STREAM MOUTH
Molybdenum stream mouth
Common (120–200)×(250–300)mm | Tolerance ±0.5mm | Mo ≥99.95% | Density ≥9.5 g/cm³
WeiBeam · Electrode solutions for high-temperature melting
The molybdenum stream mouth is the discharge nozzle at the end of the forehearth in fiberglass, aluminosilicate fiber and building-material melting equipment. After refining and homogenizing, glass melt is guided through the forehearth and stream mouth into a platinum-rhodium bushing, then drawn through orifices by the winder. Temperature and flow stability at the mouth directly affect the melt entering the bushing. The part operates at 1600–1700 °C while its outer surface sees an oxidizing atmosphere, so service life depends mainly on oxidation protection. Two routes are common: a water-cooled design with a helical copper coil, and a water-free design with an external protective sleeve. Water cooling is versatile but can create hot spots at the cone and transition radii; the water-free design replaces cooling with physical oxygen isolation, simpler in system terms but more demanding on sleeve material, fit tolerances and thermal-expansion matching.
The stream mouth belongs to the same glass-furnace molybdenum family as electrodes and threaded parts, so material and assembly can be considered together. We machine to drawings, commonly in the (120–200)×(250–300)mm range with tolerances within ±0.5mm, and can supply material certificates and dimensional records.
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 stream mouth — key features
Core characteristics for furnace conditions and operating requirements.
High-temperature erosion resistance
Mo ≥99.95%, density ≥9.5 g/cm³, stable in 1600–1700 °C melt service.
Two oxidation-protection designs
Water-cooled copper coil or water-free external sleeve, chosen for the furnace.
Controlled flow path
Upper cylinder plus lower cone, with a bottom cone forming slow-flow, contraction and drip stages.
Machined to drawing
Built to interface dimensions, tolerances and connections, including threaded, welded or inset assembly.
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 |
|---|---|
| Application | Discharge nozzle for fiberglass, aluminosilicate fiber and building-material melting |
| Common size | (120–200)×(250–300)mm (custom to drawing) |
| Tolerance | ±0.5mm |
| Molybdenum content | ≥99.95% |
| Density | ≥9.5 g/cm³ |
| Service temperature | 1600–1700 °C |
| Structure | Upper cylinder + lower cone + bottom nozzle; optional flow guide and ribs |
| Oxidation protection | Water-cooled / water-free (external sleeve) |
| Reference standard | Accepted to technical agreement and drawing (material, dimensions, density) |
| Surface | Silver-grey metallic luster, no water absorption, no oil impregnation |
| Delivery documents | Material certificate, dimensional records (on request) |
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.
Water-cooled or water-free stream mouth — how to choose?
For continuous high-load furnaces, evaluate the water-free design first to reduce water-line maintenance and interruption risk. Retrofit projects with a reliable water system can retain water cooling. Confirm with the furnace drawing, glass type, melt temperature and daily throughput.
What are the common sizes and tolerance?
Common sizes are (120–200)×(250–300)mm with tolerances within ±0.5mm. Interface dimensions and connections vary widely between furnaces, so please provide a drawing.
What should I watch during installation?
The mouth is generally not adjusted after installation. Avoid striking the cone during assembly, follow the furnace heating and cooling curves, and avoid local thermal shock. In service, monitor flow stability and cone condition, and plan replacement if flow fluctuates, the cone builds up or the outer wall starts to flake.
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.