A fast fracture approach to assess hydrogen embrittlement (HE) susceptibility and mechanism(s) of high strength martensitic steels

Assessment of Hydrogen Embrittlement Susceptibility and Mechanism(s) in Quench and Tempered AISI 4135 Steel Using A Novel Fast Fracture Test in Bending

“…The presence of a higher dislocation density and brittle transition carbides in the microstructure reduces the ability of Steel 4 to deform plastically by suppressing dislocation emission from notch tip and dislocation motion in the structure, respectively. Moreover, the dislocation generation during plastic deformation in Steel 1 also could play an important role in trapping H in the near notch root area as was explained in literature [7]. The significant difference in susceptibility among the materials can be explained with the help of a qualitative description based on linear elastic fracture mechanics (LEFM) for which further theoretical framework can be developed in future, to extended its capability for prediction purposes and understanding.…”

“…For this reason, an AISI 4135 steel, quench and tempered to four different strength (or hardness) levels was selected for the current study. The role of strength, plasticity and toughness affecting HE susceptibility of Q and T steels was studied and published by the authors in their previous paper where two different strength levels among the Q and T steels were compared [7]. The current research thus provides an opportunity to develop further understanding on the role of strength (in particular) affecting HE susceptibility over a wide range of hardness (or strength) levels in Q and T steels.…”

“…This test method involves cathodic pre-charging of H followed by a four-point bend test under continuous loading, which remarkably reduces the total test time as compared to the ISL test. The advantages of this HE test method were earlier discussed in detail in the preceding paper [7], where it was successfully applied to measure the fracture susceptibilities of three different high strength Q and T steels having different steel chemistries and strength levels. Here, it is noteworthy that the fast fracture test provides a straightforward, time efficient and standard evaluation based on similar level exposure to H concentration.…”

Enhancing the SCC Resistance of the Anchor Steel with Microalloying in a Simulated Mine Environment

“…According to reported statistics [1,2], 29% of anchor bolts and 25% of anchor cables in the Australian mining industries are subjected to corrosion failures, and corrosion has been recognized as one of the biggest threats to the life of anchor bolt structures buried in rock and soil layers. In addition, at external load or residual stress, stress corrosion cracking (SCC) and hydrogen embrittlement (HE) happen frequently and lead to abrupt failures [3][4][5]. Therefore, SCC and HE problems pose a serious threat to the safe service of anchor bolt structures and severely affect the development and application of anchor steels.…”