Use of titanium alloy plate in power industry

Built in the coastal areas of thermal power plants and nuclear power plants, is the point of sea water as the condenser cooling water. The function of the condenser is tantamount to condense the steam into water. Typically, the condenser is made of copper alloy tube, such as aluminum brass tube, this tube can only be used in a clean sea area to obtain satisfactory results, the problem is the rapid deterioration of seawater, aluminum brass tube will be affected by the seawater containing hydrogen sulfide Severe corrosion, frequent leaks. The advantage of using a titanium condenser lies in its long life and corrosion resistance. The corrosion resistance of titanium alloy plate in the performance of chemical corrosion and corrosion of titanium on both seawater, sulfide. Chloride-induced corrosion as well as pitting corrosion caused by marine organisms and sediments are highly resistant; on the other hand, it is also capable of withstanding accelerated corrosion due to high-speed seawater and local eddy currents due to rapid titanium surface Repairing the damaged protective oxide film, even in the seawater with silt sand and diamond sand at a flow rate of 2 m / s, the erosion rate on the Qin surface is very low. Therefore, the condenser made by milling can improve the flow rate of the sea water, which is favorable for improving the cooling effect.

Due to the high specific strength of titanium alloy plate, good fatigue performance and corrosion resistance, it is equally suitable for steam turbine blades, mainly the last few stages of the low pressure section. Turbine blades are usually made of martensitic chromium stainless steel. The proportion of steel, for high-speed rotating turbine, steel leaves to withstand the huge centrifugal force. In addition, the water vapor is often associated with chloride phase sulfide, which is due to leaks and other causes of the condenser. These media lead to pitting on the surface of the blade, crevice corrosion between the root and the tip of the blade, or the cramp, and the corroded part becomes the source of the crack. Crl3 steel fatigue performance is not ideal, with a saturated solution of sodium chloride corrosion environment, especially in the case of lower pH and dissolved oxygen, Crl3 steel fatigue strength decreased significantly.

The use of titanium blades directly according to the original geometry instead of steel blades, the situation will be considerably improved. Titanium leaves light. At the same speed under the centrifugal force of the root can be reduced by 40%. In addition, corrosion resistance of titanium vane to salt steam is far better than that of steel, the fatigue performance of Qingan Gold is also higher than that of stainless steel. In the air, the fatigue strength of Ti-6Al-4Y alloy is about 30% higher than that of Cr13 steel, while the fatigue strength of Crl3 steel in sodium chloride solution is also reduced by 2 / 3-4 / 5, Titanium alloy fatigue performance is not affected. Therefore, taking into consideration the pros and cons of fatigue performance under corrosive conditions is the most important factor of titanium on behalf of the steel.

Titanium plate can be used as a generator guard ring. the entire turbine generator system, the guard ring is an important component of the large generator guard ring requirements are high strength, good fracture resistance, stress corrosion cracking in aqueous media is not sensitive, and should be non-magnetic. The current grommet is made of an austenitic Fe-Mn-Cr alloy which has a strong tendency of stress corrosion cracking and also has problems of achieving superior strength and reliability. In contrast, the exact strength of titanium alloy plate guard ring is easy to meet the design requirements, and non-magnetic, stress corrosion is not sensitive, so the use of titanium ring is appropriate. At present, the Soviet Union holds the leading position in this respect.