Induction hardening is a type of heat treatment in which metal
parts are heated by electromagnetic induction and then quenched. It
is also a type of case hardening and can be used for many steel and
steel alloys to improve mechanical properties such as surface
hardness and fatigue strength and resistance.Typical applications of induction hardening is the hardening of
steel and cast iron. Especially parts, such as drive shafts, engine
components and gears undergo the process.
INDUCTION HARDENING PROCESS
Induction Hardening can be split into two steps. The first one is
induction heating, in which electrically conducting metals are
heated with an electromagnet. The quenching phase follows directly
after to alter the surface structure of the material.
INDUCTION HEATING
Materials such as steel components are typically placed inside a
water cooled copper coil where they are subject to an alternating
magnetic field. They undergo electromagnetic induction by means of
an electromagnet and an electronic oscillator. This oscillator
sends alternating currents through the electromagnet, causing
alternating magnetic fields that penetrate the material. The
results are eddy currents (loops of electrical current) which heat
the object within the coil above the transformation temperature.
Induction hardening is a form of surface hardening in which the
depth can be up to 8 mm. The deeper the currents penetrate, the
higher the frequency of the alternating magnetic fields have to be.
Steels that have a ferromagnetic structure (which is inherited from the iron) can also
be heated by magnetic hysteresis losses. Magnetic hysteresis losses
produce heat by re-aligning magnetic domains, although it depends
on the frequency of the currents, the penetration depth and the
properties of the material (size, density, alloys) how much heat can be generated (Ph = (kh
)(f)(Bmax)n).
INDUCTION QUENCHING
Directly after the induction heating process, the object has to be
quenched, meaning that it has to be cooled down extremely quickly.
To do that, the workpiece is typically placed in a tank of oil or
water, although sometimes cold air is used. Quenching ensures that
only the surface is hardened and that heat doesn’t spread into the
core of the material, avoiding phase transformations from arising.
Furthermore, the rapid cooling down creates a martensitic or
ferritic-martensitic structure on the surface layer. These
structure display higher tensile strength and low initial yielding
stress than a purely ferritic structure. Quenching also reduced
grain size, which is a key factor to increasing hardness of
materials.
Quick Detail:
| Name | Spray cooling Quenching Machine Induction Hardening Machine For
Tempering Gear | Application | Quenching |
| Net weight | 900kg | Cooling method | immersion, hydrojet |
| Dimension | 1100*900*2000 | Certificate | CE,SGS |
Technical Parameters
- The maximum diameter of quenching material: 300mm
- The maximum weight of the work piece: 50kg
- Work piece operating speed:1-30mm/s
- Work piece descent speed: 120mm/s
- Speed of main shaft:1-200r/min
- Motor power of main drive: 1.5kw
- Cooling method: immersion, hydrojet
- Machine Weight: 900kg
- Dimension: 1100*900*2000
- Transmission mode: mechanical rotation
Advantages of induction hardening:
- Ability to localize hardening to specific areas.
- Less distortion than alternatives such as carburizing.
- Heavy case depths achievable, 1-10mm common.
- Cheap/economical especially with parts of mass >10Kg.
- Fast process - quick turnaround.
