Study On Fatigue Property Of Steel 508-3

Fatigue invalidation of weldment is common in engineering. Nuclear power vessels and pipeline adopt welding technology, which needs close attention to the fatigue property of the welds. The material of this research is 508-3 steel used in the pipelines of pressure vessels of nuclear power plants. By practical experiments and mature theory, this paper analyzes fatigue fracture, metallographic examination, data of low-cycle fatigue experiment under tensile-tensile load and the statistic on fatigue life of 508-3 steel by three-parameter Weibull distribution and evaluates the fatigue property of steel 508-3.Following are the main contents of this paper:(1) To attain the longevity probability histogram of division of the factures in different facture places and a number of the weldments by statistic of the data of 508-3 steel under 220 Mpa in fatigue life experiment and estimate the life distribution of 508-3 steel under the above load.(2) To study the metallurgical structure of the material in different position. By comparison of different metallurgical structures, deduce the reasons of the facture in different position.(3) By microscopical observation of facture in different positions, obtain the reasons of the fatigue factures and their surface topography and compare the similarities and differences of different fatigue factures.