Hi all We are currently conducting Charpy V Notch Test to the Longitudinal Weld Seam of a Steel Pipe. The specimens we have tests are of two different size : full size (10mm x 10mm x 55mmL) and 2/3 size (6.7mm x 10mm x55mmL). We have conducted the tests severally time at -30degC. The results of the 2/3 size were consistently larger than that of the full size. We are trying to explain this strange situation. It is because larger the cross sectional area should require more impact energy but in this case it is the other way round. Would like to seek opinion / comment on this situation. More info about the pipe is given below : The longitudinal weld seam was welded by submerged arc welding during the pipe manufacturing. The bevel for the longitudinal weld is of x-groove (or double v-bevel), i.e. the submerged arc welding are to be carried out on both the external face and internal face. The pipe is 600mm diameter and 12.7mm thick. Thank you very much.