Induction hardening is a type of heat-treating process
that typically subjects a metal part under induction heating and quenching. After
conducting this specific process, the metal part is intended to undergo a
martensitic formation, allowing it to obtain features and properties that it
does not possess before.
The process of induction heating starts by placing a
metal part near a copper coil that has a significant level of alternating current.
Through eddy current and hysteresis losses, the said coil can generate heat
that is directed at or near the surface of the metal part. Subsequently, the
metal part is directed or submerged under a water-based quench, which then
initiates its aforementioned martensitic formation.
Induction hardening can bring numerous benefits to the
processing of different metal parts. The same process, however, also share some
disadvantages that manufacturers may encounter along the way.
Advantages of Induction Hardening
Improved Wear
Resistance: One of the advantages of
induction hardening is that it can effectively improve the wear resistance of a
metal part. Metal parts that have been annealed or treated to a softer
condition can significantly obtain improved wear resistance once they undergo
this process. After all, any improvement of a part’s hardness can likewise
improve its wear resistance.
Increased Fatigue
Life: The residual compressive stress at the surface of a
part out of induction hardening can easily obtain a huge improvement over its
strength and fatigue life. The induction hardening allows the part to obtain a
hardened structure that occupies more volume than its core.
Customised Hardness
Level: With induction hardening, metal parts can now be
tempered easily, granting manufacturers the ability to customise their hardness
level based on their set requirements. The more these metal parts are tempered,
the lower the hardness and brittleness will be.
MinimisedWarpage: Another advantage of induction hardening is that it does not warp the
metal parts significantly. You see, other types of hardening processes are
known for warping the metal part and its respective surfaces. But with
induction hardening, you can easily process materials without significant and noticeable
warpage.
Notable Low Costs: When it comes to overall costing, induction hardening can be done
without spending too much money. The process likewise does not require
expensive metal parts. So, if you are thinking of processing low-cost steels,
then you may proceed with induction hardening.
Disadvantages of Induction Hardening
Occurrences of
Cracking: As for the disadvantage of induction hardening, the
entire process is more prone to causing some cracks on the surfaces of metal
parts compared to other heat treatment processes. Induction hardening can also
produce hot spots at specific features like keyways, grooves, cross holes,
threads, and many more.
Greater Distortion
Levels: Aside from cracking issues, the process of induction
hardening can also cause more distortion on the metal parts than other heat
treatment processes. This distortion is brought by the martensitic
transformation that the part receives during the process.
Limitation on
Materials: Despite the notable low costs of
induction hardening, this process can only work on limited materials. This
process can only work with materials that contain enough carbon and other
elements so they can support all the features caused by the martensitic
transformation.
For more information about induction hardening, you
can call us at Alpha Detroit Heat Treatment.
To get the desired properties of metal materials,
metallurgists would normally place them under heat treatment. Heat treatment is
a group of industrial and metalworking processes that are used in changing and modifying
the properties of a metal or any other material. The processes involved in heat
treatment are constantly enhanced by different metallurgists to obtain improved
results and achieve cost-efficiency.
Some Effects of Heat Treatment Processes
Heat treatment processes bring numerous effects to
metal materials that undergo them. For one, some processes can make metal
materials soft, while others can boost their overall hardness. Alternatively,
the electrical and heat conductivity of numerous metal materials may also
improve due to specific heat treatment processes. Even the chemical properties
of these metals can be altered once they are placed under numerous heat
treatment procedures. Stresses due to earlier heat treatment processes may
likewise be alleviated and relieved once they are placed under other heat
treatment processes.
Understanding the Technological Process
Understanding the technological process of heat
treatment is key to the successful alteration and modification of metal
materials. Most of the heat treatment processes are carried out by three
essential steps: heating, heat preservation or holding, and cooling. These
steps are usually interlinked. However, the inclusion of some of these steps
would still vary based on the metal that is intended to be processed.
Heating: Heating is typically carried out first when placing metals under heat
treatment. This step is done in line with a prescribed thermal profile of a
metal or an alloy under a controlled atmosphere through different heat sources
such as liquid, gas fuels, and electricity. At this point in heat treatment, an
alloy that is placed under the heating process may transform into one of three
different states, which may be a mechanical mixture, a solid solution, or a
combination of the two.
Holding: Heat preservation or holding, alternatively, is the process where the
metal is maintained at an achieved or preferred temperature. During the holding
time, the surface temperature of a metal material is maintained for a certain
time so that its internal and external temperatures would become consistent.
Likewise, this specific step will allow the material to undergo microstructure
transformation. The duration of this process depends on the requirements, the
material type, and the part size of the material.
Cooling: Cooling is crucial for heat treatment processes as it determines the
outcome of the metal material. During the cooling process, the metal material
is expected to undergo structural changes through the help of different cooling
media like brine, water, oil, or forced air. Brine is known for its ability to
absorb heat the fastest, while air is known as the slowest among the mentioned
cooling media. The cooling requirements of metal materials would still depend,
however, on their specific type and composition.
The effects of heat treatment processes may vary
according to the composition of the metal and its overall condition. Steps and
elements involved in a specific heat treatment process can also affect the
outcome of a metal being processed and treated.
