Lexicon
F
Ferrite
Metallographical description of the solid solution (iron-carbon diagram) where carbon is dissolved interstitial in its lattice. Its maximum carbon absorption is only 0.02%. Ferrite is only in low eutectoid steels, can be combined to form an alloy (alloyed steel) and has a high magnetic permeability up to 769°C. Pure ferrite materials possess less firmness, but high ductility. By forming alloys with Si or Cr it gains a special property (electrical sheets). Next to massive and grain boundary ferrite, with carbon contents of between 0.2 and 0.4% as a result of quick cooling from high temperatures, it can form square loop ferrite (Widmannstätten’scher Ferrite). This brittle structure appears mainly in cast materials and after welding.
Ferrite Steels
Steels which on solidification contain a ferrite structure which heat cannot change. This property depends upon ferrite formations. These steels are heat resistant, possess especially strong magnetic fields, do not allow quenching and tend to be coarse.
Ferro-Alloys
Intermediate products produced in coke furnaces, electric arc furnaces or low furnaces, used as additives in iron and steel productions, and contain one or more of the following alloy elements: more than 8% Si = Ferro silicon metal), more than 30% Mn (= Ferro manganese), more than 20 % Cr (= Ferro chrome), more than 40% W (=Ferro tungsten), more than a total of 10% of other alloys e.g. Cu, Al, Ti, V, Mo, Nb, F, are standardised according to European standards and DIN 17560-17599, SEW 1740.
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