INFLUENCE OF WELDING HEATING ON FATIGUE STRENGTH OF HOLLOW STRUCTURES FROM HIGH-STRENGTH FINE-GRAINED STEELS

摘要

Welding trials and technological assessment of square hollow sections of 80 × 80×10 mm size from steel of SG69Q grade were performed. Welds were assessed on macrosections, by hardness measurement, their static bending and impact testing. In order to determine fatigue strength at bend testing with cycle asymmetry factor R = 0.5 under the conditions of rail transport works, these sections were joined by mechanized gas-shielded solid and flux-cored wire welding. Comparison of section testing results and their compliance to normative requirements was performed. Recommendations on application of various sections in structures with cyclic loading are given.