Please use this identifier to cite or link to this item: https://scidar.kg.ac.rs/handle/123456789/20607
Title: Determination of the optimal tempering temperature in hard facing of the forging dies
Authors: Milan Mutavdzic
Lazic, Vukic
Milosavljevic, Dragan
Aleksandrovic, Srbislav
Nikolic, Ruzica
Rajko, Čukic
Bogdanovic, Gordana
Issue Date: 2012
Abstract: Here is analyzed selection of the optimal technology for heat treatment during the reparation of the damaged forging dies. Those tools are manufactured from alloyed tool steels for operation at elevated temperatures. Those steels are prone to self-hardening, so in reparatory hard-facing they must be preheated, additionally heated and tempered. During the tempering, in temperature interval 500-600°C, a secondary increase of hardness and decrease of impact toughness occurs, the so-called reversible tempering brittleness. Here is shown that it can be avoided by application of metallurgical and technological measures. Metallurgical measures assume adequate selection of steels. Since the considered steels are per se prone to tempering brittleness, we conducted experimental investigations to define the technological measures to avoid it. Tests on models were conducted: tempering from different temperatures, slow heating and cooling in still air. Hardness measurements showed that at 520°C, the secondary increase of hardness occurs, with drop of the impact toughness. Additional hard-facing tests included samples tempered at various regimes. Samples were prepared for mechanical and metallographic investigations. Results presented illustrate influence of additional heat treatment on structure, hardness and mechanical properties of the hard-faced layers. This enabled establishing the possibility of avoiding the tempering brittleness through technological measures
URI: https://scidar.kg.ac.rs/handle/123456789/20607
Type: article
ISSN: 1335-0803
Appears in Collections:Faculty of Engineering, Kragujevac

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