The Development of Titanium abroad
In 1940, Luxembourg scientist W.J. Kroll used titanium to reduce TiCl4 to produce pure titanium. Since then, the magnesium reduction method (also known as the Clauer method) and the sodium reduction method (also known as the Hunter method) have become industrial methods for producing titanium sponge. In the United States, 2 tons of titanium sponge was produced by magnesium reduction in 1948. And since then, the industrial production of titanium began.
In 1947, people began to smelt titanium in the factory. In that year, the output was only 2 tons. Production in 1955 surged to 20,000 tons. In 1972, the annual output reached 200,000 tons. Titanium has a higher yield strength than steel, and its weight is almost half that of the same volume of steel. Titanium, although slightly heavier than aluminum, has a yield strength twice that of aluminum. The specific strength of titanium is higher than that of aluminum and steel, and the specific modulus is very close to that of aluminum and steel. In space rockets and missiles, titanium is used in large quantities instead of steel. According to statistics, the amount of titanium used for space navigation in the world has reached more than 1,000 tons per year. Very fine titanium powder is also a good fuel for rockets, so titanium is known as cosmic metal and space metal.
Titanium reacts easily with air at high temperatures, but has a melting point of up to 1668 °C. At normal temperature, titanium is not afraid of aqua regia and dilute nitric acid corrosion, but it is not resistant to sulfuric acid of 5% or more and 7% hydrochloric acid. Titanium is not afraid of sea water at normal temperature. Some people once sank a piece of titanium to the bottom of the sea. After five years, they took it up and saw that there were many small animals and sea plants on the top, but there was no rust at all, and it was still shining.
People began to use titanium to make submarines - titanium submarines. Because the titanium is very strong and can withstand high pressures, the submarine can sail in deep seas as deep as 4,500 meters.