The Application of Titanium Alloy in the Valve Industry

Titanium alloy has many advantages such as low density, high strength, corrosion resistance, high temperature and low temperature resistance, and can be widely used in many fields such as petroleum, chemical industry, marine environment, biomedicine, aerospace, automotive industry, and ships. Cast titanium alloy is obtained by casting titanium alloy into the desired shape, among which ZTC4 (Ti-6Al-4V) alloy is the most widely used, with stable process performance, good strength and fracture toughness (below 350 ℃).

As the main control component of various special environments and special fluid medium pipeline transportation systems, valves have become an important component of many equipment in production, and it can be said that any industry cannot do without valves. Due to different environmental, temperature, and medium requirements in different fields, valve material selection is particularly crucial and widely valued. Valves based on titanium alloys and cast titanium alloys have broad prospects in the field of valves due to their excellent corrosion resistance, high and low temperature performance, and high strength.

Applications

- Marine
The working environment of the seawater pipeline system is extremely harsh, and the performance of marine valves directly affects the safety and overall performance of the pipeline system. As early as the 1960s, Russia began research on titanium alloys for ships and subsequently developed them for marine use β Titanium alloy is widely used in military ship pipeline systems, including globe valves, check valves, and ball valves, with a wide variety of types and a large number of applications; At the same time, titanium valves have also been used in civilian ship pipeline systems. Compared to the previously used copper alloys, steel, etc., subsequent drainage tests have also shown that the use of cast titanium alloys has high reliability in many aspects such as structural strength and corrosion resistance, and the service life has been greatly extended, from the original 2-5 years to more than twice, which has attracted widespread attention from everyone. The three eccentric butterfly valve supplied by the China Shipbuilding 725 Research Institute in Luoyang, China for a certain model of ship is a change in the previous material selection and design scheme, using Ti80 and other materials as the main body, extending the service life of the valve to over 25 years, improving the reliability and practicality of valve product applications, and filling the technical gap in China.

- Aerospace
In the field of aerospace, cast titanium alloys also perform well, thanks to their excellent heat resistance and strength. It was also during the 1960s that American Airlines first tried titanium castings. After a period of research, titanium alloy castings have been officially applied in aircraft since 1972 (Boeing 757, 767, and 777, etc.). Not only have a large number of static structure titanium alloy castings been used, but they have also been used in critical positions, such as valve control in critical pipeline systems. Commonly used valves include safety valves, check valves, etc., which have reduced aircraft manufacturing costs and increased safety and reliability, Meanwhile, due to the relatively small density and weight of titanium alloy compared to other alloys, which is only about 60% of the same strength steel, its widespread application can promote aircraft to steadily move towards high strength and lightweight direction. At present, aerospace valves are mainly used in many control systems such as pneumatic, hydraulic, fuel, and lubrication, and are more suitable for environments with corrosion resistance and high environmental temperatures. They are one of the crucial components of aerospace vehicles, engines, and other departments. Traditional valves often require phased replacement, and may not even meet demand. At the same time, with the rapid expansion of the aerospace valve market, titanium valves are also occupying an increasing share due to their superior performance.

- Chemical Industry
Chemical valves are generally used in harsh environments such as high temperature, high pressure, corrosion resistance, and large pressure difference. Therefore, the selection of appropriate materials is crucial for the application of valve chemical industry. In the early stage, carbon steel, stainless steel, and other materials are mainly selected, and corrosion may occur after use, requiring replacement and maintenance. With the continuous development of casting titanium alloy technology and its superior performance gradually being discovered, titanium valves have also appeared in people's eyes. Taking the production unit of purified terephthalic acid (PTA) in the chemical fiber industry as an example, the working medium is mainly acetic acid and hydrobromic acid, which has strong corrosiveness. Nearly 8000 valves, including globe valves and ball valves, need to be used, with a variety of types and a large number. Therefore, titanium valves have become a good choice, increasing the reliability and safety of use. In general, due to the corrosiveness of urea, the valves at the outlet and inlet of the urea synthesis tower can meet the service life of 1 year and have already reached the usage requirements. Enterprises such as Shanxi Lvliang Fertilizer Plant, Shandong Tengzhou Fertilizer Plant, and Henan Lingbao Fertilizer Plant have made multiple attempts and ultimately chose titanium valve high-pressure check valves H72WA-220ROO-50, H43WA-220ROO-50, 65, 80, and insulation stop valves BJ45WA-25R-100, 125, etc. for the import of urea synthesis towers, with a service life of more than 2 years, demonstrating good corrosion resistance [9], reducing the frequency and cost of valve replacement.

The application of cast titanium alloy in the valve market is not limited to the above-mentioned industries, but there is good development in other aspects. For example, the new cast titanium alloy Ti-33.5Al-1Nb-0.5Cr-0.5Si developed in Japan has many advantages such as low density, high creep strength, and good wear resistance. When used in the rear exhaust valve of automotive engines, it can improve the safety performance of the engine and extend its service life.

- Other Industries
Compared to the application of cast titanium alloys in the valve industry, other applications of cast titanium alloys are more extensive. Titanium and titanium alloys have excellent corrosion resistance, which is of great significance for industries with corrosive requirements such as petrochemical industry. In these industries, many large equipment that require industrial production such as volumetric pumps, heat exchangers, compressors, and reactors will use corrosion-resistant titanium castings, which have the greatest market demand. In the field of medicine, due to titanium being a globally recognized safe, non-toxic, and heavy metal free metal, many medical assistive devices, human prostheses, and others are made of cast titanium alloys. Especially in dental medicine, almost all dental castings that have been tried out are made of industrial pure titanium and Ti-6Al-4V alloy, which have good biocompatibility, mechanical properties, and corrosion resistance. On the other hand, due to the advantages of low density and good performance of titanium and titanium alloys, they are widely used in many sports equipment such as golf clubs, ball heads, tennis rackets, badminton rackets, and fishing tackle. The products made of them are lightweight, have quality assurance, and are very popular among the public. For example, the SP-700 new titanium alloy developed by Japan Steel Pipe Company (N104) is used as a surface material for Taylor brand 300 series golf ball heads, which is best-selling in the global golf market. Since the late 20th century, cast titanium alloys have gradually formed industrialization and scale in fields such as petrochemical, aerospace, biomedical, automotive industry, and sports and leisure, from initial exploration to current vigorous promotion and development.