Generally, the surface after heat treatment is done forms an oxide film (scale) and it needs to be removed by grinding after the process. Also, the carbon on the surface may be decarbonized. For this reason, the finished product will be applied with a gas that protects during heat treatment (heating). (If preventing from oxidization even more, then it should be treated in a vacuum.)

Metallographic structure and treatment condition

Quenching
Before treatment	Tensile strength that is high in martensite and is hard and brittle

Tempering
Sorbite Appropriate tensile strength and viscosity

Equipment

Batch type gas carbonization furnace

The factroy is able to do

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	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
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	Kariya Factory 46-1 Shimonagare, Ichiriyama-cho, Kariya-shi, Aichi-ken, 448-0002, Japan Tel. +81-(0)566-35-0361 Fax. +81-(0)566-35-0362