Evaluation of Wear Resistance of AISI L6 and 5140 Steels after Surface Hardening with Boron and Copper

(1) Background: Boriding is one of the most common methods of thermal-chemical treatment due to its excellent hardness and wear resistance of the produced diffusion layers. However, it has limited application compared to carburizing and nitriding because of fragility and chipping. Introducing anothe...

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Main Authors: Stepan Lysykh, Vasily Kornopoltsev, Undrakh Mishigdorzhiyn, Yuri Kharaev, Zhongliang Xie
Format: Article
Language:English
Published: MDPI AG 2023-01-01
Series:Lubricants
Subjects:
Online Access:https://www.mdpi.com/2075-4442/11/2/48
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author Stepan Lysykh
Vasily Kornopoltsev
Undrakh Mishigdorzhiyn
Yuri Kharaev
Zhongliang Xie
author_facet Stepan Lysykh
Vasily Kornopoltsev
Undrakh Mishigdorzhiyn
Yuri Kharaev
Zhongliang Xie
author_sort Stepan Lysykh
collection DOAJ
description (1) Background: Boriding is one of the most common methods of thermal-chemical treatment due to its excellent hardness and wear resistance of the produced diffusion layers. However, it has limited application compared to carburizing and nitriding because of fragility and chipping. Introducing another alloying element into the boron media helps avoid those drawbacks and improve other surface properties of the layer. The purpose of this work is to improve the surface mechanical properties of L6 and 5140 low alloy steels by two-component surface hardening with boron and copper. (2) Methods: The treatment was performed by means of a powder-pack method using boron, copper, and aluminum powders in the following proportions: 60% B<sub>4</sub>C + 20% Al<sub>2</sub>O<sub>3</sub> + 16% CuO + 4% NaF. The time–temperature parameters of the treatment were four hours exposure at 950 °C. Microstructure, elemental, and phase composition were investigated as well as microhardness and wear resistance of the obtained layers. (3) Results: Layers of up to 180–200 μm thick are formed on both steels as a result of treatment. Needle-like structures similar to pure boriding was obtained. The maximum microhardness was 2000 HV on L6 steel and 1800 HV on 5140 steel. These values correspond to iron borides and were confirmed by XRD analysis revealing FeB, Fe<sub>2</sub>B, and Cr<sub>5</sub>B<sub>3</sub>. The wear resistance of both steels was about ten times higher after the treatment compared to non-treated samples. (4) Conclusions: Surface hardening with boron and copper significantly improves the mechanical properties of both alloy steels. The results obtained are beneficial for different tribo-pair systems or three-body wear with abrasion and minimum impact loads.
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spelling doaj.art-595df6eb488144a89c8757e155fe55132023-11-16T21:43:38ZengMDPI AGLubricants2075-44422023-01-011124810.3390/lubricants11020048Evaluation of Wear Resistance of AISI L6 and 5140 Steels after Surface Hardening with Boron and CopperStepan Lysykh0Vasily Kornopoltsev1Undrakh Mishigdorzhiyn2Yuri Kharaev3Zhongliang Xie4Institute of Physical Materials Science of the Siberian Branch of the Russian Academy of Sciences, 670047 Ulan-Ude, RussiaBaikal Institute of Nature Management of the Siberian Branch of the Russian Academy of Sciences, 670047 Ulan-Ude, RussiaInstitute of Physical Materials Science of the Siberian Branch of the Russian Academy of Sciences, 670047 Ulan-Ude, RussiaElectrical Engineering Faculty, East Siberia State University of Technology and Management, 670013 Ulan-Ude, RussiaDepartment of Engineering Mechanics, Northwestern Polytechnical University, Xi’an 710060, China(1) Background: Boriding is one of the most common methods of thermal-chemical treatment due to its excellent hardness and wear resistance of the produced diffusion layers. However, it has limited application compared to carburizing and nitriding because of fragility and chipping. Introducing another alloying element into the boron media helps avoid those drawbacks and improve other surface properties of the layer. The purpose of this work is to improve the surface mechanical properties of L6 and 5140 low alloy steels by two-component surface hardening with boron and copper. (2) Methods: The treatment was performed by means of a powder-pack method using boron, copper, and aluminum powders in the following proportions: 60% B<sub>4</sub>C + 20% Al<sub>2</sub>O<sub>3</sub> + 16% CuO + 4% NaF. The time–temperature parameters of the treatment were four hours exposure at 950 °C. Microstructure, elemental, and phase composition were investigated as well as microhardness and wear resistance of the obtained layers. (3) Results: Layers of up to 180–200 μm thick are formed on both steels as a result of treatment. Needle-like structures similar to pure boriding was obtained. The maximum microhardness was 2000 HV on L6 steel and 1800 HV on 5140 steel. These values correspond to iron borides and were confirmed by XRD analysis revealing FeB, Fe<sub>2</sub>B, and Cr<sub>5</sub>B<sub>3</sub>. The wear resistance of both steels was about ten times higher after the treatment compared to non-treated samples. (4) Conclusions: Surface hardening with boron and copper significantly improves the mechanical properties of both alloy steels. The results obtained are beneficial for different tribo-pair systems or three-body wear with abrasion and minimum impact loads.https://www.mdpi.com/2075-4442/11/2/48surface hardeningboridingiron boridescoppermicrohardnessmicrostructure
spellingShingle Stepan Lysykh
Vasily Kornopoltsev
Undrakh Mishigdorzhiyn
Yuri Kharaev
Zhongliang Xie
Evaluation of Wear Resistance of AISI L6 and 5140 Steels after Surface Hardening with Boron and Copper
Lubricants
surface hardening
boriding
iron borides
copper
microhardness
microstructure
title Evaluation of Wear Resistance of AISI L6 and 5140 Steels after Surface Hardening with Boron and Copper
title_full Evaluation of Wear Resistance of AISI L6 and 5140 Steels after Surface Hardening with Boron and Copper
title_fullStr Evaluation of Wear Resistance of AISI L6 and 5140 Steels after Surface Hardening with Boron and Copper
title_full_unstemmed Evaluation of Wear Resistance of AISI L6 and 5140 Steels after Surface Hardening with Boron and Copper
title_short Evaluation of Wear Resistance of AISI L6 and 5140 Steels after Surface Hardening with Boron and Copper
title_sort evaluation of wear resistance of aisi l6 and 5140 steels after surface hardening with boron and copper
topic surface hardening
boriding
iron borides
copper
microhardness
microstructure
url https://www.mdpi.com/2075-4442/11/2/48
work_keys_str_mv AT stepanlysykh evaluationofwearresistanceofaisil6and5140steelsaftersurfacehardeningwithboronandcopper
AT vasilykornopoltsev evaluationofwearresistanceofaisil6and5140steelsaftersurfacehardeningwithboronandcopper
AT undrakhmishigdorzhiyn evaluationofwearresistanceofaisil6and5140steelsaftersurfacehardeningwithboronandcopper
AT yurikharaev evaluationofwearresistanceofaisil6and5140steelsaftersurfacehardeningwithboronandcopper
AT zhongliangxie evaluationofwearresistanceofaisil6and5140steelsaftersurfacehardeningwithboronandcopper