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Advanced Complex Analysis of the Thermal Softening of Nitrided Layers in Tools during Hot Die Forging

This article is devoted to the issues of thermal softening of materials in the surface layer of forging tools. The research covers numerical modeling of the forging process, laboratory tests of tempering of nitrided layers, and the analysis of tempering of the surface layer of tools in the actual fo...

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Autores principales: Krawczyk, Jakub, Widomski, Paweł, Kaszuba, Marcin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7828371/
https://www.ncbi.nlm.nih.gov/pubmed/33450920
http://dx.doi.org/10.3390/ma14020355
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author Krawczyk, Jakub
Widomski, Paweł
Kaszuba, Marcin
author_facet Krawczyk, Jakub
Widomski, Paweł
Kaszuba, Marcin
author_sort Krawczyk, Jakub
collection PubMed
description This article is devoted to the issues of thermal softening of materials in the surface layer of forging tools. The research covers numerical modeling of the forging process, laboratory tests of tempering of nitrided layers, and the analysis of tempering of the surface layer of tools in the actual forging process. Numerical modeling was supported by measuring the temperature inside the tools with a thermocouple inserted into the tool to measure the temperature as close to the surface as possible. The modeling results confirmed the possibility of tempering the die material. The results of laboratory tests made it possible to determine the influence of temperature on tempering at different surface layer depths. Numerical analysis and measurement of surface layer microhardness of tools revealed the destructive effect of temperature during forging on the tempering of the nitrided layer and on the material layers located deeper below the nitrided layer. The results have shown that in the hot forging processes carried out in accordance with the adopted technology, the surface layer of working tools is overheated locally to a temperature above 600 °C and tempering occurs. Moreover, overheating effects are visible, because the surface layer is tempered to a depth of 0.3 mm. Finally, such tempering processes lead to a decrease in the die hardness, which causes accelerated wear because of the abrasion and plastic deformation. The nitriding does not protect against the tempering phenomenon, but only delays the material softening process, because tempering occurs in the nitrided layer and in the layers deeper under the nitrided layer. Below the nitrided layer, tempering occurs relatively quickly and a soft layer is formed with a hardness below 400 HV.
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spelling pubmed-78283712021-01-25 Advanced Complex Analysis of the Thermal Softening of Nitrided Layers in Tools during Hot Die Forging Krawczyk, Jakub Widomski, Paweł Kaszuba, Marcin Materials (Basel) Article This article is devoted to the issues of thermal softening of materials in the surface layer of forging tools. The research covers numerical modeling of the forging process, laboratory tests of tempering of nitrided layers, and the analysis of tempering of the surface layer of tools in the actual forging process. Numerical modeling was supported by measuring the temperature inside the tools with a thermocouple inserted into the tool to measure the temperature as close to the surface as possible. The modeling results confirmed the possibility of tempering the die material. The results of laboratory tests made it possible to determine the influence of temperature on tempering at different surface layer depths. Numerical analysis and measurement of surface layer microhardness of tools revealed the destructive effect of temperature during forging on the tempering of the nitrided layer and on the material layers located deeper below the nitrided layer. The results have shown that in the hot forging processes carried out in accordance with the adopted technology, the surface layer of working tools is overheated locally to a temperature above 600 °C and tempering occurs. Moreover, overheating effects are visible, because the surface layer is tempered to a depth of 0.3 mm. Finally, such tempering processes lead to a decrease in the die hardness, which causes accelerated wear because of the abrasion and plastic deformation. The nitriding does not protect against the tempering phenomenon, but only delays the material softening process, because tempering occurs in the nitrided layer and in the layers deeper under the nitrided layer. Below the nitrided layer, tempering occurs relatively quickly and a soft layer is formed with a hardness below 400 HV. MDPI 2021-01-13 /pmc/articles/PMC7828371/ /pubmed/33450920 http://dx.doi.org/10.3390/ma14020355 Text en © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Krawczyk, Jakub
Widomski, Paweł
Kaszuba, Marcin
Advanced Complex Analysis of the Thermal Softening of Nitrided Layers in Tools during Hot Die Forging
title Advanced Complex Analysis of the Thermal Softening of Nitrided Layers in Tools during Hot Die Forging
title_full Advanced Complex Analysis of the Thermal Softening of Nitrided Layers in Tools during Hot Die Forging
title_fullStr Advanced Complex Analysis of the Thermal Softening of Nitrided Layers in Tools during Hot Die Forging
title_full_unstemmed Advanced Complex Analysis of the Thermal Softening of Nitrided Layers in Tools during Hot Die Forging
title_short Advanced Complex Analysis of the Thermal Softening of Nitrided Layers in Tools during Hot Die Forging
title_sort advanced complex analysis of the thermal softening of nitrided layers in tools during hot die forging
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7828371/
https://www.ncbi.nlm.nih.gov/pubmed/33450920
http://dx.doi.org/10.3390/ma14020355
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