Suck back porosity is due to_________________?
Correct answer: B. Hot spot
- A. Attached impurities on undersurface of casting
- B. Hot spot
- C. No rapid cooling
- D. Inadequate melting temperature
Explanation
Suck-back porosity is shrinkage porosity caused by a hot spot, usually at the sprue-casting junction, where solidification is delayed and the area cannot receive liquid metal. The defect is therefore linked to localized overheating rather than simply slow cooling.
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