How Does Titanium Alloys Work in Marine Valves?

Marine valves are the core of fluid control on ships, which are related to navigation safety and economy. The harsh marine environment imposes stringent requirements on their materials. Traditional materials are prone to failure and require frequent maintenance, making them unable to meet the development needs of modern ships. Titanium alloys have become the preferred choice for high-end marine valves due to their excellent properties, and their application advantages have been verified in marine engineering practices.

 

 

 

Corrosion resistance is the core advantage of titanium alloy marine valves. The titanium dioxide passivation film on their surface can isolate corrosive media. The seawater corrosion rate of domestic Ti31 titanium alloy is only 1/10 that of 316L stainless steel, and its corrosion resistance is far superior to traditional marine metals.

 

Ti31 contains elements such as Mo and Ni, which gives it strong resistance to stress corrosion and crevice corrosion. Its galvanic corrosion rate when matched with ship pipelines is extremely low, enabling it to serve without complex anti-corrosion measures. This completely solves the problems of corrosion leakage and short service life of traditional valves.

 

 

Titanium alloy marine valves can help ships save energy, reduce consumption and optimize structures. Titanium alloys have low density and excellent mechanical properties. The tensile strength of Ti31 titanium alloy is twice that of 316L stainless steel, which can adapt to the dynamic loads and high-pressure working conditions of valves. Under the same strength condition, titanium alloy valves are 30%-40% lighter than stainless steel valves and have excellent high-pressure bearing performance.

 

The lightweight design brings full-life-cycle advantages: it can reduce ship displacement, lower the energy consumption of hydraulic systems by about 10%, reduce the labor intensity of valve installation and disassembly, adapt to the lightweight and narrow-space maintenance needs of ships, and cut down operation and maintenance costs. The high-strength characteristic of titanium alloys can also simplify the design of valve wall thickness and reduce material consumption, achieving both lightweight and reliability improvement.

 

 

The machinability of titanium alloys can be optimized through technological processes to improve the manufacturing accuracy and adaptability of marine valves. It can meet the processing requirements of various types of valves such as gate valves and butterfly valves, as well as customized complex flow channels and sealing structures. Titanium alloys have excellent hot workability. Multi-stage temperature-controlled forging can refine grains and optimize the microstructure. Annealing at 750℃ for 1 hour followed by air cooling can eliminate internal stress, ensuring that the hardness of the material's entire cross-section is ≤250HB and guaranteeing dimensional accuracy.

 

For welding, titanium alloys are compatible with methods such as TIG welding and plasma welding. The post-welding strength coefficient exceeds 90%, and no complex post-weld heat treatment is required, which can avoid welding defects and ensure the sealing performance and structural strength of key parts. Meanwhile, low-oxygen MT-Ti31 titanium alloy powder developed by enterprises such as AVIC Metal Technology Co., Ltd. can realize the forming of thin-walled valves with complex flow channels through SLM additive manufacturing technology, with wall thickness accuracy reaching ±0.1mm.

 

 

Titanium alloys are suitable for the complex working conditions of marine valves. They can withstand polar low temperatures, tropical high temperatures and the day-night temperature differences at sea, and resist dynamic loads such as seawater impact and vibration. They have a wide operating temperature range, maintaining excellent mechanical properties and corrosion resistance between -253℃ and 550℃.

 

At low temperatures, their strength increases, toughness is good and there is no risk of brittle fracture, making them suitable for polar ships. At high temperatures, they have excellent thermal stability, which can meet the valve requirements of high-temperature working conditions such as engine cooling and fuel heating, and prevent sealing failure caused by material thermal deformation.

 

 

Titanium alloy valves also have the advantages of non-magnetism, good seismic resistance and anti-scaling property. Non-magnetism avoids interference with ship navigation and detection equipment. Good seismic resistance reduces the risk of loosening and leakage caused by vibration. The anti-scaling property reduces cleaning and maintenance work and lowers operation and maintenance costs.

 

The smelting and processing technology of titanium alloys is continuously optimized, which improves the yield and reduces the manufacturing cost by 25%. The price of Ti31 flange forgings has dropped by nearly 40% compared with 2015, and the cost gap with traditional materials has been greatly narrowed. Large-scale and high-end ocean-going ships adopting titanium alloy valves can achieve considerable economic returns through long service life, low energy consumption and less maintenance.

 

Ruihang Group mainly produces the raw materials for your precision manufacturing. For more details,please reach us to the email:Sam.Rui@bjrh-titanium.com