Internal structural discontinuities are categorized into which two groups?

Internal structural discontinuities are categorized into which two groups?

• A. spherical or laminar
• B. radial or axial
• C. planar or spherical
• D. thick or thin

Answer: (A)

The main idea is that defect shapes determine how we classify internal discontinuities. Defects that are roughly round or pocket-like—caused by trapped gas or voids—are treated as spherical, a volumetric type. Defects that stretch out into a sheet or along a plane—like layered flaws along the weld, slag inclusions, or lack of fusion—are called laminar, a planar type. This geometric distinction matters because it affects how the defect shows up in inspection, how it might affect strength or fatigue, and what acceptance criteria apply. In radiographs, spherical defects tend to appear as small, round indications, while laminar defects show up as elongated, planar indications. So the two groups are spherical (volumetric) and laminar (planar) discontinuities.

The main idea is that defect shapes determine how we classify internal discontinuities. Defects that are roughly round or pocket-like—caused by trapped gas or voids—are treated as spherical, a volumetric type. Defects that stretch out into a sheet or along a plane—like layered flaws along the weld, slag inclusions, or lack of fusion—are called laminar, a planar type. This geometric distinction matters because it affects how the defect shows up in inspection, how it might affect strength or fatigue, and what acceptance criteria apply. In radiographs, spherical defects tend to appear as small, round indications, while laminar defects show up as elongated, planar indications. So the two groups are spherical (volumetric) and laminar (planar) discontinuities.