RAYCHIN LIMITED

Titanium Vented Screws – Complete Product Range

Critical Applications of Titanium Vented Screws

International Standards & Global Designations – Titanium Vented Screw Materials

RAYCHIN LIMITED manufactures Titanium vented screws from material conforming to the most widely used national and international specifications. All material is traceable to the mill.

Chemical Composition (Weight %) – Titanium Alloys for Vented Screws

Our Titanium vented screws are produced from material conforming to the limits of applicable ASTM, AMS, and ISO standards. High‑purity grades available for medical and semiconductor applications.

Commercially Pure Titanium (Grades 1-4) – ASTM B348 / F67

Titanium Alloys – ASTM B348 / F136

Metallurgical note: Titanium is an allotropic element with a hexagonal close-packed (α) structure at room temperature, transforming to body-centered cubic (β) at 882°C. CP grades are α-phase, while alloying with aluminum stabilizes α-phase, and vanadium/molybdenum stabilize β-phase. Ti-6Al-4V is an α+β alloy combining high strength with good ductility. The natural oxide layer (TiO₂) is 2-5 nm thick, self‑healing, and responsible for titanium's exceptional corrosion resistance. Titanium is non‑magnetic with magnetic permeability <1.00005, essential for vacuum and beamline applications.

Complete Mechanical & Physical Properties – Titanium Alloys for Vented Screws (MPa / ksi)

Titanium vented screws are supplied in appropriate conditions (annealed for CP grades, solution treated and aged for Grade 5) per ASTM B348, ASTM F136, and customer specifications. The venting channel (coaxial or slot) does not significantly affect mechanical properties due to precision machining techniques that maintain thread integrity.

Commercially Pure Titanium – Mechanical Properties (minimum values)

Titanium Alloys – Mechanical Properties (minimum values)

High‑Temperature Mechanical Properties – Ti-6Al-4V (typical values)

Note: Titanium vented screws can be baked to 250°C for UHV preparation. Prolonged exposure above 300°C may cause oxidation; protective coatings recommended above 500°C.

Physical Properties – Titanium

High‑Temperature Performance of Titanium Vented Screws

Titanium alloys retain significant strength at elevated temperatures up to 500°C, making them suitable for high-temperature vacuum applications. Ti-6Al-4V maintains useful mechanical properties up to 315°C (600°F) for extended service, and up to 500°C (932°F) for short-term exposure. The alloy exhibits excellent creep resistance at moderate temperatures. For UHV applications, titanium vented screws can be repeatedly baked to 250°C for vacuum conditioning without degradation. However, titanium becomes increasingly reactive with oxygen above 500°C, forming an oxygen-enriched brittle α-case layer that degrades fatigue life. For applications above 500°C, protective coatings (such as TiAlN) or high-temperature alloys (Ti-6242, Ti-1100) are recommended. Titanium's melting point (1660°C) is higher than steel, but oxidation limits practical use in air.

Elevated Temperature Capabilities

Note: Titanium alloys are susceptible to "alpha case" formation above 500°C in air, which embrittles the surface. All vented screws are precision cleaned to remove surface contaminants before packaging.

Exceptional Corrosion Resistance of Titanium Vented Screws

Titanium is renowned for its outstanding corrosion resistance in a wide range of environments, often exceeding that of stainless steels and nickel alloys. The protective TiO₂ oxide film (2-5 nm thick) is stable in oxidizing media and rapidly self‑heals if damaged. Titanium is virtually immune to pitting, crevice corrosion, and stress corrosion cracking in chloride environments up to 200°C. For vacuum applications, the oxide layer provides a stable, low-outgassing surface that meets UHV requirements.

• Seawater / Marine: Titanium is completely resistant to seawater up to 120°C. Corrosion rate <0.01 mm/year in flowing seawater, with no measurable attack after decades of immersion. Immune to crevice corrosion in ambient seawater.
• Chlorides: Excellent resistance to chlorides, hypochlorites, and chlorine dioxide. Essential for semiconductor etch chambers using chlorine-based plasmas.
• Nitric Acid: Outstanding resistance up to boiling temperatures at all concentrations. Corrosion rate <0.1 mm/year.
• Acetic Acid: Excellent resistance at all concentrations and temperatures up to boiling.
• Sulfuric Acid: CP titanium resistant up to 5% at boiling, 10% at ambient. Grade 7 (Pd) extends resistance to 40% at boiling.
• Hydrochloric Acid: CP titanium resistant up to 3% at boiling, 8% at ambient. Grade 7 extends to 20% at ambient, 7% at boiling.
• Phosphoric Acid: CP titanium resistant up to 20% at ambient. Grade 7 extends to 40% at ambient, 10% at boiling.
• Organic Acids: Completely resistant to all organic acids, including formic, citric, and tartaric acids.
• Alkalis: Resistant to dilute alkalis at ambient. Attacked by concentrated hot alkalis.
• Halogens: Resistant to wet chlorine gas and chlorine solutions up to 200°C. Not recommended for dry chlorine above 200°C.
• Hydrofluoric Acid: Rapidly attacked by HF and fluoride-containing media – not recommended.
• Galvanic Corrosion: Titanium is cathodic to most metals; can accelerate corrosion of active metals (steel, aluminum) in contact. Isolation or coating recommended.
• Hydrogen Embrittlement: Titanium can absorb hydrogen in certain conditions (cathodic charging, acid pickling). Grades with Pd or Ru reduce hydrogen pickup.
• Outgassing Performance: Titanium's stable oxide layer provides total outgassing rates <10⁻⁹ Torr·L/s·cm² after proper cleaning and bakeout, meeting UHV requirements for pressures below 10⁻¹⁰ Torr.

Manufacturing Standards – Titanium Vented Screws

All Titanium vented screws are manufactured and tested to meet the following standards:

We offer precision cleaning options: Standard Clean (degreased), Vacuum Clean (UHV-ready, Class 100 cleanroom packaged), and Special Clean (custom protocols per customer specification). All vented screws are machined with precision venting channels (coaxial or slot) using micro-drilling techniques that maintain thread integrity. Surface finishes available: plain (as‑machined), passivated, anodized. Titanium vented screws can be supplied with certified material traceability, dimensional inspection reports, and mechanical test certificates. Our manufacturing processes include CNC heading, micro-drilling, thread rolling, and heat treatment (solution treat and age for Grade 5). We specialize in custom configurations including non‑standard lengths, special vent configurations, and proprietary drive types. Cleanroom packaging available for UHV and semiconductor applications. All screws supplied with EN 10204 Type 3.1 or 3.2 certification. ISO 9001:2015 and AS9100D certified quality management system.