Method for post-weld heat processing of rail welded joint

A technology of post-weld heat treatment and welded joints, which is applied in the field of rail welding, can solve the problems of non-eutectoid rails and PG4 heat-treated rails, and achieve the effects of good matching of joint strength and toughness, good stability, and stable welding quality
CN106544933AActive Publication Date: 2017-03-29PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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Patent Information

Authority / Receiving Office
CN Β· China
Current Assignee / Owner
PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
Publication Date
2017-03-29

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Abstract

The invention relates to the field of rail welding and discloses a method for post-weld heat processing of a rail welded joint. The method comprises the steps that first cooling is conducted to the to-be-cooled rail welded joint obtained through welding till the temperature is lower than 400 DEG C; then, the rail welded joint obtained after the first cooling is heated to a temperature between 860 DEG C and 930 DEG C; and second cooling is then conducted to the rail welded joint till a tread face temperature of the joint is between 410 DEG C and 450 DEG C, wherein the rail welded joint is a welded joint of a 75kg / m hypereutectoid steel rail and a pearlite steel rail. The method disclosed by the invention is used for the post-weld heat processing of the welded joint of the hypereutectoid steel rail and the PG4 heat-processing steel rail; and the heterogeneous rail joint has fewer internal defects and stable welding quality, and can satisfy requirements for passing tests such as a fatigue test, a stretching and impact test and a static bending test.
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Description

technical field

[0001] The invention relates to the field of rail welding, in particular to a method for performing post-weld heat treatment on rail welded joints. Background technique

[0002] Hypereutectoid steel rail is a new type of steel rail developed in recent years. The carbon content of hypereutectoid steel rail is generally in the range of 0.90-1.0% by weight, and its microstructure is intergranular secondary cementite + pearlite. The mixed structure is the top steel rail with the highest strength (1350MPa) and hardness (400HB-420HB) in the world. The structure of pearlitic steel rail is pearlite, and the representative pearlitic steel rail is PG4 heat-treated steel rail. PG4 heat-treated steel rail (also known as U78CrV, referred to as PG4 steel rail) has a carbon content in the range of 0.72-0.82% by weight, a microstructure of pearlite structure, a strength equivalent to that of a hypereutectoid steel rail, and a slightly lower hardness of 20HB. The structures...

Claims

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