Influence of UIT on VHCF Performance of SMA490BW Steel Welded Joints

被引：2

作者：

He, Bo-Lin ^{[1
]}

Deng, Hai-Peng ^{[1
]}

Wei, Kang ^{[2
]}

机构：

[1] College of Material Science and Engineering, East China Jiaotong University, Nanchang,330013, China

[2] CRRC Nanjing Puzhen Co. Ltd., Nanjing,210031, China

来源：

Zhongguo Biaomian Gongcheng/China Surface Engineering | 2017年 / 30卷 / 04期

基金：

中国国家自然科学基金;

关键词：

Compressive stress - Railroads - Residual stresses - Stress concentration - Grain size and shape - Nanocrystals - Fatigue of materials - Grain refinement - Finite element method - Welding - Microstructure - Surface stress - Bogies (railroad rolling stock);

D O I：

10.11933/j.issn.1007-9289.20170307002

中图分类号：

学科分类号：

摘要：

The welded toe surface of SMA490BW steel used to making bogie frame was treated using ultrasonic impact treatment (UIT) technology. The effect of UIT on the very high cycle fatigue(VHCF) properties of the welded joints were investigated. The microstructure of treated layer, geometrical morphology of weld toe before and after UIT, and grain refinement were analyzed by means of metallographic microscope, SEM and TEM. The stress distribution of the welded joint was calculated using finite element software, and the residual stress of weld toe surface area before and after UIT were measured and analyzed using X-ray stress tester. Results show that under the condition of 5×106 cycles, the fatigue strength of treated and as-welded joint is 206 and 153 MPa, respectively. The fatigue strength is increased by 34.6%. Under the condition of 1×108 cycles, the fatigue strength of treated joint is 195 MPa, and the fatigue strength is increased by 38.3% compared to 141MPa of as-welded joint. Under the stress level of 240 MPa, the fatigue life of treated joint is enhanced to 7 times than that of as-welded. After UIT, the stress concentration factor of weld toe is decreased by 19.1%, and the residual tensile stress in the surface of the weld toe is eliminated, and it changes into the beneficial residual compressive stress, the surface microstructure is refined. The three aspects of stress concentration of the weld toe, residual stress distribution and surface grain refinement have played a positive contribution to improve the fatigue performance of welded joint. © 2017, Editorial Office of CHINA SURFACE ENGINEERING. All right reserved.

引用

页码：64 / 70