Effect of hydrogen on void initiation in tensile test of carbon steel JIS-S25C

2018 International Conference on Material Strength and Applied Mechanics

材料科学;力学

Sugawa, S.^1 ; Tsutsumi, N.^2 ; Oda, K.^2

Graduate School of Oita University, 700 Dannoharu, Oita

870-1192, Japan^1

Division of Mechanical Engineering, Oita University, 700 Dannoharu, Oita

870-1192, Japan^2

关键词: Charged specimens;    Dislocation densities;    Effect of hydrogen;    Fracture surfaces;    Hydrogen contents;    Reduction of areas;    Tensile fractures;    Void initiation;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/372/1/012008/pdf
DOI  :  10.1088/1757-899X/372/1/012008

来源: IOP

【 摘 要 】

In order to investigate the effect of hydrogen on tensile fracture mechanism of a carbon steel, tensile tests were conducted. Pre-strain specimens (0%, 5% and 10%) were used to study the effect of hydrogen content, since saturated hydrogen content in specimens increases in increasing dislocation density. The tensile strength and the yield stress of hydrogen specimens were almost the same as uncharged. In contrast, the reduction of area of hydrogen charged specimens was smaller than that of uncharged. To reveal the reasons of decrease of the reduction of area, the fracture surface and longitudinal cross section near the fracture surface were observed. On the fracture surface of uncharged specimens, only dimples were observed. On the other hand, dimples and flat fracture surface were observed on the fracture surface of hydrogen charged. On the longitudinal cross section of hydrogen charged specimens, many voids were observed compared to uncharged. From these observations, it is showed that hydrogen gives a rise to the increase of voids and the hydrogen charged specimens break without sufficient necking, thus hydrogen makes the reduction of area smaller.