Refractory Metal Mo-30W-SR (Stress relieved)
Heat-treated state · default condition
ASTM B387 Grade 365 · GB MoW30
Standard commercial condition for rod, plate and machined parts: worked fibre structure retained, internal stresses removed, best balance of strength and workability.
Values for the SR condition
Other Mo-30W tempers and conditions
Mo-30W is listed in 6 conditions; see the grade overview at Mo-30W.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
PM-Sintered | Pick for large near-net blanks, crucibles, nozzles and sputter-target backing where residual porosity (typically 95–98 % of theoretical density) is acceptable. | 330 | 430 | 5 | 15 HRC | 11.9 % IACS |
Recrystallized / fully annealed | Use where dimensional stability after long high-temperature service matters (glass-contact hardware, furnace parts); softest and lowest strength, and the most brittle at room temperature. | 420 | 560 | 25 | 95 HRB | — |
hot worked / forged (thick bar, billet, rings) | Heavy sections and forged shapes (zinc pump bodies, stirrer shafts) where full wrought density and moderate strength are needed but heavy cold work is impossible. | 540 | 690 | 20 | 20 HRC | 13 % IACS |
Spheroidize annealed | Specify when very low interstitial (C, O, N) content and freedom from powder-route porosity are required, e.g. electrodes and glass-contact parts with long service life. | 580 | 720 | 22 | 21 HRC | 13 % IACS |
SRDefaultThis page Stress relieved | Standard commercial condition for rod, plate and machined parts: worked fibre structure retained, internal stresses removed, best balance of strength and workability. | 620 | 760 | 18 | 23 HRC | 100 W/m·K |
Cold worked | Choose for maximum room-temperature strength and stiffness in thin sheet, foil, wire and electrodes where no high-temperature exposure will recrystallize the part. | 950 | 1,050 | 7 | 33 HRC | — |
What is Mo-30W-SR?
Mo-30W-SR is Mo-30W heat treated to SR — standard commercial condition for rod, plate and machined parts: worked fibre structure retained, internal stresses removed, best balance of strength and workability. Mo-30W-SR has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 84% of refractory metal grades. Elongation at break is 18% and the elastic modulus is 340 GPa (49.3 Msi). Mo-30W-SR has a density of 11.9 g/cm³ (0.43 lb/in³), heavier than 73% of refractory metal grades. It melts at 2,740°C (4,964 °F).
Advantages
- Stiff — 340 GPa (49.3 Msi), better than 89% of refractory metal grades
- Low embodied carbon — 13 kg CO₂/kg, better than 87% of refractory metal grades
- High strength — 620 MPa (89.9 ksi), better than 84% of refractory metal grades
- Conducts heat well — 100 W/m·K (57.8 BTU/hr·ft·°F), better than 76% of refractory metal grades
Limitations
- Difficult to weld — 20/100, worse than 79% of refractory metal grades
- Low fracture toughness — 15 MPa·√m (13.7 ksi·√in), worse than 75% of refractory metal grades
Mo-30W-SR properties
Typical room-temperature values for Mo-30W-SR; 15 are specific to this condition. Other listed values are Mo-30W reference data and may not represent this condition. Bars are the position among refractory metal grades.
Physical3
Mo-30W-SR has a density of 11.9 g/cm³ (0.43 lb/in³), heavier than 73% of refractory metal grades. It melts at 2,740°C (4,964 °F).
Mechanical15
Mo-30W-SR has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 84% of refractory metal grades. Elongation at break is 18% and the elastic modulus is 340 GPa (49.3 Msi).
Thermal6
Mo-30W-SR is rated for continuous service to 500°C (932 °F). It conducts heat at 100 W/m·K (57.8 BTU/hr·ft·°F), better than 76% of refractory metal grades. Thermal expansion is 5 µm/m·K (2.78 µin/in·°F).
Electrical3
Mo-30W-SR conducts electricity at 13 % IACS, better than 71% of refractory metal grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 72% of refractory metal grades.
Sustainability4
Producing a kilogram of Mo-30W-SR takes about 205 MJ of energy and emits 13 kg of CO₂ — less than 86% of refractory metal grades. Typical recycled content is 20%.
Manufacturability8
Mo-30W-SR's machinability is poor (30/100, better than 54% of refractory metal grades); weldability poor (20/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Mo-30W-SR
Is Mo-30W easy to machine?
Machine with sharp, positive-rake carbide or CBN tooling, rigid setups, generous flood coolant and light finishing passes; the alloy is abrasive and notch-sensitive, and warming stock to 100–200 °C reduces chipping in drilling/tapping.
Can Mo-30W be welded?
Fusion welding (EB, laser, GTAW in high-purity argon or vacuum) is possible but the weld and HAZ recrystallize and become brittle at RT; vacuum brazing or mechanical joining is preferred for service parts.
Can Mo-30W be formed, bent or molded?
Bend, deep-draw or spin only warm (typically 200–500 °C, above the DBTT) with generous radii; cold forming of recrystallized material cracks readily.
What surface finishes work on Mo-30W?
Grind/lap or electropolish for smooth surfaces; for use above ~600 °C in air apply silicide (MoSi₂) or Si-Cr-Fe diffusion coatings, and Ni or Cr plating for aqueous/wetting control in zinc-bath hardware.
Mo-30W 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 |
|---|---|---|
| Wsolid-solution alloying addition | 28.5 – 31.5 | 30 |
| Cimpurity limit | ≤ 0.01 | 0.01 |
| Oimpurity limit, powder route | ≤ 0.01 | 0 |
| Nimpurity limit | ≤ 0 | 0 |
| Feimpurity limit | ≤ 0.01 | 0 |
| Niimpurity limit | ≤ 0.01 | 0 |
| Siimpurity limit | ≤ 0.01 | 0 |
| Mobalance, ≥ 68 % typical | balance | — |
Mo-30W-SR — frequently asked
What is Mo-30W-SR used for?
Mo-30W-SR is typically used for molten zinc pump/pipe components, glass furnace stirrers, zinc galvanizing hardware and corrosion-resistant fixtures. In short: molten-zinc resistant moly; stronger than pure molybdenum; glass-contact refractory metal.
What is the yield strength of Mo-30W-SR?
Mo-30W-SR has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 84% of refractory metal grades. Strength varies by condition: see the 6 listed tempers.
Is Mo-30W-SR easy to machine?
Not especially — machinability is rated poor (30/100, better than 54% of refractory metal grades). Machine with sharp, positive-rake carbide or CBN tooling, rigid setups, generous flood coolant and light finishing passes; the alloy is abrasive and notch-sensitive, and warming stock to 100–200 °C reduces chipping in drilling/tapping.
Can Mo-30W-SR be welded?
Not readily — weldability is rated poor (20/100). Fusion welding (EB, laser, GTAW in high-purity argon or vacuum) is possible but the weld and HAZ recrystallize and become brittle at RT; vacuum brazing or mechanical joining is preferred for service parts.
What surface finishes work on Mo-30W-SR?
Grind/lap or electropolish for smooth surfaces; for use above ~600 °C in air apply silicide (MoSi₂) or Si-Cr-Fe diffusion coatings, and Ni or Cr plating for aqueous/wetting control in zinc-bath hardware.
Can Mo-30W-SR be formed, bent or molded?
Bend, deep-draw or spin only warm (typically 200–500 °C, above the DBTT) with generous radii; cold forming of recrystallized material cracks readily.
What is the maximum service temperature of Mo-30W-SR?
Mo-30W-SR 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 Mo-30W-SR and Mo-30W-CW?
SR is the default condition — standard commercial condition for rod, plate and machined parts: worked fibre structure retained, internal stresses removed, best balance of strength and workability. CW: choose for maximum room-temperature strength and stiffness in thin sheet, foil, wire and electrodes where no high-temperature exposure will recrystallize the part. Yield strength is 620 MPa in SR versus 950 MPa in CW.
Sources
- ASTM B387 — Molybdenum and Molybdenum Alloy Bar, Rod and Wire — ASTM International (2018)
- ASTM B386 — Molybdenum and Molybdenum Alloy Plate, Sheet, Strip and Foil — ASTM International (2018)
- ASM Specialty Handbook / ASM Handbook Vol. 2 — Refractory Metals and Alloys — ASM International (1990)
- Molybdenum-tungsten (MoW30) material datasheet — Plansee SE (2023)
- Mo-30W alloy for zinc and glass industry applications — Elmet Technologies / Midwest Tungsten (2022)
- GB/T 3462 / GB/T 4181 (2017)
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.