Mechanical Properties of Butt Weldments Made with Q345B Steel and E5015 Electrodes at Different Temperatures

The current design standards provide strict recommendations to ensure the quality of welds. This study investigates the mechanical properties of welds subjected to elevated temperatures by performing a steady-state tensile test on butt weldments composed of Q345B base metal and E5015 electrodes. The experimental results include the elastic modulus, yield, ultimate strength, and ductility of the butt weldments at temperatures from 20°C to 800°C. Comparison of the results shows that the welding heat-affected zone (HAZ) is vulnerable to fracture when subjected to reheating above 500°C. The comparison indicates that current standards are nonconservative in predicting the deterioration of the elastic modulus. Below 500°C, current Australian recommendations are still applicable to the reduction factors of the yield strengths at a strain level of 1.5% or 2.0%. At 500°C and higher, the butt welds are considered unsafe relative to the recommendation of the current design standards for the reduction factors of the yield strengths. Finally, it is still risky to use the recommendations of the current design standards directly to predict the mechanical properties of butt welds at a high temperature, particularly in the range of 500°C–800°C.