RAYCHIN LIMITED

Tantalum Screws – Complete Product Range

Critical Applications of Tantalum Screws

International Standards & Global Designations – Tantalum Screw Materials

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

Chemical Composition (Weight %) – Tantalum Alloys for Screws

Our Tantalum screws are produced from material conforming to the limits of applicable ASTM, AMS, and ASME standards. High‑purity grades available up to 99.99% (4N).

Pure Tantalum (UNS R05200 / R05400) – ASTM B365 / F560

Tantalum-Tungsten Alloys (Ta2.5W / Ta10W) – ASTM B365

Metallurgical note: Tantalum is a body-centered cubic (BCC) refractory metal with a melting point of 2996°C, second only to tungsten and rhenium. It is highly ductile and can be cold worked extensively without intermediate annealing. Tantalum derives its exceptional corrosion resistance from a stable, adherent pentoxide (Ta₂O₅) film that forms spontaneously in air or oxidizing media. This oxide film is self‑healing if damaged and protects the underlying metal from attack by all common acids except hydrofluoric acid. Tantalum is also completely biocompatible and non‑toxic, making it ideal for medical implants. Tungsten alloying additions (2.5% or 10%) increase strength, creep resistance, and recrystallization temperature while maintaining good fabricability. The density of tantalum (16.6 g/cm³) is approximately twice that of steel, providing a substantial feel and high mass in miniature screw applications.

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

Tantalum screws are supplied in appropriate conditions (annealed, stress relieved, or as‑worked) per ASTM B365 and customer specifications. Data represent typical values based on industry standards.

Pure Tantalum (R05200) – Mechanical Properties

Tantalum Alloys – Mechanical Properties

High‑Temperature Mechanical Properties – Pure Tantalum (representative)

Physical Properties – Tantalum

High‑Temperature Performance of Tantalum Screws

Tantalum is one of the most refractory metals, with a melting point of 2996°C (5425°F), exceeded only by tungsten and rhenium. This exceptional high‑temperature capability makes tantalum screws ideal for extreme thermal environments. Tantalum maintains useful mechanical properties at temperatures exceeding 2000°C in vacuum or inert atmospheres. It exhibits excellent creep resistance and thermal stability. Tantalum‑tungsten alloys (Ta-10W) offer significantly higher strength at elevated temperatures and are used for fasteners in high‑temperature furnaces, rocket engines, and jet propulsion systems. Tantalum's low vapor pressure ensures no contamination of vacuum environments, making it essential for vacuum furnace hot zones and semiconductor processing equipment. The coefficient of thermal expansion (6.5 × 10⁻⁶/K) is low and matches well with many ceramic and refractory materials, reducing thermal stress in high‑temperature assemblies.

Elevated Temperature Capabilities

*Note: Tantalum oxidizes rapidly in air above 260-300°C. For high‑temperature air applications, protective coatings are required. Tantalum is primarily used in vacuum, inert gas, or reducing atmospheres at elevated temperatures.

Exceptional Corrosion Resistance of Tantalum Screws

Tantalum is renowned for its outstanding corrosion resistance, approaching that of glass in many aggressive media. It is virtually immune to attack by most acids and chemical compounds below 150°C. The protective Ta₂O₅ oxide film (thickness 2-5 nm) is stable, adherent, and self‑healing if damaged. Tantalum's corrosion resistance often exceeds that of noble metals like platinum at a fraction of the cost. Tantalum screws provide reliable fastening in the most aggressive chemical environments.

• Hydrochloric Acid: Tantalum is completely resistant to hydrochloric acid at all concentrations and temperatures up to 110°C (boiling). Even above 110°C, corrosion rates remain extremely low (0.0004 mm/year at 150°C).
• Sulfuric Acid: Excellent resistance up to 150°C at all concentrations. At 175°C in concentrated sulfuric acid, corrosion rate is only 0.0004 mm/year. In fuming sulfuric acid (15% SO₃) at 130°C, corrosion rate is 15.6 mm/year.
• Nitric Acid: Completely resistant at all concentrations and temperatures up to boiling.
• Phosphoric Acid: Excellent resistance up to 150°C. At 250°C in 85% phosphoric acid, corrosion rate is approximately 20 mm/year.
• Aqua Regia: Completely resistant at all temperatures up to boiling.
• Organic Acids: Completely resistant to all organic acids, including acetic, formic, and citric acids.
• Halogens: Resistant to chlorine, bromine, and iodine up to 150°C in dry conditions. Moist halogens can attack tantalum.
• Alkalis: Tantalum is attacked by strong alkalis. In 40% NaOH at 110°C, dissolution is rapid. In KOH solutions, attack occurs above 100°C.
• Hydrofluoric Acid: Tantalum is rapidly dissolved by hydrofluoric acid (HF) and by mixtures containing HF (such as HF/HNO₃). This is the primary acid that attacks tantalum.
• Hydrogen Embrittlement: Standard tantalum is susceptible to hydrogen embrittlement in strongly reducing acid environments. Special alloys (ULTRA 76 Plus, Ta-2.5W-0.15Ru) reduce hydrogen pickup by up to 100 times, eliminating the need for platinum protection.

Tantalum's corrosion resistance is superior to that of stainless steels, nickel alloys, titanium, and zirconium in most reducing acid environments. It is the material of choice for critical applications where long‑term reliability in aggressive chemical environments is essential.

Manufacturing Standards – Tantalum Screws

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

We offer surface finishes: plain (as‑machined), chemically cleaned, passivated, and electropolished. Tantalum screws can be supplied with certified material traceability, dimensional inspection reports, and mechanical test certificates. Our manufacturing processes include CNC heading, thread rolling, and precision machining to achieve tight tolerances. We specialize in custom configurations including non‑standard lengths, special head styles, and proprietary thread forms. Cleanroom packaging available for medical 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.