The indication that appears dish-shaped and extends in a spoke formation on an aluminum plate is known as:

The indication described as dish-shaped and extending in a spoke formation on an aluminum plate is identified as a crater crack. This type of crack is generally associated with the solidification process during the casting of aluminum alloys and can often be attributed to rapid cooling and solidification, leading to tensile stresses that result in the characteristic appearance.

Crater cracks form as the molten metal cools and shrinks, and the surface tension causes them to create a dish-like appearance surrounded by radiating cracks. Recognizing this specific type of defect is crucial in visual testing as it can indicate problems related to material selection, processing conditions, or heat treatment methods that could compromise the integrity of the aluminum component.

Understanding the distinct characteristics of crater cracks helps inspectors to assess the quality of the aluminum plate accurately and make informed decisions regarding its usability in construction or manufacturing processes.