Key Points of Welding Technology for Bailey Steel Bridge Production

Pin hole area: This is the most complex and critical area in terms of force application for the Bailey bridge (such as the end of the chord members, the joint of the diagonal braces, etc.). The welds in this area (especially the fillet welds) must ensure penetration and strength to avoid stress concentration. The welding sequence and deformation control must be particularly precise to ensure the accuracy of the pin hole positions. The NDT requirements for this area are usually the highest (such as 100% UT + MT).

Butt welds: The butt welds of chord members, longitudinal beams, etc. require full penetration (usually Grade I welds), and must ensure penetration with high internal quality requirements (such as UT testing).

Fatigue performance: The Bailey bridge is subjected to dynamic loads from vehicles, and the fatigue performance of the welds is crucial. It is necessary to strictly control the weld profile (avoid sharp notches), internal defects (especially cracks, lack of fusion), undercut, and other stress concentration sources. Adopting low-hydrogen welding processes, controlling heat input, and ensuring penetration are key to improving fatigue strength.

Deformation control: The overall straightness of the truss panels and the accuracy of the pin hole spacing directly affect the on-site erection speed and the bridge alignment. The welding sequence, fixture design, and rigid fixation are the core.

Traceability: Establish a complete weld quality record and traceability system (including the furnace batch number of the base material, the batch number of the welding materials, the welder's number, welding parameter records, inspection reports, etc.) to ensure that the quality responsibility of each critical weld can be traced.

Environmental control: The welding environment should be kept dry and free of drafts (especially important for gas shielded welding). When the ambient temperature is too low (such as <5°C) or the humidity is too high, protective measures should be taken (such as setting up wind and rain shelters, increasing preheating temperature, etc.).