The Impact of Low-Temperature Welding on the Quality of Pipe Trusses

The Impact of Low-Temperature Welding on the Quality of Pipe Trusses

Low-temperature welding can lead to faster cooling rates in the weld, increasing susceptibility to cold cracking and potentially causing crystallization cracking and brittle fracture. To ensure quality, measures such as preheating (within a 500℃ range), using insulated shelters for wind and snow protection, and controlling interpass temperature are necessary. Low-hydrogen electrodes should also be selected to reduce hydrogen-induced cracking.

Process Optimization Directions

Deformation and residual stress can be effectively reduced by using a reasonable welding sequence (center first, then sides; large diameter pipes first, then small diameter pipes) and VSR (Vibratory Stress Relief) aging vibration to eliminate stress. In addition, ultrasonic testing and magnetic particle inspection can ensure that the weld is free of defects and meets the GB50205 standard.