What is a discontinuity that can be found in rolled plates?

Laminations represent a significant type of discontinuity found in rolled plates, primarily due to the manufacturing process. During the rolling of steel plates, non-metallic inclusions, such as sulfides or oxides, can become trapped within the material, leading to the formation of layers or "laminations." These laminations can compromise the mechanical properties of the plate, including its strength and ductility, making them a critical concern in applications where structural integrity is essential.

The presence of laminations can cause issues such as reduced fatigue strength and increased brittleness, which may lead to failures in service. Detecting laminations often requires non-destructive testing methods, making it crucial for quality control in industries that utilize rolled plates, such as construction and manufacturing.

Other forms of discontinuities like tar contamination, surface scratches, and welding seams also impact the integrity of materials, but they do not represent the internal structural defects associated with rolling processes in the same way that laminations do. Each of these has distinct origins and implications, but laminations are specifically tied to the processes and materials involved in the creation of rolled plates.