Precautions for Titanium Valve Selection

Titanium valves are renowned for their superior corrosion resistance, owing to the self-passivating oxide film that forms on their surface, which protects them from corrosive environments. This unique property makes titanium valves ideal for harsh working conditions where strong corrosion is a concern. However, the ability of a titanium valve to withstand corrosion largely depends on the chemical stability of this "passive oxide film" in the corrosive medium.
In neutral, oxidizing, and weakly reducing media, the passive oxide film remains stable, providing excellent protection against corrosion. For more challenging environments, such as reductive corrosive media at high temperatures or low pH, the stability of the oxide film can be enhanced through various treatments. Surface modifications, such as ion modification and anodization, can improve the corrosion resistance and surface hardness of titanium, ensuring its performance in these harsh conditions.

Limitations and Precautions for Titanium Valves

While titanium valves offer robust corrosion resistance, there are specific conditions in which their performance may be compromised:
Red Smoke Nitric Acid: Titanium valves should not be used with nitric acid concentrations above 98%, or in environments containing more than 6% free NO2.
Dry Chlorine: Titanium valves should be avoided in dry chlorine with less than 1.5% water content, as this can lead to dangerous reactions.
Pure Oxygen: Titanium valves are unsuitable for use in environments with oxygen partial pressure (PO2) greater than 35%, where natural explosions can occur.
Hydrogen Corrosion: Corrosive media containing hydrogen should be approached with caution, as titanium valves are vulnerable to hydrogen embrittlement, which can weaken the material.
Special attention must be paid to factors such as point gap and stress corrosion tendency in corrosive environments, as these can further compromise the valve's integrity.

Titanium Valve Temperature Considerations

Titanium valves are generally not recommended for use at temperatures exceeding 330°C. For higher temperature applications, it is advisable to consider temperature-resistant titanium alloys that offer enhanced performance in extreme heat.

Selecting the Right Titanium Valve Material

When selecting titanium valves, it is essential to consider the full range of operating conditions, including the working temperature, composition, concentration, and water content of the corrosive medium. Particular attention should be given to:
Point gap and stress corrosion tendencies in corrosive media.
Hydrogen embrittlement caused by titanium’s absorption of hydrogen in certain environments.
The potential for natural explosions or catastrophic failure in specific conditions.
To ensure reliable performance and avoid potential damage, titanium valves should not be used in conditions where the above factors may pose a threat.

Conclusion

Titanium valves, including titanium ball valves and gate valves, offer excellent corrosion resistance for a wide range of industrial applications. However, their suitability depends on careful consideration of the operating environment, including temperature, chemical composition, and the presence of specific corrosive agents. By understanding the limitations and potential risks associated with titanium valves, users can optimize material selection and ensure long-term, reliable performance in demanding conditions.