Title: High-frequency isothermic quenching of ductile iron
Application Number: 86107204 Application Date: 1986.10.15
Publication Number: 1018109 Publication Date: 1988.05.04
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: C21D5/00
Applicant(s) Name: Research Institute of Casting, Electro-machinery A Address:
Inventor(s) Name: He Ning
Attorney & Agent:
Abstract:
     The present invention provides a new method for heat treatment of ductile iron and the corresponding material. The ductile iron is obtained by means of high-frequency heating and isothermic quenching and its surface is of bainite structure, the remainding part is of monomeric unit of ferite or of mixed unit of pearlitic ferrite. As the surface organization is of bainitic structure, it has a higher tenacity and less trend in cracking than martenite. Since the ductile iron is heated only on the surface, the energy consumption is lower and the productive cycle is shortened. Since the interior is not to be hardened, its central part will be easier to be processed and has better performance of noice reducing than that with the ordinary isothermic quenching. Therefore, this material is supposed to be suitable for making machine elements which are only subjected to contacting load on their surfaces from the performance and economy point of view.
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