Objectives

∙ To reduce hardness and increase ductility, facilitating forming, turning, planing, cutting, and drilling operations.
∙ To relieve residual stress induced by the forming process.
∙ To refine and homogenize the microstructure after forming.

Method
Heat the workpiece to a specified temperature, then allow it to cool slowly inside the furnace (furnace cooling).

Objective

∙ To refine and homogenize the grain structure.
∙ To reduce residual stresses within the workpiece that may have resulted from previous forming processes, before further forming or subsequent hardening operations.

Process Description
The workpiece is heated to a specified temperature and then allowed to cool in still air.

Objective

∙ To increase the overall hardness of the workpiece, enhance wear resistance, and improve durability during service.

Process Description
The workpiece is heated to the specified temperature and then rapidly cooled by quenching in a suitable quenching medium to achieve a cooling rate higher than the critical cooling rate.
After quenching, the workpiece undergoes tempering to reduce brittleness and improve toughness.

Objective

∙ To increase the overall hardness of the workpiece, enhance wear resistance, and improve durability during service.

Process Description
The workpiece is heated to the specified temperature and then rapidly cooled (quenched) in a suitable quenching medium to achieve a cooling rate higher than the critical cooling rate.
After quenching, the workpiece undergoes tempering to reduce brittleness and increase toughness.

Key Advantages of Vacuum Heat Treatment

∙ Provides excellent control over the cooling rate, resulting in reduced distortion and warping.
∙ Prevents oxidation and decarburization during heating.
∙ Produces a clean and bright surface finish on the workpiece after heat treatment.

Objective

∙ To increase the surface hardness of the workpiece, thereby improving wear resistance and fatigue strength, while maintaining a tough and ductile core capable of absorbing impact loads effectively.

Process Description
Low-carbon steel or low-alloy steel components are subjected to a controlled process in which carbon is introduced into the surface layer (carburized).
After achieving the desired case depth, the workpiece is subsequently hardened (quenched) to obtain a hard surface with a tough, ductile core.

Objective

∙ To increase the surface hardness of the workpiece, improving wear resistance and fatigue strength, while maintaining a tough and ductile core capable of absorbing impact loads effectively.

Process Description
Low-carbon steel or low-alloy steel components undergo a process where carbon is introduced specifically into the surface layer (carburized), followed by quenching to harden the entire workpiece.

Key Advantages of Vacuum Carburizing

∙ Ensures uniform gas distribution throughout the furnace, resulting in consistent and uniform case depth hardness across all workpieces.
∙ Suitable for complex-shaped components, including parts with small holes or intricate geometries.
∙ Minimizes oxidation and surface contamination, producing cleaner and higher-quality surface finishes.

Objective

∙ To increase the surface hardness and improve wear resistance of the workpiece.
∙ To enhance fatigue resistance.
∙ To reduce friction on the contact surface (improving surface lubricity).
∙ To minimize distortion since the process is performed at a lower temperature compared to carburizing.

Process Description
Low-carbon steel components undergo a controlled process in which both carbon and nitrogen are introduced into the surface layer, followed by hardening (quenching) of the entire workpiece.
One key advantage is that the heat treatment temperature is lower than that of carburizing, resulting in reduced distortion.

Objective

∙ To increase surface hardness and improve wear resistance of the workpiece.
∙ To reduce friction on the contact surface (enhancing surface lubricity).
∙ To provide improved corrosion resistance.

Process Description
Carbon and nitrogen are introduced into the surface layer of the workpiece, forming a nitrogen-rich compound layer.
Since the treatment temperature is relatively low (approximately 500–580°C), the process results in minimal distortion.

Objective

∙ To increase hardness, toughness, and overall strength of the workpiece.
∙ To improve mechanical flexibility.
∙ To enhance fatigue resistance.

Process Description
The workpiece is heated to the specified austenitizing temperature and then cooled at a rate faster than the critical cooling rate down to a temperature above the Ms point.
The part is then held (soaked) at this temperature until the austenite transforms into a bainitic microstructure.

Advantages of Austempering

∙ The transformation from austenite to bainite occurs at a constant temperature, resulting in low residual stress.
∙ The process significantly reduces distortion and warping of the workpiece.