Question

Which of the following is not a casting defect?

• A. Fin
• B. Scab
• C. Ingate
• D. Hot tear

Hint:

To distinguish between casting terms, remember that the "gating system" (pouring basin, sprue, runner, ingate) and "riser" are planned parts of the mold setup. Defects are unplanned outcomes like cracks (hot tear), excess material (fin), or surface flaws (scab, blowhole).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
A casting defect is an undesired irregularity in a metal casting that deviates from the design specifications. The question asks to identify which of the given terms is a part of the casting process itself, rather than a defect.

Step 2: Detailed Explanation:
Let's define the terms:

• (A) Fin: A fin (or flash) is a thin, unwanted projection of metal on the surface of a casting, typically occurring at the parting line where the two halves of the mold do not fit together perfectly. This is a common casting defect.

• (B) Scab: This is a surface defect where a thin layer of metal is separated from the main body of the casting by a layer of sand. It is caused by the sand on the mold surface flaking off due to high heat. This is a defect.

• (C) Ingate: The ingate is the final part of the gating system, the channel through which the molten metal actually enters the mold cavity. It is a necessary and intentionally designed component of the mold, not a defect. After the casting solidifies, the gating system (including the ingate) is cut off and removed.

• (D) Hot tear: This is a crack or fracture that forms in a casting while it is still hot and weak, caused by the metal's inability to shrink freely during cooling. This is a serious casting defect.
From the definitions, Fin, Scab, and Hot tear are all casting defects, whereas an Ingate is a functional part of the mold's gating system.

Step 3: Final Answer:
An ingate is a component of the gating system used to fill the mold and is not a casting defect.