weld mark

例句：

1. 1.The weld marks on the metal surface are visible even under a microscope.
   金属表面的焊缝痕迹即使在显微镜下也能看见。
2. 2.The engineer carefully marked each weld line to ensure accuracy.
   工程师仔细地标出了每一条焊缝线，以确保准确性。
3. 3. Welding marks can be used as evidence in court for the integrity of the workmanship.
   焊接痕迹可以作为法庭上证明工艺完整性的证据。