It is one of the heat treatment methods to harden the surface of an object but not the whole object. This method uses high frequency induction hardening. It is efficient since the necessary portion is hardened, and it is good to minimize thermal deformation rather than quenching throughout. This method is applied widely to machinery parts and automobile parts.

Principle
We apply HF current to heating coil which put around a part as shown in the figure, and it causes eddy current on the surface of the part and is heated by electrical resistance.

Metallographic structure
Microstructure

Single shot induction hardening

We generally apply scanning HF induction hardening for a long workpiece. If the workpiece has portion of different diameters, heating and/or cooling will be excessive or insufficient.
Then we apply single shot HF induction hardening for the workpiece by optimizing the shape of the heating coil to the shape of the workpiece, it is possible to heat and cool the workpiece uniformly. It is also possible to minimize the deformation and to get the high strength because of disappearing the stripe pattern, so-called "barber's pole pattern." And we increase the production capacity by separating a heating unit and a cooling unit.

Video presentation of treatment

 

Submerged induction hardening

Apply the induction hardening in a liquid. This makes hardening the narrow internal diameter, thin wall parts and neighbouring areas of the hardened part possible which were said to be impossible because of the limitation on machines and difficulty of heating/cooling before. Plus, it can inhibit forming when hardening. We have records of hardening the inside diameter of a spline.

Comparison between submerged induction hardening and conventional induction hardening

Non-oxidation induction hardening

In general induction hardening, because the scale (oxide film) occurs on the surface, polishing will be done in a later process, non-oxidation induction hardening can connect to reduction of production costs by reducing the scale forming on the surface to make omitting the polishing process possible.

Stationary type induction hardening

It is a heat treatment process that involves not moving a heating coil or workpieces.

Video presentation of treatment

 

Vertical movement type induction hardening

Vertical induction hardening is applied for the workpieces like round bars, we move a Induction heating coil or workpieces in a longitudinal direction and harden the workpieces.

Horizontal movement type induction hardening

This is applied for products that are going to be hardened on the flat surface mainly and they will be hardened moving the Induction heating coil / product horizontally.

Video presentation of treatment

 

Full automatic induction hardening

For products that will be treated a large amount like car parts which are all processed automatically including removal of the product to a hardening machine.

Video presentation of treatment

Full automatic induction hardening
(Turntable type)

 

Full automatic induction hardening
(Robotic detachable type)

 

Related equipment

Stationary type induction hardening machine	Vertical movement type induction hardening machine	Horizontal movement type induction hardening machine
Full automatic induction hardening machine	Single shot induction hardening machine	Submerged induction hardening machine
Oil submerged induction hardening machine

The factroy is able to do

Nagato Co., Ltd. & Oozu Factory 3-6-24 Oozu, Minami-ku, Hiroshima-shi, 732-0802, Japan Tel. +81-(0)82-282-4361 Fax. +81-(0)82-282-4262	Kaita Factory 9-9 Tsukimi-machi, Kaita-cho, Aki-gun, Hiroshima-ken, 736-0034, Japan Tel. +81-(0)82-822-2957 Fax. +81-(0)82-822-7294
Numata Factory 2-23-1 ohzuka-nishi, , Asaminami-ku, Hiroshima-shi, 731-3167, Japan Tel. +81-(0)82-848-6021 Fax. +81-(0)82-848-6301	Shiwa Factory 190-1 Aza Fukasako, Kanmuri, Shiwa-cho, Higashi-Hiroshima-shi, 739-0265, Japan Tel. +81-(0)82-420-5511 Fax. +81-(0)82-420-5615
Tokai Factory 138 Kasuga, Takaoka-Shinmachi, Toyota-shi, Aichi-ken, 473-0921, Japan Tel. +81-(0)565-52-3631 Fax. +81-(0)565-53-4611	Hofu Factory 26-1 Shintukiji-cho, Hofu-shi, Yamaguchi-ken, 747-0824, Japan Tel. +81-(0)835-25-3737 Fax. +81-(0)835-25-8626
Nagato Heat Treatment (Wuxi) Co., Ltd. NO.5 7th Factory,NO.31 Tuanjie Middle Road, Xishan Economic Development Zone, Wuxi, Jiangsu Province, China Tel. +86-(0)510-8826-7273 Fax. +86-(0)510-8826-7223	Nagato Heat Treatment (Thailand) Co., Ltd. 7 /379 Moo 6, Tambol Mabyangporn, Amphur Pluakdaeng, Rayong, Thailand Tel. +66-(0)38-027-473 Fax. +66-(0)38-027-475

Induction hardening	Applicable equipment	Processing factory
Stationary type induction hardening	Stationary type induction hardening machine	○	○	○	○	○	○
Vertical movement type induction hardening	Vertical movement type induction hardening machine	○	○		○	○	○	○
Horizontal movement type induction hardening	Horizontal movement type induction hardening machine		○
Full automatic induction hardening	Full automatic induction hardening machine	○				○
Single shot induction hardening	Single shot induction hardening machine	○				○
Submerged quenching	Submerged induction hardening machine	○
Non-oxidation quenching	Oil submerged induction hardening machine	○