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Full text of "Metallurgy Of Cast Iron"

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PROPERTIES   OF   ORES   USED   IN   MAKING   CAST   IRON.     2?                      ]
Manganese Is  found  in  nearly all  iron  ores.    It                |
readily alloys with iron,  and all the manganese con-                 \
tained in pig iron is obtained from the ores.    Manga-                'J 
nese occurs in ores in the form of manganese dioxide
and  manganese  oxide.     Some  ores  are   so   high   in                4
manganese tnat they are called manganiferous ores,
and of late years their reduction has been achieved in                ,\
blast furnaces about as readily as iron ore is reduced,
although  at  one  time  it  was thought impossible to                 ,,
obtain high manganese pig from a blast furnace.                          j<
Ferro=manganese is obtained by smelting manganiferous ores in a blast furnace, and is placed on the market as a commercial product containing from 40
per cent to 90 per cent of manganese.    The standard               j;
contains from 79 to 81 per cent.    _                                              j   .
Spiegeleisen or " Spiegel" is a product of manganif-                I
erous ores, but lower in manganese than ferro-manga-                !
nese.    It ranges  from  7  per cent to 40 per cent of               \t
metallic manganese.    The standard contains from 19                (J
to 21 per cent.    In this form it generally presents a                ', '
silvery white fracture with a crystalline structure.    By               ., * -
some this metal is   called "looking-glass iron," the               /^
English translation of Spiegeleisen.     Spiegeleisen is              '*$',
readily produced, whenever   sufficient  manganese  is               \f^
present in the ore.    Both these manganese metals are               jf|V
chiefly used in the manufacture of steel in its many                 v|r
and various grades.                                                                              if j
Phosphorus exists in most iron ores.   Almost all the                l| <*
<> r tt
phosphorus   contained  in  the  ore,   fuel  and  flux  is               ^fj
reduced   and   absorbed   by the  metallic  iron  when               [ I)
smelting or remelting it.    Low phosphorus ores are                ?;
generally of greater value than high phosphorus ores.               f|f;
For Bessemer iron,   in which  phosphorus  must not               |v>