In the previous report, the effect of contour of fillet weld on the mechanical behaviour and strength of fillet welded joint was explained. The present report explains the effect of fillet size and depth of penetration on them. A model specimen, having a profile of cruciform fillet welded joint, is used for the experiments. Strain distributions in fillet weld are measured by using the Moire method. Experiments are performed in the range from 5 mm to 30 mm leg length and from -2 mm to 20 mm depth of penetration. The results obtained are as follows;
1) The yield strength of fillet welded joint is not affected by fillet size but the maximum strength decreases with incresae of fillet sixze.
2) The yield strength and the maximum sterngth of fillet welded joint are represented as a function of the penertation angle θp, and they increase with increase of the penetration angle θp.