Titanium Valve

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 purest titanium iodide impurity content 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 1725 ° C, thermal conductivity λ = 15.24W / (mK), tensile strength σb = 539MPa, elongation δ = 25%, section Shrinkage ψ = 25%, elastic modulus E = 1.078 × 105MPa, hardness HB195. ◆ The density of titanium alloy is generally about 4.51g / cm3, which is only 60% of steel. The density of pure titanium is close to that of ordinary steel. Some high-strength titanium alloys exceed the strength of many alloy structural steels. Therefore, the specific strength (strength / density) of the titanium alloy is much greater than that of other metal structural materials. See Table 7-1, which can produce parts with high unit strength, good rigidity, and light weight. The aircraft engine components, skeleton, skin, fasteners and landing gear are all made of titanium alloy. ◆ Titanium alloy works in humid atmosphere and seawater medium, and its corrosion resistance is far better than that of stainless steel. It is particularly resistant to pitting, acid, and stress corrosion; organic objects such as alkali, chloride, and chlorine, nitric acid, and sulfuric acid Etc. Have excellent corrosion resistance. However, titanium has poor resistance to reducing oxygen and chromium salt media.