HYDROGEN EMBRITTLEMENT OF SPHEROIDIZED HIGH CARBON STEEL SHEET UNDER MULTIAXIAL STRESS STATE
FAN Yunchang; JIA NG Zhiqing (Shijiazhuang Railway institute;Shijiazhuang 050043)(Manuscript received 1995-03-30; in revised form 1995-05-29)
Cite this article:
FAN Yunchang; JIA NG Zhiqing (Shijiazhuang Railway institute;Shijiazhuang 050043)(Manuscript received 1995-03-30; in revised form 1995-05-29). HYDROGEN EMBRITTLEMENT OF SPHEROIDIZED HIGH CARBON STEEL SHEET UNDER MULTIAXIAL STRESS STATE. Acta Metall Sin, 1995, 31(10): 445-454.
Abstract The hydrogen embrittlement of a spheroidized high carbon steel sheet has been investigated over a range of stress states from uniaxial to equibiaxial tension. For a given stress state, data based on locally determined fracture strains show a decrease in ductility for cathodically charged specimens compared with the corresponding uncharged condition. The loss of ductility caused by hydrogen increases with an increasing degree of biaxiality of the stress state. Metallographic and fractographic examinations show that the fracture of both charged and uncharged sheets is a consequence of void nucleation (due to the decohesion between carbide particles and ferrite matrix),void growth,and void link─up. These fracture processes are accelerated by hydrogen,especially in equibiaxial tension. The above results are discussed in terms of previously proposed modles and postulated mechanisms in steels.Correspondent: FAN Yunchang, senior engineer, Institute of Materials Science and Engineering, Shijiazhuang Railway institute, Shijiazhuang 050043
