Influence of operating parameters on morphology of laser hardened surfaces

Conventional heat treatment of a component is performed in a furnace whereby the component is continuously heated to a high temperature and quenched to get a hardened material. The furnace heating and tempering process take several hours which is expensive over a long run and less flexible. Laser tr...

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Main Authors: Maharjan, Niroj, Zhou, Wei, Zhou, Yu, Wu, Naien
其他作者: Kaierle, Stefan
格式: Conference or Workshop Item
語言:English
出版: 2018
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在線閱讀:https://hdl.handle.net/10356/89705
http://hdl.handle.net/10220/47223
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機構: Nanyang Technological University
語言: English
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spelling sg-ntu-dr.10356-897052023-03-04T17:08:17Z Influence of operating parameters on morphology of laser hardened surfaces Maharjan, Niroj Zhou, Wei Zhou, Yu Wu, Naien Kaierle, Stefan Heinemann, Stefan W. School of Mechanical and Aerospace Engineering Proceedings of SPIE 10525, High-Power Laser Materials Processing: Applications, Diagnostics, and Systems VII A*STAR Advanced Remanufacturing and Technology Centre Precision Laser Solutions Pte Ltd Steel Heat Treatment DRNTU::Engineering::Mechanical engineering Conventional heat treatment of a component is performed in a furnace whereby the component is continuously heated to a high temperature and quenched to get a hardened material. The furnace heating and tempering process take several hours which is expensive over a long run and less flexible. Laser transformation hardening is an attractive heat treatment technology which can be used to enhance the surface properties of highly stressed components such as cams, gears, and bearings without altering its bulk properties. The highly intense laser beam rapidly heats up the irradiated surface above its austenitization temperature which cools down instantaneously (self-quenching) as the laser moves away from the spot producing a hardened surface. The fast heating and cooling generate a non-equilibrium phase transformation of which very little is understood. An attempt was made to improve the surface properties of steel through solid solution hardening and microstructure refinement using a 250 W fiber laser. To identify the effect of various parameters on laser hardening, scanning conditions such as beam spot size, scan rate, power input, surface condition and overlap ratio were controlled. The change in hardness and morphology of laser treated surface were carefully investigated. The results show the surface hardness increased above 800 HV after laser treatment compared to 260 HV of the as-received specimen. It is found that austenitization has the highest effect on hardness achieved and can be controlled by proper choice of laser parameters and scanning rates. ASTAR (Agency for Sci., Tech. and Research, S’pore) Published version 2018-12-26T08:47:55Z 2019-12-06T17:31:37Z 2018-12-26T08:47:55Z 2019-12-06T17:31:37Z 2018 Conference Paper Maharjan, N., Zhou, W., Zhou, Y., & Wu, N. (2018). Influence of operating parameters on morphology of laser hardened surfaces. High-Power Laser Materials Processing: Applications, Diagnostics, and Systems VII. doi:10.1117/12.2288890 https://hdl.handle.net/10356/89705 http://hdl.handle.net/10220/47223 10.1117/12.2288890 en © 2018 Society of Photo-optical Instrumentation Engineers (SPIE). This paper was published in High-Power Laser Materials Processing: Applications, Diagnostics, and Systems VII and is made available with permission of Society of Photo-optical Instrumentation Engineers (SPIE). The published version is available at: [http://dx.doi.org/10.1117/12.2288890]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law. 11 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Steel
Heat Treatment
DRNTU::Engineering::Mechanical engineering
spellingShingle Steel
Heat Treatment
DRNTU::Engineering::Mechanical engineering
Maharjan, Niroj
Zhou, Wei
Zhou, Yu
Wu, Naien
Influence of operating parameters on morphology of laser hardened surfaces
description Conventional heat treatment of a component is performed in a furnace whereby the component is continuously heated to a high temperature and quenched to get a hardened material. The furnace heating and tempering process take several hours which is expensive over a long run and less flexible. Laser transformation hardening is an attractive heat treatment technology which can be used to enhance the surface properties of highly stressed components such as cams, gears, and bearings without altering its bulk properties. The highly intense laser beam rapidly heats up the irradiated surface above its austenitization temperature which cools down instantaneously (self-quenching) as the laser moves away from the spot producing a hardened surface. The fast heating and cooling generate a non-equilibrium phase transformation of which very little is understood. An attempt was made to improve the surface properties of steel through solid solution hardening and microstructure refinement using a 250 W fiber laser. To identify the effect of various parameters on laser hardening, scanning conditions such as beam spot size, scan rate, power input, surface condition and overlap ratio were controlled. The change in hardness and morphology of laser treated surface were carefully investigated. The results show the surface hardness increased above 800 HV after laser treatment compared to 260 HV of the as-received specimen. It is found that austenitization has the highest effect on hardness achieved and can be controlled by proper choice of laser parameters and scanning rates.
author2 Kaierle, Stefan
author_facet Kaierle, Stefan
Maharjan, Niroj
Zhou, Wei
Zhou, Yu
Wu, Naien
format Conference or Workshop Item
author Maharjan, Niroj
Zhou, Wei
Zhou, Yu
Wu, Naien
author_sort Maharjan, Niroj
title Influence of operating parameters on morphology of laser hardened surfaces
title_short Influence of operating parameters on morphology of laser hardened surfaces
title_full Influence of operating parameters on morphology of laser hardened surfaces
title_fullStr Influence of operating parameters on morphology of laser hardened surfaces
title_full_unstemmed Influence of operating parameters on morphology of laser hardened surfaces
title_sort influence of operating parameters on morphology of laser hardened surfaces
publishDate 2018
url https://hdl.handle.net/10356/89705
http://hdl.handle.net/10220/47223
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