Foundry sand properties — name for the ability of grains to stick together In moulding practice, which property term describes the tendency of sand grains to stick together due to bonding action, enabling the mould to retain its shape?

Introduction / Context:
Sand moulds must balance several properties: strength to hold shape, permeability to vent gases, refractoriness to withstand heat, and collapsibility to ease shake-out. Precise terminology avoids confusion when diagnosing mould failures like scabbing, erosion, or blows.

Given Data / Assumptions:

• Moulding media: silica sand with binders (clay, organic resins, etc.).
• Focus: the property that makes sand particles stick to each other.
• Application: green-sand and dry-sand moulds.

Concept / Approach:
Cohesiveness is the internal bonding strength between sand grains that allows a mould to be rammed and then stripped from the pattern without crumbling. It is distinct from adhesiveness, which is the tendency of sand to stick to another surface (like a pattern or flask). Collapsibility is the opposite tendency after pouring, and permeability measures gas flow through the sand.

Step-by-Step Solution:

Verification / Alternative check:
Strength tests (green compressive strength) correlate with cohesiveness for green sand systems.

Why Other Options Are Wrong:

• Collapsibility: ability to disintegrate after solidification.
• Permeability: gas passage property, not bonding.
• Adhesiveness: sticking to other materials, not grain-to-grain.
• Refractoriness: resistance to high temperature, unrelated to sticking.

Common Pitfalls:
Interchanging adhesiveness and cohesiveness; over-bonding that reduces permeability and causes gas defects.

Final Answer: