Case hardening and through hardening
Case hardening and through hardening are two metal heat treatment
techniques commonly used by MCC.
Each method is employed for different purposes and follows distinct processes.
Case Hardening
Case hardening is primarily used to increase the surface hardness of low
carbon steel/low carbon alloy steel.
The process includes the following steps:
Heating:
The workpiece is heated to the carburizing temperature range and placed
in a carbon-rich environment (such as gas, liquid, or solid medium).
Carburizing: Carbon atoms diffuse into the surface of the steel, forming a high-carbon hardened layer,
which significantly increases surface hardness after quenching.
Quenching:
The workpiece is rapidly cooled in water or oil, forming a hardened
surface layer while the interior remains softer to maintain
toughness.
Tempering:
After quenching, the workpiece undergoes low-temperature tempering to
reduce internal stress and enhance toughness.
The purpose of case hardening is to give the workpiece a high-hardness
surface while maintaining toughness in the interior,making it suitable for
parts that require high wear resistance, such as pins, bushings, and
rollers.
Through Hardening
Through Hardening is a comprehensive heat treatment method aimed at
enhancing the overall mechanical properties of the steel.
The process includes:
Heating:
The steel is heated to above its critical temperature, transforming it
into an austenitic structure.
Quenching:
The workpiece is rapidly cooled in water or oil, transforming it into a
martensitic structure, which results in overall hardening of the
material.
Tempering:
After quenching, the workpiece undergoes a medium-temperature tempering
process to reduce internal stress and enhance both strength and
toughness.
The purpose of through hardening is to provide the workpiece with high
strength and toughness,
making it suitable for components such as chain plates and pins that need
to withstand chain tension.
Differences in Roller Chain Applications
Category
Case Hardening
Through Hardening
Applied Parts
- Pin
- Bushing
- Roller
(wear-resistant surface)
- Pin (high tensile strength)
- Chain Plate (excellent fatigue resistance)
Primary Purpose
Increase surface hardness and enhance wear resistance
Improve overall strength and toughness, capable of withstanding
high loads and fatigue stress
Treatment Results
High surface hardness and strong wear resistance
High overall strength, toughness, capable of withstanding tensile
and impact stresses
Between the Two Treatments and Roller Chains
In summary, Case Hardening and Through Hardening play complementary roles
in the manufacturing of industrial roller chains.
Case hardening enhances the surface hardness of components like pins,
bushings, and rollers,
providing excellent wear resistance and ensuring the chain's long-term
durability in high-wear environments.
On the other hand, Through Hardening improves the overall strength and
toughness of chain plates and pins, allowing the chain to withstand heavy
loads and impact stresses during repetitive operations. The combination of
these heat treatment methods ensures that industrial roller chains are both
durable and reliable, maintaining stable performance in demanding industrial
conditions.