MOLYBDENUM ROD / SHAFT
Molybdenum rod and shaft
Ø0.5–300mm | Mo ≥99.95% | Density ≥10.15 g/cm³ | Ground / turned / forged
WeiBeam · Electrode solutions for high-temperature melting
Molybdenum rods and shafts are two diameter bands of the same material family: roughly 0.5–25mm is drawn or hot-swaged and usually called shaft; 16–100mm relies on forged billet, with larger diameters supplied as sintered powder stock and usually called rod. Both serve the same core duties: vacuum electronic parts, guide rods, support electrodes, lead wires and furnace heating elements. Acceptance priorities differ between slim and heavy sections. Shafts are judged on straightness as well as diameter tolerance, typically about 2.0mm per meter in the ground condition, because assembly offset affects alignment and the temperature field; rods are judged on structural density and internal defects, with oxide skin and light forging marks acceptable on forged surfaces, while precision duties can be delivered turned or ground.
In terms of grade, Mo1 is ductile and general-purpose; MoLa uses lanthanum oxide dispersion to raise recrystallization temperature and creep resistance; TZM offers higher high-temperature strength. Rods and electrodes are often used together in fiberglass furnaces. A practical order is: diameter from application, tolerance from assembly, grade and surface from duty.
In high-temperature melting and thermal-field systems this part is often used alongside electrodes elsewhere in the line. We recommend selecting them together against furnace structure, assembly method and working temperature to reduce thermal-expansion mismatch between different materials.
FEATURES
Molybdenum rod and shaft — key features
Core characteristics for furnace conditions and operating requirements.
Full diameter range
Ø0.5–25mm drawn or swaged shaft, 16–100mm forged rod, sintered stock to about 300mm.
Full grade range
Mo1, MoLa and TZM matched to temperature, life and machinability.
Controlled surface and tolerance
Ground, turned or forged black surface; ground straightness controlled to ≤2.0mm/m.
Inspection available
Ultrasonic inspection to JB/T 4730 or by agreement, with a mill certificate.
SPECIFICATIONS
Specification data
This product is accepted to the relevant material standard or a mutual technical agreement, with key dimensions, density and material inspected batch by batch. Special sizes can be machined to drawing.
| Parameter | Specification |
|---|---|
| Form | Shaft (drawn / swaged) / rod (forged / sintered) |
| Diameter | Ø0.5–25mm (shaft); Ø16–100mm (forged rod); sintered stock to about 300mm |
| Forming | Drawing, hot swaging, forging, powder sintering |
| Grades | Mo1 / MoLa / TZM |
| Molybdenum content | ≥99.95% |
| Density | ≥10.15 g/cm³ |
| Standard | ASTM B387 / GB/T 17792 |
| Surface | Ground / turned / electro-cleaned / forged black |
| Straightness | Ground shaft ≤2.0mm/m (by size and agreement) |
| Typical uses | Vacuum electronic lead wires, guide rods, support electrodes, heating elements, high-temperature structural parts |
Material and physical properties
| Parameter | Typical value / note |
|---|---|
| Available grades | Mo1 (pure Mo) / MoLa (lanthanum-doped) / TZM (Ti-Zr-Mo) / Mo-Zr ODS |
| Molybdenum content | ≥99.95% (higher purity by technical agreement) |
| Density | ≥10.2 g/cm³ (varies slightly by grade and condition) |
| Melting point | ≈2620–2623 °C |
| Resistivity (20 °C) | ≈0.053 µΩ·m |
| Conductivity | ≥30% IACS |
| Thermal expansion | ≈5.25×10⁻⁶/°C |
| Elastic modulus | ≈315 GPa |
| Hardness | ≥85 HRB (by grade and condition) |
| Standards | Accepted to the relevant material standard or a mutual technical agreement |
| Factory inspection | Spectral composition, density, metallography, ultrasonic inspection, dimensions and appearance |
| Delivery documents | Mill certificate with full batch traceability |
Typical values for pure molybdenum. MoLa, TZM and special sizes follow the mutual technical agreement and the test report supplied with each batch.
FAQ
Common questions
Selection, customization and quotation questions.
How do rod and shaft differ?
The industry generally distinguishes by diameter and forming: about 0.5–25mm is drawn or swaged and called shaft; above 16mm relies on forging or sintering and is called rod. The boundary is not a mandatory standard, so specifying diameter, tolerance and surface condition is more precise.
What straightness can a ground shaft achieve?
Ground shafts are normally controlled to about 2.0mm per meter, depending on diameter, length and processing. For guide rods and support electrodes, specify both per-meter deviation and total bend limits on the drawing.
Is a dark forged rod surface normal?
Yes. Forged surfaces carry an oxide skin and light hammer marks, which are acceptable conditions. For precision assembly or clean duties, specify turned or ground delivery and agree surface acceptance in the contract.
CUSTOM
Selection and quotation
Share your furnace structure and process conditions. Our engineers will help select the right electrode and you can request a standard-size sample. We support export customers worldwide with remote technical coordination.