Difficulty: Easy
Correct Answer: salt bath furnace.
Explanation:
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:
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:
Identify heating medium: a liquid (molten salt).Relate process to common equipment: salt bath furnace.Select the corresponding option.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:
Blast furnace: countercurrent solid-gas reactor for ironmaking, not liquid bath heating.Steam boiler: produces steam; not a workpiece heat-treatment bath.Annealing furnace: typically a gaseous atmosphere or vacuum, not a liquid immersion.Common Pitfalls:Confusing quench tanks (cooling) with salt baths (heating). Salt baths heat first; quench tanks cool later.
Final Answer:salt bath furnace.
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