Tungsten — the most refractory metal, it is a little widespread in the nature and does not meet in a free look. Long time this metal did not find the broad application in the industry, only in the second half of the 19th century began to study influence of its additives on properties of steel.

Sulfur represents the 16th chemical element of the periodic table of Mendeleyev with alphabetic reference of "S" and with an atomic mass of 32.059 g/mol. She shows the expressed nonmetallic properties and also is in structure of different ions, forming acids and many salts.

Characteristic property of metal elements – ability to give the electrons which are at the external electronic level. Thus, metals reach a steady state (receiving completely filled previous electronic level). Nonmetal elements, on the contrary, seek not to give the electrons, and to accept strangers to fill the external level to a steady state.

Titanium is chemical element IV of group of periodic Mendeleev's system, it treats light metals. Natural titanium is presented by mix of five stable isotopes, also several artificial is known radioactive.