Enhanced Fatigue Property of Welded S355J2W Steel by Forming a Gradient Nanostructured Surface Layer

作     者：Lu An Yan-Tao Sun Shan-Ping Lu Zhen-Bo Wang Lu An;Yan-Tao Sun;Shan-Ping Lu;Zhen-Bo Wang

作者机构：Shenyang National Laboratory for Materials ScienceInstitute of Metal ResearchChinese Academy of SciencesShenyang 110016China 

出 版 物：《Acta Metallurgica Sinica(English Letters)》 (金属学报（英文版）)

年 卷 期：2020年第33卷第9期

页      面：1252-1258页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：the National Key Research and Development Program of China(Nos.2017YFA0204401 and 2017YFA0204403) the Liaoning Revitalization Talents Program(No.XLYC1808008) the Shenyang National Laboratory for Materials Science 

主　　题：Gradient nanostructured Surface mechanical rolling treatment S355J2W steel Welded Fatigue 

摘      要：Welded joints are usually characterized by microstructural and compositional inhomogeneities, which may significantly degrade their fatigue properties and result in unpredictable failures. The present work demonstrates a novel and simple method to effectively optimize the microstructure in the surface layer and promote the fatigue properties of welded specimens. By a recently developed approach—surface mechanical rolling treatment(SMRT), a gradient nanostructured surface layer is formed on welded S355 J2 W steel specimens. The mean grain size is refined to nanometer scale, and the hardness is significantly enhanced in the SMRT surface layer. Independent of the initially inhomogeneous microstructure and hardness distributions, the microstructure and hardness distributions in the surface layers are comparable on different zones of a welded specimen after SMRT with the same procedure. Consequently, fatigue property of the SMRT specimens is significantly enhanced relative to that of the as-welded specimens within the high cycle fatigue regime.