Fatigue Resistance of Fillet Welds of Traction Rod Brackets on a Locomotive Bogie Based on International Union of Railways Standards and Improvement Measures Adopted

To solve the problem of fatigue failure in fillet welds traction rod brackets on locomotive bogies a given model, cause for and improvement method were studied. The results show that when there is maximum clearance at weld roots, incomplete fusion sidewalls, pores allowable ISO 5817 standard, stress amplitude separately increases by 70~97%, 53~55%, 40~46%, 19~34%. Despite this, various types defects size are present alone, static strengths with throat depth 6 mm bracket can still meet requirements UIC615-4 standard. In practical welds, including fusion, very likely to occur same time, which may induce within original design life. According frame brackets, strengthening scheme increasing 8 was designed. Calculation new structures subjected overall post-weld stress-relief thermal treatments, decreases 5~29% from mm. For service increased through repair welding, peak residual root after welding reach 383 MPa. Because treatments cannot be performed repair-welded structures, strength UIC615-4; therefore, local have welded zone. guiding significance treatment locomotives performance suggest current standard relatively conservative.