. Proceedings of the annual convention . of length of slotand wheel load were tried. These tests are listed in Table 2. It was found that with alonger slot the rail base would bend, and this was overcome by welding stiffncrs to thetop of the rail The fractures produced in these tests are shown in Figs. 3 and results have been obtained with a combination of 50,000-lb wheel load and a slot6 in. in length. As would be expected, the combination of flow of the metal by heavywheel loads to produce shelling cracks and high bending stresses to produce detailfractures results in a wide sc
. Proceedings of the annual convention . of length of slotand wheel load were tried. These tests are listed in Table 2. It was found that with alonger slot the rail base would bend, and this was overcome by welding stiffncrs to thetop of the rail The fractures produced in these tests are shown in Figs. 3 and results have been obtained with a combination of 50,000-lb wheel load and a slot6 in. in length. As would be expected, the combination of flow of the metal by heavywheel loads to produce shelling cracks and high bending stresses to produce detailfractures results in a wide scatter in the type of failure produced. Stress Relief of Specimen During Rolling-Load Tests Stress relaxation tests were made at Battelle Memorial Institute by Messrs. D. and H. J. Grover. These tests were made by cutting strips from a 152 lb railroadrail and producing a given stress by bending the strips in clamps, and the stress wasrelieved by annealing the clamped strips. These tests showed that the stress produced 1246 Rail. U-i2B ^VBHur U-34-B Fig. 2—Weir Kilby Corp. flame-hardened rails before and after testing. Top row—Before testing. Etched with amonium persulfate which darkensflame-hardened area. Lower two rows—After testing. Etched in hot SO percent hydrochloric acid. Average Cycles in Specimen Brinell Rolling No. Type of Specimen Hardness Machine U12A 132-lb rail, flame hardened 345 1,008,CX)0 U12B 132-lb raO, flame hardened 345 875,000 U34A 132-lb rail, flame hardened 364 930,000 U34B 132-lb rail, flame hardened 364 767,000 in the bent strips was relieved by stress-relief heat treatments. The final recommenda-tion based on these tests was that the stress in rail steel was best relieved by annealingthe steel at 1000 deg F. Based on these tests the Shelly Rail Joint Contact Committeedecided that stress relief tests should be made on full section rails after they had beenrolled in laboratory rolling machines for various portions of their expected life be
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