The application of titanium metal in marine

The application of titanium metal in marine

1. Deep sea submersible

China's Jiaolong manned submersible, with a maximum diving depth of 7000 meters, was built in 2002. Hydrothermal  and biological mining have been completed, successfully creating a new historical record of manned deep diving, breaking through 7000 meters for the first time and reaching a maximum depth of 7020 meters. This means that Jiaolong has collected and deployed a number of deep-sea scientific research projects. On June 24, 2012, Jiaolong became the operational manned submersible with the deepest diving ability in the world in the Mariana Trench test area of the Western Pacific, and can move freely in the vast sea area accounting for 99.8% of the world's ocean area. Table 2 shows the comparison of technical indexes and performance indexes of manned submersible.

Comparison of technical and performance indicators of manned submersibles

2. Development and Utilization of Ocean Energy

In coastal power stations and nuclear power stations, condenser is an important large-scale equipment, and the cooling medium is seawater. It is traditionally made of steel and copper alloy materials, but it has poor seawater corrosion resistance and short service life. In seawater, especially under the action of polluted seawater, copper alloy condenser is prone to pitting corrosion, pitting corrosion, stress corrosion and fatigue corrosion, resulting in equipment leakage, forcing the power station to stop production and causing heavy economic losses. Practice at home and abroad has proved that titanium is the most suitable material for condenser and heat exchanger of power station.

condenser used in Binhai power station has many advantages: it can locally use seawater as cooling medium; Good corrosion resistance and long service life: high heat exchange efficiency and good economic benefits; High safety performance, reduced outage maintenance time, high production efficiency and so on.

In thermal engineering, it is also used in superconducting motor. Titanium has the characteristics of non-magnetic, high specific strength, low temperature resistance and low density. It has the best comprehensive adaptability. It is a very ideal superconducting rotor structural material.

3. Submarine

Titanium alloy has high specific strength, good plasticity and fatigue resistance, seawater corrosion resistance, appropriate formability, weldability and cold and hot workability, which is suitable for submarine shell materials; At the same time, it is non-magnetic and not easy to be attacked by magnetic mines; Titanium alloy has high sound transmission coefficient and is suitable for making sonar deflector.

Russia is an international leader in the research and manufacturing technology of building all-titanium nuclear submarines, and it is also the first country to build pressure-resistant hulls with titanium alloys.

4. Deep sea space station

The deep-sea mobile space station will be mainly used for marine scientific exploration, known as "Tiangong-1" in the ocean. The establishment of the space station is not restricted by the harsh wind and wave environment on the sea surface. It can directly control the operation tools and devices in the deep sea area for long-term and all-weather, and carry out underwater military engineering operation, resource exploration and development. It will form a three-dimensional deep-sea operation system of "one main and two auxiliary" with the surface platform and shuttle multi-functional manned submersible (between the workstation and the mother ship, with the functions of transportation, maintenance, communication and life-saving).

No matter the United States, Russia or China, the construction of its deep-sea space station is inseparable from the support of titanium and titanium alloy key materials. To ensure the safety, reliability and superior performance of the deep-sea space station, a large number of titanium and titanium alloy materials need to be used.

5. Sea water desalination

With the gradual improvement of people's understanding of the corrosion law of distillation desalination unit and the advantages of titanium, the material selection of heat transfer tube in seawater desalination unit has changed significantly. Titanium heat transfer tube with excellent corrosion resistance has begun to be used more and more. Especially in multi effect distillation (MED) unit, titanium is often used in the top three rows of heat transfer tube bundle which are relatively seriously washed by seawater distribution.

For the grade of titanium, the most widely used are industrial pure titanium TA1 (GRL) and TA2 (Gr2). The seawater heater with higher temperature uses ta9 (GR7, Ti PD) and TA10 (Gr12, ti-0.3mo-0.7ni). The two brands have better corrosion resistance. TA1 (GR1) TA2 (Gr2) and other industrial pure titanium have special stress corrosion resistance in seawater, natural water and various chloride solutions.

As mentioned above, titanium has the advantages of light weight, high strength, corrosion resistance, good heat resistance and strong reliability, especially for chlorine. There is no doubt that titanium is one of the most potential materials} for the application of seawater desalination industry. Titanium welded pipe is the most used in seawater desalination equipment, which is mainly used in heaters, condensers, distillers, evaporators, heat exchangers, etc. nickel, aluminized brass and copper nickel alloy pipes have been used before. Due to the obvious advantages of rotten pipe compared with seamless pipe, such as unlimited pipe length, good wall thickness uniformity, high degree of production automation, and using thin-walled titanium welded pipe for periodic corrosion, obvious benefits have been achieved. It can not only save cost, but also improve the heat exchange coefficient. Short titanium welding, high production efficiency and high yield.