Abstract
The paper aims to evaluate the fatigue behavior and its probabilistic properties in welded SM490A steels, which is utilized in high speed train, under low temperatures. For the goal, the tensile and fatigue tests are performed under displacement control mode and constant amplitude loading cycles, respectively at various temperatures (233K, 263K, 293K). The static strengths for base and welded materials are increased with the decrease in temperature but, the welded material has a considerable amount of scatter. Also, the fatigue behaviors are greatly influenced by the test temperature for both materials. Especially, the welded material exhibits severe reduction of the fatigue limit compared with the base material. The statistical properties of fatigue life are investigated through P-S-N (probabilistic S-N) approach and the curves are well in conformance with the experimental results. Also, resulting from the P-S-N curves, the variations of fatigue life are greatly influenced by the temperature and this tendency is more remarkably in the welded material.
