1.⁠ ⁠Heating Stage

This is the first and most crucial step, aiming to raise the metal to the desired temperature uniformly.

Key Objectives:
• Avoid internal stress, distortion, or cracking.
• Ensure even thermal expansion across the part.

Factors affecting heating rate:
• Thermal conductivity of the metal: High-conductivity metals heat faster.
• Condition of the metal: Previously hardened or stressed parts require slower heating.
• Size & geometry: Large or irregular cross-sections must be heated more gradually to prevent thermal imbalance.

At Hindustan Foundries, we use calibrated furnaces with controlled gas atmospheres to ensure precise and uniform heating.

2.⁠ ⁠Soaking Stage (Holding Time)

Once the desired temperature is reached, the metal is “soaked” at that temperature to allow internal structural transformation.

Purpose:
• Achieve thermal uniformity throughout the part.
• Enable phase changes within the metal’s microstructure.

Soaking Time Depends On:
• Chemical composition (e.g., carbon or alloy content).
• Mass and section size of the component.
• Design complexity (more complex parts may need stepped preheating).

We calculate optimal soak durations using metallurgical data and part geometry to avoid grain coarsening or overheating.

3.⁠ ⁠Cooling Stage

Cooling returns the metal to room temperature in a controlled manner, with or without quenching, depending on the material and desired result.

Cooling Options Include:
• Air cooling
• Oil quenching
• Water or brine quenching
• Controlled furnace cooling

Key Considerations:
• Rapid quenching generally hardens steel (e.g., in water or oil).
• Slow cooling can be used for annealing or stress-relieving.
• Improper quenching can cause cracks or warping, especially in complex parts.

We select the cooling medium (air, oil, water, brine) based on the metal type and target hardness, toughness, or ductility.