Quartz Glass Tubes | Fused Silica Process & Custom Tube Fabrication
Reviewed by the FGQuartz Engineering Team — 20+ years in fused silica fabrication. Last updated: September 2026.
Quick Answer: A quartz glass tube is a high-purity (SiO₂ ≥ 99.99%) fused silica cylinder used to carry gases, house wafers, or resist extreme heat and thermal shock in furnace, semiconductor, fiber optic, and laboratory equipment. FGQuartz supplies standard continuous-drawn tubes (OD 5–1000 mm, wall 0.5–20 mm+) and fully custom tubular assemblies — flanged, threaded, bent, multi-port, and welded — built to your drawings.
Key Takeaways
- Wide Dimensional Range: OD from 5 mm to large-diameter process sizes up to 1000 mm class, wall thickness 0.5–20 mm+, lengths up to 3000 mm with welded extensions.
- Six Tube Architectures: Standard, flanged, threaded, ported/manifold, bent, and fully welded multi-part assemblies.
- High-Temperature Performance: Continuous service to 1200°C, short-term to 1300°C, outstanding thermal shock resistance.
- Semiconductor & Fiber-Grade Purity: SiO₂ ≥ 99.99% with ultra-low metallic impurities.
- No Minimum Order Quantity: Standard stock cuts through fully custom welded assemblies, prototype to volume.
- Integrated Fabrication: Cutting, drilling, milling, grinding, flame forming/welding, fire polishing, and annealing under one ISO 9001 facility.
FGQuartz manufactures high-purity quartz glass tubes and custom fused silica tubular assemblies for semiconductor, solar, fiber optic, laboratory and high-temperature industrial use, supplying customers in 40+ countries since 2005. Explore large-diameter quartz tubes or browse our full product portfolio.
What Is a Quartz Glass Tube?
A quartz glass tube is a cylindrical fused silica component used wherever a process needs to carry gas, house a heating element, contain a reaction, or route material through extreme temperatures without contaminating it. Fused quartz is the default choice for this role because it combines near-zero thermal expansion (so it doesn’t crack under rapid heating/cooling), continuous service up to 1200°C, and chemical inertness that keeps the tube from reacting with or contaminating whatever passes through it.
FGQuartz quartz tubes are built for thermal shock, chemical exposure and dimensional stability in process equipment. From straight drawn cylinders to flame-welded multi-port chambers, we match OD/ID, wall, length and end features to the application — from simple diffusion furnace tubes to complex multi-port reactor assemblies.
Quartz Tube Types We Engineer
Primary tube architectures FGQuartz fabricates — from drawn stock to complex welded assemblies. The table below is a quick reference; full detail on each type follows.
| Tube Type | Best For | Key Feature |
|---|---|---|
| Standard Tubes | Diffusion furnaces, fiber preform sleeves | Continuous-drawn, controlled OD/ID and concentricity |
| Flanged Tubes | Process chambers, UHV/vacuum systems | Thermally fused or CNC-machined flanges, O-ring sealing faces |
| Threaded Tubes | Modular ultra-pure assemblies | CNC-milled external/internal threads, metal-free fastening |
| Ports & Manifolds | Gas injection, sensing in LPCVD/CVD tools | Side-arm tubes, multi-port manifolds, thermocouple sheaths |
| Bent Tubes | Compact layouts, non-straight gas/heat paths | Flame-formed bends, controlled radius and wall integrity |
| Welded Assemblies | Integrated reactor-style structures | Multi-part tube-to-tube/tube-to-plate joints, leak-tight complex geometries |
Standard Quartz Tubes
Continuous-drawn tubes with controlled OD/ID and concentricity.
• Straight process and furnace tubes
• Large-diameter processing tubes
• Heavy-wall tubes for vacuum
• Thin-wall tubing where specified
Used as diffusion furnace tubes, fiber preform sleeves and high-temperature cylinders. See also large-diameter quartz tubes.
Flanged Quartz Tubes
Tubes with thermally fused or CNC-machined flanges for mounting and sealing.
• Process chambers and furnace interfaces
• UHV and vacuum systems
• O-ring sealing faces
Common in semiconductor and industrial high-temperature equipment.
Threaded Quartz Tubes
CNC-milled external or internal threads for metal-free fastening in hot zones.
• External threading
• Internal tapping
• Custom thread forms to drawing
Suited to modular ultra-pure assemblies in high-temperature service.
Ports & Manifolds
Multi-port tubes and gas distribution assemblies.
• Side-arm and injection tubes
• Multi-port manifolds
• Thermocouple sheaths
Used for gas injection and sensing in LPCVD/CVD tools.
Bent Quartz Tubes
Flame-formed bends with controlled radius and wall integrity.
• U-shaped heater envelopes
• L-shaped routing tubes
• Custom angles and radii
For compact layouts and non-straight gas or heat paths.
Welded Assemblies
Multi-part tube assemblies joined by oxy-hydrogen welding.
• Tube-to-tube and tube-to-plate joints
• Integrated reactor-style assemblies
• Post-weld annealing
Leak-tight complex geometries under one process flow. Detail: fabrication process guide.
Typical Specifications of Quartz Tubes
Baseline specifications for FGQuartz high-purity quartz tubes. Critical dimensions and tolerances are set from your drawings. Full material data: Technical Specifications.
1. Dimensional & Machining Range
| Parameter | Typical Range | Notes |
|---|---|---|
| Outer Diameter (OD) | 5 mm – 1000 mm | Large-diameter process tubes available |
| Wall Thickness | 0.5 mm – 20 mm+ | Heavy-wall options for vacuum service |
| Length | Up to 3000 mm (standard) | Longer runs via welded sections when required |
| Concentricity / Bow | Tight control (e.g. < 0.1 mm/m class where specified) | Important for automated process equipment |
2. Material Purity (Fused Silica)
| Property | Typical Value |
|---|---|
| SiO₂ Purity | ≥ 99.99% |
| Metallic Impurities | Ultra-low (semiconductor and fiber grades) |
| Material Type | High-purity fused silica / synthetic quartz |
| Available Optical Grades | Standard clear, UV-grade, IR-grade, opaque |
3. Thermal & Physical Performance
| Property | Typical Value |
|---|---|
| Continuous Operating Temp. | Up to 1200°C |
| Short-term Maximum Temp. | Up to 1300°C |
| Softening Point | Approx. 1680°C |
| Coefficient of Thermal Expansion | Approx. 5.5 × 10⁻⁷ /°C |
| Thermal Shock Resistance | Outstanding |
Note: Baseline values. Final tolerances and features are confirmed in DFM review.
How Quartz Tubes Are Fabricated
FGQuartz converts stock tubing into application-ready components — from length cuts to multi-chamber welded assemblies.
Precision Cutting & Chamfering — Diamond cutting brings tubes to length; edges are chamfered or fire-polished to reduce the micro-cracks that can propagate under thermal cycling.
Diamond Core Drilling — Ports for gas, sensors, and exhaust are drilled without the uncontrolled fracture that conventional drilling would cause in brittle fused silica.
CNC Milling & Slotting — Locating grooves, steps, and interfaces are milled for mating with boats, fixtures, or other assembly components.
Centerless Grinding — Achieves tight OD control for seals and mating parts where a standard drawn tolerance isn’t sufficient.
Flame Forming & Welding — Oxy-hydrogen torches create bends, flanges, side ports, and vacuum-capable joints, allowing complex geometries to be built from straight stock.
Fire Polishing & Annealing — A final flame pass heals machining marks on the surface, followed by controlled annealing to relieve internal stress before the part goes into service.
More on cold processing and thermal processing.
Quartz Tubes vs. Alternative Tube Materials
Fused quartz is the default choice for high-temperature process tubing, but borosilicate glass, ceramic, and metal alloy tubes are used in specific process windows.
| Material | Max Temp | Contamination Risk | Typical Use |
|---|---|---|---|
| Fused Quartz | 1200°C (short-term 1300°C) | Very low (chemically inert, transparent) | Diffusion, LPCVD, fiber optics, lab equipment |
| Borosilicate Glass | ~500°C | Low, but limited by lower purity | General lab glassware, low-temp process tubing |
| Alumina Ceramic | ~1750°C | Low, opaque, reacts with some fluxes | Extreme high-temp furnace tubes |
| Stainless Steel / Inconel | ~1100°C (alloy-dependent) | Metallic ion contamination risk | Structural furnace shells, non-purity-critical piping |
Quartz remains the standard for semiconductor, fiber optic, and analytical applications where visual process monitoring (via transparency) and freedom from metallic contamination outweigh the need for extreme temperature ceilings. For processes exceeding quartz’s practical service range, alumina ceramic or high-temperature alloys are typically specified instead.
Applications of Quartz Tubes
Semiconductor
• Diffusion and oxidation furnace tubes
• LPCVD / PECVD liners and chambers
• Flanged and multi-port injection tubes
See Semiconductor Quartz.
Solar PV
• Large-format diffusion tubes (e.g. POCl₃ lines)
• PECVD process tubes and liners
• Exhaust and gas delivery tubing
See Solar PV Quartz.
Fiber Optics
• MCVD / VAD substrate tubes
• Preform jacketing and overcladding tubes
• Lathe-related quartz components
See Fiber Optic Quartz.
Laboratory & Industrial
• IR heater envelopes
• Reaction and combustion tubes
• Thermocouple protective sheaths
See Laboratory Quartz and High-Temperature Quartz.
How to Choose the Right Quartz Tube for Your Application
Use this three-step framework to specify the right tube before requesting a quote:
- Identify your process function. Simple heat/gas containment favors a standard drawn tube; sealing to equipment favors a flanged tube; modular assembly favors threading; gas injection or sensing favors a ported/manifold design.
- Confirm dimensional and thermal requirements. Specify OD, ID or wall thickness, length, and peak operating temperature. Vacuum or UHV service typically calls for heavier wall thickness and flanged, O-ring-sealed ends.
- Decide standard vs. custom. If your equipment interface requires bends, welded ports, or non-standard dimensions, plan for a custom assembly — FGQuartz accepts single-piece prototype orders with no MOQ.
Send OD/ID, wall, length, and end features (flange, thread, ports) or full CAD to our engineering team for a feasibility review.
Quartz Tube Pricing: What Drives the Cost?
Quartz tube pricing depends on four main factors:
- Diameter and wall thickness — large-diameter or heavy-wall tubes require more raw material and processing time than standard thin-wall stock.
- End features — a plain cut length costs far less than a flanged, threaded, or multi-port welded assembly.
- Tolerance requirements — tight concentricity, bow, or OD/ID control (via centerless grinding) adds processing steps beyond standard drawn tolerance.
- Order volume — unit pricing improves at higher volumes, though FGQuartz accepts single-piece prototype orders with no MOQ.
For an accurate quote, send your dimensions, end features, and any drawings to our engineering team — quotations are typically returned within 24 business hours.
Quality Assurance & Handling Guidance
Every FGQuartz tube is checked against approved drawings for OD/ID, wall thickness, concentricity, and end-feature accuracy under our ISO 9001 quality system.
In-service handling tip: Clean tubes with an acid bath or alcohol wipe before high-temperature use to remove surface contaminants such as alkali salts and fingerprints, which act as catalysts for devitrification (surface crystallization) above roughly 1150°C. For large-diameter or thin-wall tubes, support the full tube length during handling and installation to avoid point-load stress on the brittle material.
Why Choose FGQuartz
• Fused silica tube and assembly experience since 2005
• CNC machining, flame welding and annealing under one ISO 9001 facility
• Semiconductor- and fiber-oriented purity grades
• Prototype to volume / OEM supply, no minimum order quantity
• Build-to-print from customer CAD
• Global reach: export experience to 40+ countries with full compliance documentation
• Matching range: boats, crucibles, rods
Frequently Asked Questions
After drawing approval, many custom tubes and simple assemblies are completed in about 3–6 weeks, depending on diameter, features and factory load. Single prototypes are accepted.
Provide outer diameter, inner diameter or wall, length, end finish (open, sealed, flange, thread, ports), operating temperature and chemistry if known, quantity and drawings. CAD formats such as DXF, STEP, IGES or PDF are preferred.
Yes. High-purity quartz process tubes are widely used as diffusion, oxidation and CVD/LPCVD chamber tubes where chemical purity and thermal stability are required. Matching boats, injectors and liners are specified as separate components.
Standard supply is high-purity fused silica with SiO₂ typically ≥ 99.99%. Clear, UV-oriented, IR-oriented and opaque grades are available. Low-OH or fiber-process grades can be quoted when the application is specified.
Yes. Flanges, side ports, multi-port manifolds, bent sections and tube-to-tube welded assemblies are produced by CNC machining and oxy-hydrogen flame welding, followed by annealing when required.
Continuous service is typically up to about 1200 °C, with short-term peaks near 1300 °C depending on geometry and atmosphere. The softening point of fused silica is approximately 1680 °C. Exact limits depend on wall thickness, load and chemistry.
Typical outer diameter ranges from about 5 mm to large process sizes up to the 1000 mm class where specified. Wall thickness typically ranges from about 0.5 mm to 20 mm or more. Lengths up to about 3000 mm are common; longer pieces can use welded sections.
FGQuartz manufactures continuous-drawn standard quartz tubes and custom tubular parts, including large-diameter process tubes, heavy-wall vacuum tubes, flanged tubes, threaded tubes, multi-port tubes, bent tubes and welded assemblies.