Titanium is silver colored and one of the most corrosion-resistant structural metals. It took 120 years from the first titanium discovery in the late 18th century to the production of pure titanium and then the metallurgist spent nearly 40 years put the pure titanium obtained in the laboratory into the industrial production. Many researchers have done plenty of experiments. In 1948, Dupont company finally successfully produced tonnage porous and irregular shape titanium , that is, sponge titanium.
The production principle of sponge titanium is to reduce TiCl4 by Mg and generate Ti and MgCl and then vacuum distillation to remove the residual Mg and MgCl2 to obtain a pure, spongy, multi-empty titanium lump. The titanium lump is taken out, peeled, cut, and crushed to make sponge titanium.
During the reduction, distillation process, influenced by the complex factors such as temperature, pressure, furnace condition and segregation, there exist some impurities in titanium sponge lump. According to Chinese standard GB/T 2524, titanium sponge can be classified 0-5 levels, a total of six grades, namely the MHT 100, MHT 110, MHT120, MHT140, MHT160, MHT200 (The number refers to Brinell hardness maximum values), purity (%) quality generally is 99.1 ~ 99.7, total impurity elements (%) of 0.3 ~ 0.9, impurity element oxygen quality (%) of 0.06 ~ 0.30, hardness (HB) is 100 ~ 200.