi).
Thermal6
Pure Mo Stress Relieved is rated for continuous service to 500°C (932 °F). It conducts heat at 138 W/m·K (79.7 BTU/hr·ft·°F), better than 87% of refractory metal grades. Thermal expansion is 5.2 µm/m·K (2.89 µin/in·°F).
Electrical3
Pure Mo Stress Relieved conducts electricity at 32 % IACS, better than 88% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 74% of refractory metal grades.
Sustainability4
Producing a kilogram of Pure Mo Stress Relieved takes about 380 MJ of energy and emits 25 kg of CO₂ — less than 77% of refractory metal grades. Typical recycled content is 30%.
Manufacturability7
Pure Mo Stress Relieved's machinability is fair (42/100, better than 97% of refractory metal grades); weldability poor (20/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other Pure Mo tempers and conditions
Pure Mo is also supplied in 6 other conditions. The full side-by-side table is on the Pure Mo overview.
- As RolledDefaultDefault stock condition for sheet, plate and bar — highest strength and hardness, retains wrought fibrous structure.590 MPa yield · 95 HRB
- Stress RelievedPick when flatness/dimensional stability and lower residual stress matter but wrought ductility must be kept (most sheet for forming, sputter targets).450 MPa yield · 90 HRB
- Arc Cast SRChoose arc-cast Mo when low interstitial oxygen, cleaner grain boundaries and better ductility/weld response than P/M material are needed.400 MPa yield · 210 HV
- SinteredLowest-cost as-sintered form for crucibles, electrodes and blanks where residual porosity and low ductility are acceptable.300 MPa yield · 170 HV
- RecrystallizedUse only where softness/low hardness or deep drawing after re-anneal is required; recrystallized Mo is notch-brittle at room temperature.280 MPa yield · 78 HRB
Working with Pure Mo Stress Relieved
Is Pure Mo easy to machine?
Machinable with sharp carbide or CBN tooling, positive rake, rigid setup and flood coolant; chips are short and brittle, edges chip easily — deburr and stress-relieve after heavy cuts, EDM and grinding work well.
Can Pure Mo be welded?
Poor fusion weldability — electron-beam or laser welding in vacuum/high-purity inert gas only; welds recrystallize and are notch-brittle, so vacuum brazing or mechanical joining is preferred.
Can Pure Mo be formed, bent or molded?
Warm form at roughly 150–400 °C (higher for thick sections) with generous bend radii; cold bending of recrystallized or thick material causes cracking.
What surface finishes work on Pure Mo?
Chemically clean/etch and vacuum-degas before use; not anodizable — apply Ni or Cr plating for aqueous corrosion, and Si/MoSi2 or Pt-based coatings for service above 500 °C in air.
Pure Mo 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 |
|---|---|---|
| C | ≤ 0.01 | 0 |
| Olower (<0.002) in arc-cast Type 364 | ≤ 0.01 | 0 |
| N | ≤ 0 | 8×10⁻⁴ |
| H | ≤ 5×10⁻⁴ | 2×10⁻⁴ |
| Fe | ≤ 0.01 | 0 |
| Ni | ≤ 0.01 | 0 |
| Si | ≤ 0.01 | 0 |
| Wresidual from ore/processing | ≤ 0.05 | 0.01 |
| Momin 99.95 % Mo excluding gases, per ASTM B386/B387 Type 361 | ≥ 99.95 (balance) | — |
Pure Mo Stress Relieved — frequently asked
What is Pure Mo Stress Relieved used for?
Pure Mo Stress Relieved is typically used for furnace hot zones and heating elements, sputtering targets and backing plates, glass-melting electrodes, semiconductor wafer boats, thermal-management heat spreaders and X-ray anodes and electronic tube components. In short: high-temp molybdenum plate.
What is the yield strength of Pure Mo Stress Relieved?
Pure Mo Stress Relieved has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 68% of refractory metal grades. Strength varies by condition: see the 7 listed tempers.
Is Pure Mo Stress Relieved easy to machine?
Not especially — machinability is rated fair (42/100, better than 97% of refractory metal grades). Machinable with sharp carbide or CBN tooling, positive rake, rigid setup and flood coolant; chips are short and brittle, edges chip easily — deburr and stress-relieve after heavy cuts, EDM and grinding work well.
Can Pure Mo Stress Relieved be welded?
Not readily — weldability is rated poor (20/100). Poor fusion weldability — electron-beam or laser welding in vacuum/high-purity inert gas only; welds recrystallize and are notch-brittle, so vacuum brazing or mechanical joining is preferred.
What surface finishes work on Pure Mo Stress Relieved?
Chemically clean/etch and vacuum-degas before use; not anodizable — apply Ni or Cr plating for aqueous corrosion, and Si/MoSi2 or Pt-based coatings for service above 500 °C in air.
Can Pure Mo Stress Relieved be formed, bent or molded?
Warm form at roughly 150–400 °C (higher for thick sections) with generous bend radii; cold bending of recrystallized or thick material causes cracking.
What is the maximum service temperature of Pure Mo Stress Relieved?
Pure Mo Stress Relieved 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.
Can FabDigit make parts in Pure Mo Stress Relieved?
Yes — Pure Mo Stress Relieved 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 B386/B386M — Molybdenum and Molybdenum Alloy Plate, Sheet, Strip, Foil, and Ribbon — ASTM (2021)
- ASTM B387 — Molybdenum and Molybdenum Alloy Bar, Rod, and Wire — ASTM (2018)
- GB/T 3876 / GB/T 4188 (2017)
- ASM Handbook Vol.2 — Properties of Refractory Metals and Alloys — ASM International (1990)
- Molybdenum — material properties and product data — Plansee SE (2023)
- Pure Molybdenum technical data — Ed Fagan Inc. / H.C. Starck Solutions (2022)
- CRC Handbook of Chemistry and Physics — thermophysical data for Mo — 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.