. Official proceedings . stage in the manu-facture. In other words, **a stitch in time saves nine. We used a system of microscopic examination of cartridgecases between various shop operations. For instance, we made a microscopic examination immedi-ately after a certain draw and again after the case had beenannealed to check on the heat treatment. A different heat treat-ment was found to be necessary after various operations because•of the varying thickness of the metal. The structure of themetal at the open and closed ends of the cartridge case wasdifterent because of variation in thickness a
. Official proceedings . stage in the manu-facture. In other words, **a stitch in time saves nine. We used a system of microscopic examination of cartridgecases between various shop operations. For instance, we made a microscopic examination immedi-ately after a certain draw and again after the case had beenannealed to check on the heat treatment. A different heat treat-ment was found to be necessary after various operations because•of the varying thickness of the metal. The structure of themetal at the open and closed ends of the cartridge case wasdifterent because of variation in thickness and variation inamount of drawing or working the metal had undergone. Themetal could not be too hard in the finisUed case else it mightcrack while the shell was fired from the gun. It could not betoo soft, for it then would bulge and stick in the gun. It isrequired that these cases be used eight (ir ten times in the gunbefore finally being scrapped, which places great im])ortance onthe physical and chemical FtO. (). PVROMKTKR Ill the iiiamitacturc ol llic steel slirapnel shell we instituteda nielhud of heat treatment which, in my knowledge, is quitenovel and unicjue. The novel features consisted largely in theconstruct it ni of the heating furnace. * This furnace contained six tubes in a horizontal plane, eachhaving a capacity of 19 shells. Depending upon the amount ofcarhdii cdiitained in the particular lot of shells the furnace tem-perature was maintaiiud within 10 degrees of some pointbetween 1550 degrees and lOoD degrees and the shellspermitted to remain for about fifty minutes. The furnace temperature was constantly under careful andaccurate control, being checked by a number of pyrometer con-nections to various parts of the furnace. (Fio. 9)
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Keywords: ., bookauthorrailwayc, bookcentury1900, bookdecade1900, bookyear1901
