Top China Quartz Furnace Tube Manufacturer & Supplier

Under continuous isothermal operation in an inert, oxidizing, or vacuum atmosphere, standard high-purity clear fused quartz tubes comfortably operate at 1100°C to 1150°C. For intermittent or short-duration duty cycles (such as rapid thermal annealing), tubes can reach 1300°C. The physical softening point of pure amorphous vitreous silica is approximately 1683°C, while the annealing point is 1215°C and the strain point is 1120°C. Prolonged operation above 1150°C without adequate internal support can cause sagging, especially in horizontal furnace designs under heavy wafer-boat payloads.

White haze on quartz is the outward manifestation of α-cristobalite phase crystallization. It is initiated by three primary factors: (1) Surface contamination from alkali elements (e.g., sodium and potassium from fingerprints, dust, or tap water); (2) Extended thermal soaking above 1050°C; and (3) Water vapor in the heating chamber. To prevent premature devitrification: always handle tubes with lint-free polyethylene gloves, perform an initial acid etch clean using a 5%–10% electronic-grade hydrofluoric (HF) acid bath followed by deionized (DI) water rinsing, and ensure thorough drying before thermal ramping.

Hydroxyl radicals bond into the amorphous network as silanol groups (Si-OH), directly disrupting the robust Si-O-Si matrix. Higher OH concentrations (common in gas-melted quartz at 150–200 ppm) drastically lower the high-temperature viscosity of the glass, shifting the softening and annealing points downward by up to 80°C. For semiconductor diffusion and LPCVD tubes operating above 1100°C, we apply secondary vacuum dehydroxylation to maintain OH content below 10 ppm (or sub-2 ppm upon request), significantly stiffening the tube and preventing gravitational sagging over thousands of thermal hours.

Yes. Custom fabrication based on customer drawings is our core specialty. Our master lampworkers use automated glass lathes and hydrogen-oxygen burners to fabricate: precision optical ground flat flanges, ISO/KF/CF vacuum flanges with fluoroelastomer O-ring grooves, ground spherical ball-and-socket joints, single/multi gas injection manifolds, integrated internal thermocouple wells, spiraled cooling jackets, and reduction junctions. We routinely manufacture tubes ranging from 2mm to 450mm Outer Diameter (OD) with lengths up to 3000mm.

Standard drawn tubing typically maintains OD and wall thickness tolerances of ±0.5mm to ±1.0mm depending on diameter. However, for precision semiconductor furnace tubes, we execute secondary CNC mechanical grinding, ultrasonic boring, and precision fire-polishing to achieve:

• Outer Diameter (OD) Tolerance: Down to ±0.15 mm
• Wall Thickness Uniformity: Within ±0.10 mm
• Straightness / Total Run-Out (TIR): < 1.0 mm per meter length
• Ovality (Out-of-Roundness): < 0.5% of nominal OD

We have engineered a multi-tier protective packaging system refined through thousands of overseas shipments. Each tube is thoroughly cleaned, capped with protective end seals, enclosed in high-grade anti-static bubble wrap, and nestled inside a custom-molded high-density EPE shock-absorbing foam cradle. The entire assembly is then encased within a heavy-duty, fumigated plywood crate equipped with internal impact dampeners, shock-watch monitors, and tilt indicators. We maintain a documented export break-free transit rate exceeding 99.7%. In the rare event of transit damage, full replacement items are dispatched immediately under our transit warranty.

For standard stocked diameter tubes requiring straightforward cutting and end fire-polishing, dispatch occurs within 24 to 48 hours. Custom prototype tubes involving laser drilling, complex bending, or flanged welding typically ship within 5 to 10 working days following CAD drawing sign-off. High-volume manufacturing batch orders (50 to 500+ units) generally require 15 to 25 working days, supported by express air freight (DHL, FedEx, UPS, air cargo) or consolidated ocean shipping (FOB, CIF, DDP).

Fused quartz possesses near-complete chemical inertia to almost all acids—including concentrated hydrochloric acid (HCl), nitric acid (HNO₃), sulfuric acid (H₂SO₄), and aqua regia—even at elevated temperatures up to 800°C. The only notable exceptions are Hydrofluoric Acid (HF), which aggressively dissolves SiO₂ at any temperature, and Phosphoric Acid (H₃PO₄) above 150°C. Furthermore, concentrated alkaline solutions (NaOH, KOH) will slowly etch vitreous quartz at ambient temperatures and rapidly corrode the material at elevated temperatures.