Capabilities
Thermal Processing & Fusion Welding
High-temperature flame working, hydrogen-oxygen fusion welding, annealing, and stress-relief of fused quartz components, with leak testing reviewed when specified.
Thermal Processing & Fusion Welding of Fused Quartz
Fused quartz can be reformed, welded, and shaped by flame when the thermal process is controlled for geometry, stress, and application requirements. Tuguan Semiconductor’s flame working and annealing capabilities support complex quartz assemblies that may not be practical to machine from solid stock.
Process Capabilities
Fusion (Flame) Welding
Oxy-hydrogen flame welding joins quartz tubes, flanges, and vessels into welded assemblies. Unlike adhesive bonding or mechanical connections, fusion welds are based on the parent material, while sealing, purity, and temperature requirements should still be confirmed for the project.
| Specification | Value |
|---|---|
| He leak rate (weld seam) | Acceptance criterion defined by customer specification when leak testing is required |
| Weld joint tensile strength | Reviewed by geometry and service condition |
| Weld joint purity | Material and contamination-control requirements reviewed by application |
| Wall thickness uniformity at weld | Reviewed by drawing |
| Max tube OD | Reviewed by equipment and material form |
| Min tube wall thickness | Reviewed by tube geometry and welding route |
| Joint types | Butt weld, T-joint, flange attachment, tube-to-plate, bell end |
Process notes:
- Welding environment and cleaning route are reviewed by application cleanliness requirements
- Welds are annealed immediately after fusion to relieve thermal stress
- Leak testing can be arranged for vacuum and gas-handling components when specified
Flame Bending & Tube Forming
Straight quartz tubes can be bent, flared, necked, or formed into custom profiles using precisely controlled hydrogen-oxygen flames.
| Operation | Achievable Specification |
|---|---|
| Tube bending | Bend radius and angle reviewed by tube OD and wall thickness |
| Flaring (bell end) | Wall uniformity and OD tolerance reviewed by drawing |
| Necking (OD reduction) | OD tolerance reviewed by geometry |
| Tube-end closing (sealed ampoules) | Leak testing reviewed when specified |
| Complex manifold fabrication | Drawing-based; multiple bend + weld |
Annealing & Stress Relief
After machining, flame working, or welding, fused quartz components may contain residual stress that manifests as birefringence. High-temperature annealing in our controlled-atmosphere furnace eliminates this stress, restoring optical homogeneity and reducing risk of in-service cracking.
| Specification | Standard Anneal | Optical Grade Anneal |
|---|---|---|
| Annealing temperature | 1120°C (annealing point) | 1120°C (slow cool) |
| Cooling rate | 2–5°C/min to 500°C | 0.5–1°C/min to 500°C |
| Birefringence after | Defined by application | Defined by optical specification |
| Residual stress (photoelastic) | Reviewed by application | Reviewed by optical specification |
| Applicable materials | All quartz grades | Transparent quartz only |
Measurement: Birefringence measurement and reporting can be discussed when optical stress requirements are specified.
Flame Polishing
Flame polishing uses a diffuse hydrogen-oxygen flame to reflow the outermost surface layer of quartz — smoothing micro-cracks and improving surface finish without mechanical contact.
| Specification | Value |
|---|---|
| Surface roughness improvement | Reviewed by starting surface and application requirement |
| Applicable geometry | External surfaces of tubes, rods, plates |
| Surface purity | Cleaning route reviewed after flame polishing |
| Limitation | Not suitable for tight-tolerance surfaces unless dimensional change is acceptable |
Purity & Contamination Control in Flame Working
Quartz flame working introduces heat, and heat sources introduce potential contamination risk. Contamination-control requirements should be reviewed before quotation:
| Control Measure | Purpose |
|---|---|
| Fuel gas and torch setup | Selected based on process requirement |
| Refractory tools | Reviewed by material grade and contamination concern |
| Work bench filtration | Reviewed by cleanliness requirement |
| Post-processing ultrasonic clean | Removes surface deposits from flame operation |
| Material analysis or spot check | Can be discussed for critical orders when specified |
Typical Products Requiring Thermal Processing
| Product | Process Applied |
|---|---|
| Diffusion tubes with flanged ends | Fusion weld (tube + flange), anneal |
| Bell jars and domes | Blow forming + weld, anneal |
| U-tube heat exchangers | Multiple bends + weld manifold |
| Cleaning tanks for wet-process use | Weld assembly of plates + fittings, with chemistry reviewed by project |
| Sealed optical cells | Precision weld + leak testing when specified |
| Reactor tubes with side ports | Tube drilling + port weld + anneal |