Report on Induction Tempering

Dimitry Ivanov, Harald Hanche-Olsen, Thomas Petzoldt, Ian Roper, Thomas Roy, Christian Veje

Research output: Book/reportReportResearch


The problem posed by the company EFD Induction deals with the process of induction tempering.
Tempering is part of the heat treatment for workpieces made of steel. During the hardening of the
steel, the phase martensite has formed, which has high hardness but is very brittle. In order to improve
the properties of the workpiece, tempering is performed, where the part is heated up again to a dened
temperature. During this additional heating, some of the internal stresses in the martensitic phase are
released. Regarding the microstructure of the steel, carbides are formed during the heating that lead to
a removement of the excess hardness and an overall improvement of the toughness of the steel.
Therefore, tempering results in an increase of ductility at the cost of a reduction of hardness. Based
on the desired properties of the nal product, the tempering process needs to be controlled to achieve
the required properties. The parameters to be controlled are the temperature and the heating time.
One way of tempering is to use a furnace, where the parts are heated at constant temperature for a
specied time duration. The usual heating times are in the range of one hour. On the other hand, the
tempering can be done using inductive heating. The advantage of induction tempering is that the heat
is generated directly in the part. As a consequence, the heating times are much shorter, usually in the
range of 10 to 30 seconds, see Fig. 1, which makes the process very energy ecient.
Original languageEnglish
Number of pages10
Publication statusPublished - 2018
EventESGI 137: Norwegian Study Group with Industry - Ålesund, Norway
Duration: 11. Jun 201815. Jun 2018
Conference number: 1


ConferenceESGI 137: Norwegian Study Group with Industry
Internet address

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