Effect of laser surface remelting on the fatigue crack propagation rate of 40Cr steel

In the present work, quenched and tempered 40Cr steel was treated by laser surface remelting, followed by microstructure evolution, hardness, residual stress field and external morphology investigation to understand the effect of laser surface remelting on surface characteristics, as well as the gra...

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Main Authors:	Xiaohui Zhao, Haichao Zhang, Yu Liu
Format:	Article
Language:	English
Published:	Elsevier 2019-03-01
Series:	Results in Physics
Online Access:	http://www.sciencedirect.com/science/article/pii/S2211379718329097

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record_format	Article
spelling	doaj-c959edecfef943389af20698a77648c22020-11-24T21:43:38ZengElsevierResults in Physics2211-37972019-03-0112424431Effect of laser surface remelting on the fatigue crack propagation rate of 40Cr steelXiaohui Zhao0Haichao Zhang1Yu Liu2Key Laboratory of Automobile Materials, School of Materials Science and Engineering, Jilin University, Changchun 130025, China; Qingdao Automotive Research Institute of Jilin University, Loushan Road NO. 1, Qingdao 266000, ChinaKey Laboratory of Automobile Materials, School of Materials Science and Engineering, Jilin University, Changchun 130025, ChinaSchool of Mechanical and Aerospace Engineering, Jilin University, Changchun 130025, China; State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China; Corresponding author at: School of Mechanical and Aerospace Engineering, Jilin University, Changchun 130025, China.In the present work, quenched and tempered 40Cr steel was treated by laser surface remelting, followed by microstructure evolution, hardness, residual stress field and external morphology investigation to understand the effect of laser surface remelting on surface characteristics, as well as the grain refinement mechanism. Then, fatigue tests were carried out to obtain the fatigue crack growth rate and fracture morphology, thereby further discussing the fatigue crack propagation and fracture mechanism. Results indicate that the grain refinement mechanism of 40Cr steel treated by laser surface remelting can be attributed to the rapid melting-solidification process in surface, during which tempered sorbite is transformed into fine martensite. In addition, the residual compressive stress can be produced by the thermal effect. The fine microstructure and residual compressive stress lead to a significant decrease in crack propagation rate due to the high density of grain boundaries which hinder crack propagation. Keywords: Laser surface remelting, Microstructure, Hardness, Residual stress, Crack propagation ratehttp://www.sciencedirect.com/science/article/pii/S2211379718329097
collection	DOAJ
language	English
format	Article
sources	DOAJ
author	Xiaohui Zhao Haichao Zhang Yu Liu
spellingShingle	Xiaohui Zhao Haichao Zhang Yu Liu Effect of laser surface remelting on the fatigue crack propagation rate of 40Cr steel Results in Physics
author_facet	Xiaohui Zhao Haichao Zhang Yu Liu
author_sort	Xiaohui Zhao
title	Effect of laser surface remelting on the fatigue crack propagation rate of 40Cr steel
title_short	Effect of laser surface remelting on the fatigue crack propagation rate of 40Cr steel
title_full	Effect of laser surface remelting on the fatigue crack propagation rate of 40Cr steel
title_fullStr	Effect of laser surface remelting on the fatigue crack propagation rate of 40Cr steel
title_full_unstemmed	Effect of laser surface remelting on the fatigue crack propagation rate of 40Cr steel
title_sort	effect of laser surface remelting on the fatigue crack propagation rate of 40cr steel
publisher	Elsevier
series	Results in Physics
issn	2211-3797
publishDate	2019-03-01
description	In the present work, quenched and tempered 40Cr steel was treated by laser surface remelting, followed by microstructure evolution, hardness, residual stress field and external morphology investigation to understand the effect of laser surface remelting on surface characteristics, as well as the grain refinement mechanism. Then, fatigue tests were carried out to obtain the fatigue crack growth rate and fracture morphology, thereby further discussing the fatigue crack propagation and fracture mechanism. Results indicate that the grain refinement mechanism of 40Cr steel treated by laser surface remelting can be attributed to the rapid melting-solidification process in surface, during which tempered sorbite is transformed into fine martensite. In addition, the residual compressive stress can be produced by the thermal effect. The fine microstructure and residual compressive stress lead to a significant decrease in crack propagation rate due to the high density of grain boundaries which hinder crack propagation. Keywords: Laser surface remelting, Microstructure, Hardness, Residual stress, Crack propagation rate
url	http://www.sciencedirect.com/science/article/pii/S2211379718329097
work_keys_str_mv	AT xiaohuizhao effectoflasersurfaceremeltingonthefatiguecrackpropagationrateof40crsteel AT haichaozhang effectoflasersurfaceremeltingonthefatiguecrackpropagationrateof40crsteel AT yuliu effectoflasersurfaceremeltingonthefatiguecrackpropagationrateof40crsteel
_version_	1725912976782786560

Effect of laser surface remelting on the fatigue crack propagation rate of 40Cr steel

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