. Transactions. Fig. 66.—Fays A, formed by stamping letters at ax angle into a pressureplug; after firing 200 rounds, polished and etched. X 50. 304 NITROGEN IN STEEL AND THE EROSION OF GUNS The Cannon Section of tlio Engineering Division of Ordnance becameinterested in this work and authorized the manufacture of a hner for a75-mm. gun out of chrome-vanadium steel. This seems an unfortunateselection, because a liner for a 75-mm. gun will fail for other reasons in acertain number of cases as shown above. The unpublished reports ofthe Cannon Section show that a test made in 1914 on machine-gunba
. Transactions. Fig. 66.—Fays A, formed by stamping letters at ax angle into a pressureplug; after firing 200 rounds, polished and etched. X 50. 304 NITROGEN IN STEEL AND THE EROSION OF GUNS The Cannon Section of tlio Engineering Division of Ordnance becameinterested in this work and authorized the manufacture of a hner for a75-mm. gun out of chrome-vanadium steel. This seems an unfortunateselection, because a liner for a 75-mm. gun will fail for other reasons in acertain number of cases as shown above. The unpublished reports ofthe Cannon Section show that a test made in 1914 on machine-gunbarrels of all usual gun steels and some unusual steels showed chrome-vanadium steel to rank first. In the case of a machine gun, the whitelayer is present bat of not much importance, so that a chrome-vanadiumsteel gun of some large caliber might be expected to do very Fig. —Letter V stamped at angle into small piece op steel treated inNHs at 650° C. FOR 4 hr.; polished and etched 10 sec. with 4 per cent, nitricACID. X 50. Fig. 56 is a reproduction of one of Professor Fays photographs;this was produced by actual firing. The results shown in Fig. 57 wereformed in the ammonia furnace. The similarit} is not perfect, ofcourse, the high pressure in one case making the effect slightly shows, however, that the action is selectively faster on the portionsthat have suffered plastic deformation. Fig. 58 is the thread of a tensionbar split in two before treating; only the side that took the pull is affected,if the expermient is discontinued in time; also, only the outside of thecontracted portion of the bar is affected. In looking for steels that resist this penetration, it would seem evidentthat thoy must l)e of such composition as to resist the formation of the H. E. WHEELER 305
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
