erosion scab

erosion scab

[ə′rō·zhən ‚skab]
(metallurgy)
A defect in the form of a solid mass of sand and metal that occurs when molten metal has been agitated or boiled or has partially eroded in the sand of a metal-casting mold.
References in periodicals archive ?
Without sufficient hot strength, high metal velocity washes the mold material away, leaving an erosion scab.
Depending on a foundry's ability to control sand temperature, casting results can range from high scrap (sand inclusions, washes or erosion scabs, surface roughness, pinholes, crushes and broken molds) to complete loss of system control.