Mode of heat transfer with a surrounding liquid medium: Heating a part submerged in a high-temperature liquid bath occurs in which furnace type?

Introduction / Context:
Some heat-treatment operations require rapid, uniform heating with excellent surface contact. Salt bath furnaces use molten salt as a heat-transfer medium, immersing the workpiece to achieve fast and controllable heat penetration.

Given Data / Assumptions:

• Workpiece is fully or partly submerged in a liquid bath.
• Liquid is typically molten salt at elevated temperature.
• Objective is efficient, uniform heating.

Concept / Approach:
Heat transfer by forced contact with a liquid (molten salt) greatly increases the convective coefficient versus air or flue gas. This reduces temperature gradients within the part and minimizes oxidation compared to direct flame environments.

Step-by-Step Solution:

Verification / Alternative check:
Salt baths are standard for austempering, martempering, and some carburizing steps; the liquid fully envelops the workpiece for uniform heating.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing quench tanks (cooling) with salt baths (heating). Salt baths heat first; quench tanks cool later.

Final Answer:
salt bath furnace.