There are two isomeric titanium crystals: Below 882 ℃ for close-packed hexagonal structure α
titanium, more than 882 ℃ for β titanium body-centered cubic. Alloying elements according to their
effect on the phase transition temperature can be divided into three categories: ① stable α-phase,
improving the phase transition temperature of the elements of α stabilizing element, aluminum,
carbon, oxygen and nitrogen.
Titanium bars Which aluminum is the main alloying elements titanium, improving its normal temperature and high temperature strength of the alloy, reduce the proportion increased
elastic modulus have a significant effect. ② stable β-phase, reducing the element of the phase
transition temperature of β stabilizing element, and can be divided isomorphous and eutectoid type
two kinds. Application of titanium alloy products, the former molybdenum, niobium, and vanadium;
latter chromium, manganese, copper, iron, and silicon. ③ small element of the phase transition
temperature of the neutral elements, zirconium, tin and so on. Oxygen, nitrogen, carbon and hydrogen
are the main impurities of titanium. Oxygen and nitrogen in the α phase has a greater solubility of
the titanium alloy has a significant strengthening effect, but the plastic down. Usually provides
the oxygen and nitrogen content of titanium in the 0.15 to 0.2% and 0.04% to 0.05% or less,
respectively. The solubility of hydrogen in the α phase is very small, titanium dissolved in excess
hydride hydrogen will produce the alloy brittle. Titanium is usually controlled hydrogen content of
0.015% or less. The hydrogen dissolved in the titanium is reversible, can be removed by vacuum
annealing. Density copper titanium is generally about 4.5g / cm3, only 60% of steel, titanium's
strength was close to the strength of ordinary steel, some high-strength titanium alloy structural
strength than a lot of steel. Therefore, titanium strength (strength / density) is much larger than
other metal structural materials. Copper titanium alloy with high strength and low density, good
mechanical properties,
titanium grade 2 sheet good toughness and corrosion resistance. In addition, the process performance titanium poor machining difficulties in thermal processing, it is very easy to absorb nitrogen
hydroxide carbon and other impurities. There are poor abrasion resistance, complex production
process. Titanium is mainly used for the production of aircraft engine compressor components,
followed by the structure rockets, missiles and high-speed aircraft. Light quality titanium and
titanium alloys, high-strength, yield ratio, non-magnetic, there is biologically inert and has
excellent corrosion resistance. In marine environments, titanium and titanium alloys almost no
corrosion, has excellent corrosion resistance in most chemical media. Now, with the advancement of
technology and the application of new materials industries for increasing the degree of titanium
valves as a variety of special circumstances and special fluid media delivery system essential
products have been widely applied. However, different fields and industries fluid medium and
environmental conditions vary, the titanium material of the valve performance and other requirements
are different. Meanwhile, due to the requirements of the different components of performance
titanium valves differences, different molding process as well as reduce the cost of some parts need
to use alternative materials and other factors, selection as one of technical problems must be the