Which Is More Corrosion-resistant, Pure Titanium Or Titanium Alloy?

Titanium alloy works in humid atmosphere and seawater medium, and its corrosion resistance is much better than stainless steel; it is particularly resistant to pitting corrosion, acid corrosion, and stress corrosion; it is resistant to alkali, chloride, chlorine-based organic substances, nitric acid, and sulfuric acid. etc. have excellent corrosion resistance. However, titanium has poor corrosion resistance to media with reducing oxygen and chromium salts.
The density of titanium alloys is generally around 4.51g/cm3, which is only 60% of steel. The strength of pure titanium is only close to the strength of ordinary steel. Some high-strength titanium alloys exceed the strength of many alloy structural steels. Therefore, the specific strength (strength/density) of titanium alloys is much greater than that of other metal structural materials.
Titanium is a new type of metal. The performance of titanium is related to the content of impurities such as carbon, nitrogen, hydrogen, and oxygen. The impurity content of relatively pure titanium iodide does not exceed 0.1%, but its strength is low and its plasticity is high. The properties of 99.5% industrial pure titanium are: density ρ=4.5g/cm3, melting point 172. Silicon-titanium alloy wear-resistant floor 5℃, thermal conductivity λ=15.24W/(m.K), tensile strength σb=539MPa, elongation δ=25%, area reduction ψ=25%, elastic modulus E=1.078 ×105MPa, hardness HB195.
Certain environments require the use of special titanium alloys:
1. In a crevice corrosion environment: Pure titanium and titanium alloys are used for general structural parts. In places with physical gaps such as flange surfaces and tube plate surfaces, titanium alloys that are resistant to crevice corrosion must be used, such as: Ti-pd alloy , TI-Mo-Ni alloy.
2. In environments with corrosion and fatigue loads, such as rotating parts, high-strength titanium alloys, such as Ti-6Al-4V, should be used.
3. In situations where the temperature is high, the pressure is high, and it is corrosive, if ordinary pure titanium is used, the thickness of pure titanium will be very thick due to the relatively low allowable stress. Titanium alloys should be used and the amount of material should be reduced to save money. cost.