Titanium is an element with an atomic number of 22 in the periodic table, and a secondary group element in the fourth cycle, namely the IVB group. In addition to titanium, this group of elements also includes zirconium and hafnium. Their common feature is high melting point, which forms a stable oxide film on its surface at room temperature.

Wuxi Changrun has exported Titanium-steel clad tube sheets, Titanium plates and Titanium bars  to foreign customers. 

The Ten Characteristics of Titanium 

1.Low density, high strength, and high specific strength

The density of titanium is 4.51g/cm3, which is 57% of steel. Titanium is less than twice as heavy as aluminum and three times stronger than aluminum. The specific strength (strength/density ratio) of titanium alloy is the largest among commonly used industrial alloys (see table 1). The specific strength of titanium alloy is 3.5 times that of stainless steel, 1.3 times that of aluminum alloy, and 1.7 times that of magnesium alloy, making it an essential structural material in the aerospace industry.

 Table 1. Comparison of density and specific strength between titanium and other metals

2.Excellent corrosion resistance

The passivity of titanium depends on the presence of an oxide film, and its corrosion resistance in oxidizing media is much better than in reducing media. High rate corrosion occurs in reducing media. Titanium is not corroded in some corrosive media, such as seawater, wet chlorine gas, chlorite and hypochlorite solutions, nitric acid, chromic acid, metal chlorides, sulfides, and organic acids. But if a small amount of oxidant is added to the acid, a passivation film will form on the surface of titanium. So in a mixture of strong sulfuric acid nitric acid or hydrochloric acid nitric acid, and even in hydrochloric acid containing free chlorine, titanium is corrosion-resistant. The protective oxide film of titanium is often formed when the metal contact with water, even in small amounts of water or steam. If titanium is exposed to a strong oxidizing environment completely devoid of water, it will undergo rapid oxidation and produce violent reactions, often even leading to spontaneous combustion. This phenomenon has occurred in the reaction between titanium and fuming nitric acid containing excess nitrogen oxide, as well as between titanium and dry chlorine gas. So to prevent such reactions from occurring, water must be involved.

3.Good heat resistance performance

Normally, aluminum loses its original properties at 150 ℃, stainless steel loses its original properties at 310 ℃, while titanium alloy still maintains good mechanical properties at around 500 ℃. When the aircraft speed reaches 2.7 times the speed of sound, the surface temperature of the aircraft structure reaches 230 ℃, and aluminum and magnesium alloys can no longer be used, while titanium alloys can meet the requirements. Titanium has good heat resistance and is used for the discs and blades of aircraft engine compressors, as well as the skin of aircraft rear fuselage.

4.Good low-temperature performance

The strength of certain titanium alloys (such as Ti-5AI-2.5SnELI) increases with the decrease of temperature, but the plasticity does not decrease much. They still have good ductility and toughness at low temperatures and are suitable for use at ultra-low temperatures. It can be used on dry liquid hydrogen liquid oxygen rocket engines or as ultra-low temperature containers and storage tanks on manned spacecraft.

5.Non-magnetic

Titanium is non-magnetic and will not cause mines to explode when used in submarine shells.

6.Low thermal conductivity

The comparison of thermal conductivity between titanium and other metals is shown in Table 2. Titanium has a low thermal conductivity, only 1/5 of steel, 1/13 of aluminum, and 1/25 of copper. Poor thermal conductivity is a disadvantage of titanium, but in certain situations, this characteristic of titanium can become a special advantage for use.

 Table 2. Comparison of HEAT CONDUCTANCE between titanium and other metals

7.Low elastic modulus

The comparison of elastic modulus between titanium and other metals is shown in Table 3. The elastic modulus of titanium is only 55% of steel, which is a disadvantage when used as a structural material.

Table 3. Comparison of ELASTIC MODULUS between titanium and other metals

8.The tensile strength is very close to the yield strength

The tensile strength of Ti-6AI-4V titanium alloy is 960MPa, the yield strength is 892MPa, and the difference between the two is only 58MPa, as shown in Table 4.

Table 4. Comparison of tensile strength and yield strength between titanium and other metals

9. Titanium is easily oxidized at high temperatures

Titanium has a strong binding force with hydrogen and oxygen, so attention should be paid to preventing oxidation and hydrogen absorption when using it. Titanium welding should be carried out under argon protection to prevent contamination. Titanium tubes and thin plates need to be heat treated under vacuum, and the heat treatment of titanium forgings should control the micro oxidizing atmosphere.

10. Low anti damping performance

Using titanium and other metal materials (copper, steel) to make clocks of exactly the same shape and size, striking each clock with the same force will reveal that clocks made of titanium oscillate for a long time, meaning that the energy given to the clock by striking is not easily dissipated. Therefore, we say that titanium has low damping performance.

Three Special Functions of Titanium

1.Shape memory function

It refers to the ability of Ti-50% Ni (atomic) alloy to restore its original shape under specific temperature conditions, and is called shape memory alloy.

2.Superconductive function

It refers to Nb-Ti alloy. When the temperature drops to near absolute zero, the wire made of Nb-Ti alloy loses its resistance. Any large current passing through the wire will not generate heat and there is no energy consumption. Nb-Ti is called a superconducting material.

3.Hydrogen storage function

It refers to Ti-50% Fe (atomic) alloy, which has the ability to absorb a large amount of hydrogen gas. By utilizing this feature of Ti Fe, hydrogen can be safely stored, meaning that hydrogen storage does not necessarily require the use of high-pressure steel cylinders. Under certain conditions, Ti Fe can also release hydrogen, which is known as an energy storage material.