The oxidation reactions are exothermic and therefore the iron remains melted. With this method the almost complete elimination of the carbon is then carried out which is then reintroduced in a controlled quantity. To eliminate phosphorus, the oxide of which is not sufficiently volatile, the converter is coated with basic refractory bricks that discourage phosphorus such as phosphate (Thomas slag) as shown in Machining Lathe Perth.
This goes into a Bessemer converter into which it is blown air that carries out the oxidation of carbon, silicon and phosphorus. Manganese is also added which, by oxidizing, discourages silica in the form of fuse manganese silicate.
Other processes use reverb furnaces (Martin ovens) and electric furnaces: the latter are used to produce special steels. The steel contains between 0.2 and 1.5% of carbon. Low carbon content steels (soft steels) are ductile and malleable, medium ones (between 0.2 and 0.6% carbon) can be forged and welded and are used for structural elements. Those with high carbon content are particularly hard and are used to build tools as part of Machining Lathe Perth.
Stainless steels contain chromium and nickel (remember the so-called 18-10 steel containing 18% chromium and 10% nickel), those for tools that contain tungsten, vanadium and chromium. The mechanical properties of a steel do not depend only on its chemical composition, but also on the heat treatments it has undergone.
The steel becomes very hard and fragile if it is heated near the melting point and rapidly cooled by immersion in water or oil (tempera), the fragility is reduced by the annealing process at a temperature of around 300 ° C. these changes of properties are linked to the iron-carbon phase equilibria and to the stabilization by rapid cooling of the stable phase at high temperature (austenite).
Pure iron exists in three crystalline modifications: at low temperature the α form is stable with a cubic body-centered lattice; at 910 ° C there is the γ shape with a face-centered cubic structure; at 1390 ° C a cubic shape with a centered body returns to be stable, the form; iron melts at 1535 ° C. up to 768 ° C it is ferromagnetic or it retains the magnetization even when the action of the magnetizing field has ceased.
Pure metal is silvery, ductile and malleable and combines with almost all non-metals at moderate temperatures. It dissolves in non-oxidizing acids giving the Fe2 + ion, while in the oxidizing ones it gives the Fe3 + ion; in a strongly oxidizing environment it is passive. The main states of iron oxidation are II and III. Iron is an extremely important biological element: it is present in hemoglobin and myoglobin as well as in various enzymes.