Abstract
According to the specification for Highway Bridges, the minimum weld size is determined so that the leg length, S, satisfies the condition of S>=√2t, where t is the thickness of a plate. However, when the thickness exceeds 40mm this standard requires the S value larger than the maximum of one pass welding, which could lead to the decrease of the welding execution efficiency. Why this standard regulates the weld size is to avoid cold cracking by escaping the rapid cooling. But escaping the rapid cooling is not the only method to avoid cold cracking. In this study, we examine the cold cracking susceptibility and the HAZ hardness distributions of the fillet welds using 50mm thick plates whose PCM ranges from 0.21% to 0.27%. We also carry out the heat conduction analysis to evaluate the effect of the test piece size. Using the present results, we discuss the validity of the today's standard of the √2t regulation.
