. Railway mechanical engineer . r various spans and thicknesses of material, whichindicate that the material has an elastic limit of not less than120,000 lb. per sq. in., providing the material docs not receive apermanent set to exceed .01 in. After the deflection test the])lates should be broken and the angle at vvliich failure occursobserved. This angle should not be less than shown in thetable; the greater the angle the better is the heat treatment. IJe 9/32 .Vie 11/32 13327/1615/32 •A 17/32 9/16 19/32 H Ti:sT ov ,licllcttion Tot. IJcHccIion Breaking Tchi. in Uunrlrcdths Mini
. Railway mechanical engineer . r various spans and thicknesses of material, whichindicate that the material has an elastic limit of not less than120,000 lb. per sq. in., providing the material docs not receive apermanent set to exceed .01 in. After the deflection test the])lates should be broken and the angle at vvliich failure occursobserved. This angle should not be less than shown in thetable; the greater the angle the better is the heat treatment. IJe 9/32 .Vie 11/32 13327/1615/32 •A 17/32 9/16 19/32 H Ti:sT ov ,licllcttion Tot. IJcHccIion Breaking Tchi. in Uunrlrcdths Minimum Angle olBreakage, Degrees, 10493 78 CASE HARDENING C. V. Landrum (Nashville, Chattanooga & St. Louis) : I usethe old method of casehardening—bone meal, old leather, pulver-ized charcoal and a little sprinkling of prussiate of potash. Iuse a drum 12 in. in diameter and from two to four feet long,the length being governed by the amount to be hardened. Iturn a sliglit flange on one end of the drum, stand it on end, cut. Fig. 3—Link Trunion out a piece of J-4 in. or fg in. iron to fit, then drop it in and putabout two inches of fire clay on top of it, pack it well so as tomake it as near air tight as possible, then put in about 2 in. or 3in. of bone meal and old leather, cut up; then a layer of piecesto be hardened is packed in. Space is left at the top for two orthree inches of fire clay, which is held in place by another 54 }i, in. iron plate, a ^ in. bolt passing through holes in the drumto keep it in place. It is then placed in the furnace and kept 1,600or 1,700 deg. F,, as near as I can come to it without a pyrometer. 476 RAILWAY AGE GAZETTE, MECHAXICAI. EDITION 89, No. 9. That temperature maintained for eii;lit hours will penetrate % If the heat is lower the case will be thinner. For quickwork or a roundhouse job I use -}4 lb. of prussiate of potash to 1gal. of pulverized charcoal. This put in a pipe just large enoughto accommodate the pieces to
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