Foundry gating design — purpose of the pouring basin: In sand casting, a pouring basin at the top of the sprue primarily functions as a reservoir and flow stabiliser for the incoming molten metal. Evaluate the statement.

Introduction / Context:
A well-designed gating system reduces turbulence, entrained air, and inclusions. The pouring basin is the first element the metal encounters and therefore plays a key role in delivering a steady, clean stream to the sprue, runner, and gates.

Given Data / Assumptions:

• Conventional sand casting process.
• Pouring basin located above the sprue.
• Goal: smooth, controlled flow into the mould cavity with minimal defects.

Concept / Approach:
The pouring basin acts as a small reservoir buffering fluctuations in ladle pour rate. It allows initial metal to collect, dross to skim off, and the sprue to run full, which reduces aspiration (air being sucked in). By maintaining a head of metal, the basin stabilises pressure and flow through the sprue, producing more laminar conditions downstream.

Step-by-Step Solution:
Identify function: buffer and reservoir at sprue entrance.Relate to defect reduction: reduces turbulence and air aspiration.Note secondary benefits: facilitates skimming of slag/oxide films.Therefore, the statement that it acts as a reservoir is correct.

Verification / Alternative check:
Practical trials show moulds with a proper basin achieve faster sprue fill and fewer misruns and inclusions than those poured directly into the sprue.

Why Other Options Are Wrong:
Limiting to non-ferrous or bottom gating is unnecessary; benefits apply widely.

Saying it is only for dross trapping ignores its reservoir and flow-regulation roles.

Common Pitfalls:
Omitting the basin, causing air aspiration; undersizing the basin, which cannot maintain a head; poor skimming leading to inclusions.

Final Answer:
Agree