Abstract
Following remarks are obtained from this investigation. 1) As for the influence of weld defects on the static strength of butt joints, the contribution ratio of the defective area is far larger than other factors. And for the percentage elongation of butt joints, the contribution ratio of the difference of welding procedures is almost as large as that of the defective area (see, Table 4). But the influence on both the static strength and the percentage elongation of butt joints doesn't differ from the difference of the kinds of weld defects induced artificially. 2) For the influence of weld defects of the same total defective area on the static strength and the percentage elongation of butt joints, there are no substantial differenced between joints with single defect and joints with multidefects. 3) The uniform elongation of butt joints is not influenced by the mode of fracture, ductile mode or brittle like mode. And uniform elongation over 5% has been obtained in joints whose defective area is less than 2% of the gross sectional area of the joints. 4) As for butt joints whose plate thickness is thin or medium, the assessment of welded joints by the length of weld defect can be possible with some grounds. But as for thick plate, the assesment of welded joints only by the length of weld defect has not reasonable grounds. 5) As the height of flaw echo has little correlation with the static strength of butt joints, the subdivision of the range of echo height is meaningless for the assessment of welded joints.
