Electrochemical and metallurgical industry . tions, viz.: 25 to 30, 50 to 55, and70 to 75 per cent silicon content, only these grades of thealloy are shown and described herein. The physical structure of these grades of ferro-silicon isvery interesting. As the percentage of silicon increases from30 to 50 the brittleness of the alloy increases rapidly, and the50 per cent alloy can be crushed between the fingers to octa-hedra about yi a millimeter on an edge. After 50 per cent ispassed the ease of fracture remains practically the same in thevertical plane, but becomes more and more difficult in
Electrochemical and metallurgical industry . tions, viz.: 25 to 30, 50 to 55, and70 to 75 per cent silicon content, only these grades of thealloy are shown and described herein. The physical structure of these grades of ferro-silicon isvery interesting. As the percentage of silicon increases from30 to 50 the brittleness of the alloy increases rapidly, and the50 per cent alloy can be crushed between the fingers to octa-hedra about yi a millimeter on an edge. After 50 per cent ispassed the ease of fracture remains practically the same in thevertical plane, but becomes more and more difficult in thehorizontal plane. After 75 per cent is passed the fracture be-comes more difficult in both planes until the peculiarities notedwith 92 to per cent silicon are attained. In the fracture of ferro-silicon containing 60 per cent ofsilicon, plates were obtained measuring 2 centimeters alongtheir vertical axis, with a width of i centimeter and a thicknessof from I to 2 millimeters. The etching of the ferro-silicon sections was done by im-. FIG. 21.—CARBONLESS IRON V X nS. * A paper read before the American Electrochemical Society, Bostonmeeting. mersing the sample in dilute mixed hydrofluoric and nitricacids for 10 seconds; washing and drying and then immersingin concentrated aqua regia until details were brought outclearly. As a basis of comparison. Fig. 21 shows a practically carbon-less area of Swedish iron magnified 118 diameters, with verticalillumination. Fig. 22 shows 50 per cent ferro-silicon magnified 8 diameters,but does not give the detail presented by this section to theunaided eye, as it then showed distinct laminations running atvarious angles in different grains. Fig. 23 is 52 per cent ferro-silicon, 8 diameters, and shows the large grainformation char-acteristic of sili-c o n. Thesegrains, like thoseof silicon, areplainly visible tothe unaided incipientfractures canalso be seen. Fig. 24 showsferro-silicon hav-ing 75 per centsilicon content, 8diameter
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Keywords: ., bookcentury1900, bookdecade1900, booksubje, booksubjectmetallurgy
