Citation

Lin S, Han X, Li G, Wang P, Zhao C, Yang Z. China Saf. Sci. J. 2022; 32(6): 115-122.

Copyright

(Copyright © 2022, China Occupational Safety and Health Association, Publisher Gai Xue bao)

DOI

10.16265/j.cnki.issn1003-3033.2022.06.2061

PMID

unavailable

Abstract

In order to improve service safety of high-speed trains and explore stress corrosion cracking fracture mechanism of welded joints, microstructure, mechanical properties, and stress corrosion cracking properties of MIG welding joints of 6005A aluminum alloy were investigated by adopting optical microscopy, transmission electron microscope (TEM), scanning electron microscope (SEM), hardness test, tensile test, constant stress corrosion load test and so on. The results show that under the effect of welding heat, intragranular precipitates is coarsened and redissolved in heat affected zone (HAZ), and precipitation free zone (PFZ) is widened at grain boundary. Hardness distribution of the joints is ＂ W＂ type, with minimal-hardness point located in HAZ zone, and MIG joints also fracture at HAZ zone in room temperature tensile test and constant load stress corrosion test. Along with the increase of loading stress, stress corrosion cracking sensitivity will increase, and intergranular stress corrosion cracking failure fracture will accelerate. And average fracture time of the joints reaches about 42 h under high load stress (0. 9 Ｒｐ0. 2). © 2022 China Safety Science Journal. All rights reserved.

Language: zh