PHYSICAL TEST RESULTS OF OXY-ACETYLENE PRESSURE BUTT WELDS OF HEAT TREATED RAILS

In order to develop all pertinent data in regards to continuous welded rail rolling load, flexure, drop and slow bend tests were performed on oxy-acetylene pressure butt welded fully heat treated rails at the request of the Norfolk and Western Railway Company. The fully heat treated rails, 132 lb. RE section, were supplied by the Bethlehem Steel Corporation and the welds were made by the Norfolk and Western Railway Company at their Roadway Material Yard in Roanoke. Eight of these welds were made by the oxy-acetylene pressure butt welding process. They were also normalized. Each of the tests were 6 ft. long with the weld in the center. The rolling load, flexure and drop tests were made at the AAR Technical Center and the slow bend tests were made at the University of Illinois by Professor R.E. Cramer. Two of the weld specimens were subjected to the rolling load test in a 12 in. stroke rolling load machine using a wheel load of 60,000 lb. with the weld placed 2 in. from the support on the cantilever end of rail. Since the wheel path is 10 in. beyond the weld, the weld was subjected to a bending moment of 600,000 in. lb. Under this test procedure, 2,000,000 load applications or cycles without failure is considered a run out. Both of the test specimens ran out at 2,000,000 cycles without failure. The flexure test was performed on a multi-press using a 60,000 lb. repeated load applied on the center of the weld on the rail head with a wheel shaped contact. The rail was supported on its base to have a 48 in. span. Thus, for each cycle of loading the bending moment at the weld varied from 0 to 720,000 in. lb. with the base in tension, giving a calculated maximum stress at the extreme fiber of 26,000 psi tension. Two of the test specimens were subjected to 2,000,000 flexures each without a failure. The two flexure test specimens, as well as two other test specimens, were then subjected to the drop test on a standard rail drop test machine. A 2,000 lb. tup was dropped 22 ft. on the center of weld with the rail head up. The rail was supported on a 48 in. span. As shown on Table 2, the two flexure test specimens failed at the first blow. One test specimen broke through the weld and a welding defect from a pop out on the outer edge of the base was noted. The other flexure test specimen failed 6 in. away from the weld and a transverse progressive defect in the head originating from a grinding crack was noted. One of the two regular test specimens failed outside the weld area after two blows. The other test specimen failed at the first blow through the weld. It was noted that the lower part of the web and the base were partially fused. The slow bend test results were obtained at the University of Illinois by Professor Cramer. The tests were made with the head up on supports 48 in. apart. The load was applied at two points 6 in. on each side of the weld. Thus, the applied bending moment between these load points was nine times the applied load in in. lb. One of the tests failed prematurely through weld. It was noted that the lower web and the base were partially fused. The other test performed excellently and broke 5 in. from the weld at the edge of the beat affected zone. The data obtained under the testing procedure indicates that even though the benefit from the heat treatment has been eliminated in that part of the rail heated above the critical temperature during the welding process, that fully heat treated rail welded by this process will perform as well as standard control cooled rail in the weld zone. Oxy-acetylene pressure butt welds with control cooled rail are in use extensively without failures if properly welded. The failures noted in these tests are not different from those that have been experienced in laboratory tests and field service in welds made by this process with standard control cooled rail.

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  • Pagination: 3 p.

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Filing Info

  • Accession Number: 00097256
  • Record Type: Publication
  • Source Agency: Association of American Railroads
  • Report/Paper Numbers: ER-8
  • Files: TRIS
  • Created Date: Jul 29 1976 12:00AM