. Railway mechanical engineer . ILWAY MECHANICAL ENGINEER Vol. 93, No. 12 bonate. The following table and the accompanying curvesexhibit the results: Effects of Temperature on Deith and Rate of PenetrationJCumber Penetrations in inches corresponding lo temperatures m{ houi s in cdse- pciiod About About 1382°- 1742°- Above 1293 F. 1436° F. 1652° F. 1832° F. 1832° F. .046 .064 .114 .148 .160 .060 .090 .146 .204 .232 .076 .112 .180 .236 .292 .08S .126 .212 ,280 .338 . .102 .144 .236 .312 . .112 .158 .270 .348 . .120 .180 .298 . .132 .198 .324 . .
. Railway mechanical engineer . ILWAY MECHANICAL ENGINEER Vol. 93, No. 12 bonate. The following table and the accompanying curvesexhibit the results: Effects of Temperature on Deith and Rate of PenetrationJCumber Penetrations in inches corresponding lo temperatures m{ houi s in cdse- pciiod About About 1382°- 1742°- Above 1293 F. 1436° F. 1652° F. 1832° F. 1832° F. .046 .064 .114 .148 .160 .060 .090 .146 .204 .232 .076 .112 .180 .236 .292 .08S .126 .212 ,280 .338 . .102 .144 .236 .312 . .112 .158 .270 .348 . .120 .180 .298 . .132 .198 .324 . . .218 .350 12 24 36 48 60 72 84 96i08120 Referring to the curves, it will be seen at once that they donot cross one another. Each is altogether above the onesbelonging to lower temperatures. This means that when the temperature of casehardeningis raised, the effect is to get a greater depth of penetration■whatever the length of the period. This is a good generalrule to remember. Again, splendid results, comparatively,. Chart Show Relation of Time and Temperature to Depth ofImpregnation may be gotten with the temperature 1,562-1,652 deg. Forgeneral work, then, this is a good casehardening the temperature quickens results, but except inspecial cases, hardly enough to warrant the practice. Goodresults are obtainable at temperatures below 1,562°-1,652°,so that, if there is need to use them, one may still expectresults in a reasonable time. Note especially that the curves are substantially straightlines. This means that the depth of penetration, at anygiven temperature of casehardening, is practically propor-tional to the length of the period. The simplicity of thisrule gives it great practical value. If penetration to doublethe depth is wanted, then double the time will be required;if three times the depth, then three times the period, andso on. DISTRIBUTION OF CARBON is of service to know the distribution of the carbon in It the casehardened shell. Na
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