Nondestructive Testing and Evaluation Methods for Rail Welds in Japan

概要

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In Japan, four types of welding methods, that is, flash welding, gas pressure welding, enclosed arc welding and thermite welding are applied to rail welding. All welds are inspected by nondestructive inspection right after welding in order to assure the reliability of rail welds. However, rail weld failures, which are initiated from weld discontinuities, rarely occur. It is thought that welds performed by fusion welding such as enclosed arc and thermite welding have less reliability than those by flash and gas pressure welding, because some weld discontinuities are easily generated. In this paper, the features of rail weld failures and the inspection methods for rail welds in Japan are introduced. Moreover, the improvements of the ultrasonic inspection method for preventing rail weld failures are discussed. Consequently, the double-probe technique of ultrasonic inspection method is suitable to detect discontinuities in rail welds. The relationship between weld quality and property, such as rupture load and fatigue strength, is clarified by applying this method to rail fusion welds. Rail weld failures have gradually decreased since the adoption of this inspection method to fusion welds.
公益社団法人鉄道総合技術研究所の論文