THERMIT WELDING METHOD FOR BAINTING STEEL RAIL

摘要

PROBLEM TO BE SOLVED: To control the residual stress distribution at the toe part of reinforcement which is prone to cause fatigue fracture, in the thermit welding of bainitic steel rail, and to provide a thermit weld joint having a high fatigue strength. SOLUTION: The thermit welding is such that two rail ends are oppositely installed at a certain interval and welded by flowing a high temperature molten metal in the space which is formed by a refractory casting mold to surround the interval and its circumference between the rail ends; after the molten metal is completely solidified and cooled so that the surface temperature of the welded metal in the rail head becomes 300 deg.C or below, the surface of the rail bottom leg including the solidified part is reheated to 400-700 deg.C.