Abstract
The welding method which provides the welded joint with high performances, especially high bending fatigue strength, at as-welded condition has been studied in consideration of welding residual stress which has an effect on fatigue properties.
The results of this study are as follows:
(1) The formation of welding residual stress is subjected to three internal stress balances, that are a) the stress balance between the surface and the inside at final welding section followed by the expansion through transformation and the heat contraction, b) the stress balance along the longitudinal direction followed by the heat expansion and contraction of weld metal and HAZ, c) the wholly secondary stress balance followed by the solidification of weld metal and the heat contraction during the welding progress from rail base to rail head.
(2) It was found that there is the difference in residual stress between the high C weld and low C-low alloy weld and that the good residual stress distribution of welded joint can be obtained by the combination of both weld metals, and the new welding method has been developed.
