Abstract
The requirement of the minimum length of tack welds is specified to prevent the occurrence of heel cracking from the root of fillet welds. Heel crackings in the fillet welds of many 500MPa class steels with different chemical compositions are studied experimentally by using a T-shaped cracking method with various weld lengths, leg lengths, electrodes, temperatures, restrains and plate thicknesses. The level of carbon equivalent is the governing factor for the occurrence of heel cracking and the length of welds is not a dominant factor.
