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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2014, Vol. 35 ›› Issue (10): 2873-2880.doi: 10.7527/S1000-6893.2014.0153

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Stress Corrosion Cracking Behavior of 23Co14Ni12Cr3Mo Ultra-high Strength Steel in 3.5% NaCl Solution by DCB Specimens

WEN Chen, YU Mei, LI Songmei, LIU Jianhua   

  1. School of Materials Science and Engineering, Beihang University, Beijing 100191, China
  • Received:2014-04-22 Revised:2014-07-08 Online:2014-10-25 Published:2014-07-18
  • Supported by:

    National Natural Science Foundation of China (51171011)

Abstract:

With high strength and toughness, 23Co14Ni12Cr3Mo ultra-high strength steel, instead of other ultra-high strength steels, is widely used in bearing components such as landing gears. It is of great significance for safe and reliable application of 23Co14Ni12Cr3Mo ultra-high strength by investigating its stress corrosion cracking (SCC) behavior. The bifurcation behavior in SCC propagation of ultra-high strength steel 23Co14Ni12Cr3Mo is investigated by using double cantilever beam (DCB) specimens in 3.5 % NaCl solution, which provides theoretical supports for the safety application of the material as landing gear. The SCC morphology is observed by using scanning electron microscopy (SEM) and the composition of corrosion products is analyzed by using X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). The results show that the corrosion crack propagates to bifurcations and the fracture morphology is transgranular (TG) brittle cracking at prophase of crack propagation, TG cracking along with intergranular (IG) cracking factors in some regions,especially some second cracks at metaphase, and TG and brittle cracking at anaphase. The corrosion products consist of Fe, Cr and Co oxides. Effects of the elements Co, Cr, Ni, and Mo on the crack propagation are discussed.

Key words: ultra-high strength steel, 23Co14Ni12Cr3Mo, SCC, crack propagation, bifurcation

CLC Number: