Titanium materials are mainly divided into the following categories:
1.Industrial Pure Titanium (pure titanium, CP titanium)
In Japan, it is a general-purpose type of material, commonly known as pure titanium. It contains a small amount of 0, N, C, Fe, H impurities. Because it is high-purity titanium, it is called commercially Pure Titanium. The strength of pure titanium mainly depends on the amount of 0 and Fe. In the JIS standard, it is divided into 4 types according to the content of 0 and Fe. The American ASTM standard also has 4 types of pure titanium for standardization. When corrosion resistance and workability are required, a softer material such as JIS1 should be selected, and when high strength and high strength are required, a soft high-strength material with high Fe content should be selected. In Japan, the most common pure titanium is JIS, two materials with excellent strength and workability, which are used in a wide range. The actual tensile strength of this material is about 380 MPa, which is comparable to the strength of mild steel.
2. Corrosion-resistant Titanium Alloy
Corrosion-resistant titanium alloys refer to corrosion-resistant titanium alloys produced by adding trace amounts of effective elements.
The corrosion resistance of titanium materials is due to the formation of a stable oxide film on the surface. It has superior corrosion resistance equal to or higher than platinum in an oxidizing acid (nitric acid, etc.) when provides oxygen and a chloride ion-containing environment. It is the same as pure titanium in terms of strength, controlled by 0 and Fe, and its workability and weldability are the same as those of pure titanium. Most of the corrosion-resistant titanium alloys are developed by Japanese processing plants. Japan is based on pure titanium, reflecting the main demand for corrosion-resistant materials. Most of the developed corrosion-resistant titanium alloys are in JIS and ASTM standards and are publicly recognized as general-purpose materials.
3. Titanium Alloys with improved strength and workability
This type of titanium alloy refers to a titanium alloy formed by adding alloying elements to improve strength and workability.
Titanium alloys are divided into:
(1) Alpha alloys: As one of the mainstream development of titanium alloys in Europe and the United States, alpha alloys have been developed in large quantities as aircraft engine materials that require cushion resistance. Recently, in Japan, as muffler materials for automobiles and motorcycles, high temperature characteristics are emphasized. Alpha alloys, standardization work is being carried out at the same time as development.
(2) β alloy: A variety of alloy series have been designed in Japan, which have been put into practical use as ball head materials on golf clubs. In addition, in order to improve the corrosion resistance, β alloys contain more than 10%, and a series containing a large amount of alloy components is expected to be a corrosion-resistant alloy in a non-oxidizing environment.
(3) α-β alloy: α-β alloy is an alloy formed by a good combination of the above-mentioned characteristics of α alloy and β alloy, and a representative example is Ti-6Al-4V alloy.
4. High-purity Titanium
High-purity titanium is a sputtering material for forming thin films, and its output is increasing. The grades of 4N (99.99%), 4N5 (99.995%), 5N and 6N are general. The raw material is CP titanium, and the sponge titanium produced by the same process must be strictly controlled and managed in the selection of raw materials to ensure the production of high-quality finished products.
5. Functional Titanium Alloy
On titanium alloys, the additional special functions are very practical alloys. To classify functional titanium alloys, the representative alloys are:
①NbTi series superconducting alloys with excellent basic superconducting properties at the temperature of liquid helium (He).
② NiTi series shape memory alloys that can restore the original shape by heating above the transformation temperature after deformation.
③TiAl intermetallic compounds.
④Superelastic alloys with a huge elastic deformation function, this kind of dream alloys, are being applied in the fields of consumer goods such as springs for automobile parts and frames for glasses.