<abstract xmlns="http://www.w3.org/1999/xhtml"><p>In heat-treating furnaces, many different types of protective atmospheres are used. This article researches the effect of protective atmospheres on the quality of the surface layer of bolts during the process of heating to reach the temperature of hardening. For this research, we produced specimens that were annealed in the furnace with two different types of protective atmosphere, i.e. in atmospheres of endothermic gas and nitrogen. After hardening and tempering, we measured the hardness of the specimens and investigated the microstructure. We measured the hardness profile from the surface to the inside of the product. We found that the hardness of the surface of the tested product was lower while using protective atmosphere of nitrogen due to the occurrence of ferrite. The depth of the decarburised layer in this atmosphere reached up to 70 mm, where predominantly there was a microstructure of ferrite on the surface, and then, with depth, an increasingly mixed microstructure of ferrite and martensite was found. The depth of the decarburised layer for sample treated in endothermic gas was minimal (i.e. 10 mm) on the surface.</p></abstract>

In heat-treating furnaces, many different types of protective atmospheres are used. This article researches the effect of protective atmospheres on the quality of the surface layer of bolts during the process of heating to reach the temperature of hardening. For this research, we produced specimens that were annealed in the furnace with two different types of protective atmosphere, i.e. in atmospheres of endothermic gas and nitrogen. After hardening and tempering, we measured the hardness of the specimens and investigated the microstructure. We measured the hardness profile from the surface to the inside of the product. We found that the hardness of the surface of the tested product was lower while using protective atmosphere of nitrogen due to the occurrence of ferrite. The depth of the decarburised layer in this atmosphere reached up to 70 mm, where predominantly there was a microstructure of ferrite on the surface, and then, with depth, an increasingly mixed microstructure of ferrite and martensite was found. The depth of the decarburised layer for sample treated in endothermic gas was minimal (i.e. 10 mm) on the surface.

The effect of protective atmosphere on decarburisation of the heat-treated surface of steel

marica.prijanovic-tonkovic@guest.arnes.si

Materials and Geoenvironment

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

In heat-treating furnaces, many different types of protective atmospheres are used. This article researches the effect of protective atmospheres on the quality...

The effect of protective atmosphere on decarburisation of the heat-treated surface of steel

Published Online: Apr 04, 2018

Page range: 199 - 204

Received: Aug 07, 2017

Accepted: Sep 25, 2017

DOI: https://doi.org/10.1515/rmzmag-2017-0019

Keywords
heat treatment, protective atmosphere, decarburisation, endothermic gas, nitrogen, microstructure

© 2017 Marica Prijanovič Tonkovič et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

The effect of protective atmosphere on decarburisation of the heat-treated surface of steel

Published Online: Apr 04, 2018

Page range: 199 - 204

Received: Aug 07, 2017

Accepted: Sep 25, 2017

DOI: https://doi.org/10.1515/rmzmag-2017-0019

Keywordsheat treatment, protective atmosphere, decarburisation, endothermic gas, nitrogen, microstructure

© 2017 Marica Prijanovič Tonkovič et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
heat treatment, protective atmosphere, decarburisation, endothermic gas, nitrogen, microstructure