. Railway mechanical engineer . Per CentCarbon Steel The several grades of specimens were heated simultan-eously in an electric muffle furnace for one hour each atdifferent temperatures ranging from 900 to 1,700 deg. gases in the furnace at all times corresponded in analysisto the atmosphere of the room, which was: oxygen, 20 percent; carbon dioxide, per cent; carbon monoxide, nil;nitrogen, per cent by difference. On removal from the furnace, the spiecimens were rapidl)quenched in oil, the quantity of scale was then determined. Method of Determining Scale In determining th
. Railway mechanical engineer . Per CentCarbon Steel The several grades of specimens were heated simultan-eously in an electric muffle furnace for one hour each atdifferent temperatures ranging from 900 to 1,700 deg. gases in the furnace at all times corresponded in analysisto the atmosphere of the room, which was: oxygen, 20 percent; carbon dioxide, per cent; carbon monoxide, nil;nitrogen, per cent by difference. On removal from the furnace, the spiecimens were rapidl)quenched in oil, the quantity of scale was then determined. Method of Determining Scale In determining the weight and thickness of the scale, it i^mandatory to effect a complete removal of the oxidized layer:>without removing any metallic iron. Experiments were madewith several chemical methods, each of which was subject tothe same criticisms—excessive removal of metallic iron orfailure to completely remove the oxides. A method was suggested of heating in cyanide for 10minutes at 1,450 deg. F., followed by water quenching and. OOi \ 900 1000 noo fZOO 1300 1400 ISOO KOO Degrees Fohr. Fig. 2—Extent of Scaling on a Per Cent Carbon Steel cleansing in soda solution. This procedure was found to beconspicuously successful. The scale was completely removedby this unique application of cyaniding and specially pre-pared specimens cyanided in this manner, showed variationsof dimension and weight so small as to have no effect uponthe final results. Fig. 1 is a graphical presentation of the extent of scalingon a per cent carbon steel. Attention is called tothe fact that below 1,200 deg. F. the amount of scale formedin one hour is practically negligible. Above this temj>erature,however, the curve rises rapidly and at 1,600 deg. F. thespecimens scaled on Uie average grams per sq. in. ofsurface exjxsed, and lost approximately in. in eachdimension. Fig. 2 portrays the amount of scaling on a percent carbon steel. As in the case of the low carbon ma
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
