Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 39.

Thesis (M.S.)--Oregon Graduate Center, 1987.

Note:

Thesis (M.S.)--University of Illinois, 1942. / Reproduced from typewritten copy. Bibliography: leaves 128-131.

This study was an evaluation of thermite rail welding with the goal of the development of welds with improved mechanical properties. The first part of the study involved an in-depth evaluation of 14 thermite rail welds produced by the Department of Transportation using current production practices. These welds were produced using CrMo, CrV and Cr alloy rails, AREA CC rails (i.e., standard rails) and head-hardened rails which were welded with weld metal produced by the aluminothermic reaction of "standard" and "alloy" thermite charges. Temperature at various locations was measured during welding for both the rails and the weld metal. After welding, mechanical properties, macro- and microstructure, inclusion levels and residual stresses induced by the welding operation were all determined. Low impact properties and ductility (2-6 percent reduction in area) were observed in the thermite rail weld metal. These low properties were attributed to microstructure and, to a lesser extent, inclusion content. In order to improve the process by reducing the inclusion content, attempts were made to filter the molten thermite steel by passing it through zirconia/mullite filters. This was included in the second part of the study in which 9 plate welds we made using "standard" thermite charges. Filtering, at best, was only partly successful. However, it was observed that a 30 percent increase in yield strength and hardness was achieved in weld metal containing approximately 0.55 percent carbon and 0.06 percent vanadium. Normalization of the plate welds resulted in a significant improvement in the tensile ductility of as-cast weld metal. Weld metal of 0.55 percent carbon and 0.06 percent vanadium had ductilities in the range of 10-20 percent when the cooling rate exceeded 37 K(DEGREES)/min. through the transformation range. At cooling rates of four times this level, tensile properties equivalent to those of the "alloy" weld metal were obtained along with the enhanced tensile ductility. It was concluded that it is possible to produce a thermite weld with both improved strength and ductility by the judicious control of composition, the addition of microalloying elements and the application of an appropriate post-weld heat treatment, such as normalization.

Thesis (Ph. D.)--Oregon Graduate Institute of Science and Technology, 1996.

Thesis (Ph. D.)--Oregon Graduate Center, 1989.

Thesis, (Ph. D.)--Oregon Graduate Institute of Science and Technology, 1996.

Thesis, (Ph. D.)--Oregon Graduate Institute, 1997.

Thesis (Master of Engineering in Mechanical Engineering)--Cape Peninsula University of Technology, 2018. / South Africa’s railway system is the most highly developed in Africa. There are different kinds of transport systems in South Africa but rail transport is considered as one of an important element of the country’s transport infrastructure. In South Africa, over 2.4 million passengers make use of rail transport to get them to their destinations. However, evidence shows that train accidents have become a common occurrence across the country. Train-related accidents such as collision, derailments, platform change incidents and commuter accidents, cost South Africa over R400 million per year. The analysis of derailments indicates that the most significant single contributor to derailments is rail breaks. This contrasts considerably with prescribed relevant local and international benchmarks, which show a much lower percentage of derailments due to rail break. The frequency of derailments due to rail breaks in South Africa seems to be higher in the northern than the southern region. Furthermore, the proportion of rail breaks that result in derailment is considerably higher than the set benchmarks and therefore, if there is a rail break, then the probability of this translating into a derailment is astonishingly high. Equally, the high incidence of derailments due to rail breaks is affected by the train length and axle load and further exacerbated by the absence of track circuitry. Since derailments are a direct function of the incidence of rail breaks, focus is required to characterize the factors causing defects on rail lines. This study investigated steel rail material by characterising the piece of the damaged rail with the aim to gain a better understanding of the wear mechanism. Chemical composition analysis of steel rail sample was conducted with the use of a Scanning Electron microscopy. Hardness of steel rail was measured with a Vickers hardness tester. An Optical Microscopy was used to examine the microstructure features of the worn rail samples. This study discovered that the worn out rail, which was produced from high carbon steel with pearlite and ferrite microstructure, undergoes decarburization and a plastic deformation process. The decarburization process happens when the rail track is heated to 700 oC and above when the carbon atoms at the surface interact with the atmospheric gases and are removed from the steel as a gaseous phase. Plastic deformation is created when the iron atoms are heated above the elastic point resulting in the permanent movement of iron atoms.