Resistance of Hydrogen Embrittlement on Hot-sheared Surface during Die-quench Process

Abstract

This study investigated the resistance of hydrogen embrittlement on a hot-sheared and quenched surface of 22MnB5 steel sheets. The specimens were sheared at 750°C and 650°C after austenitization, and then quenched by water cooling. Additionally, these specimens were cathodically hydrogenized for 48 h to accelerate cracking by hydrogen embrittlement. This sequence resulted in a residual tensile stress of over 1 GPa on the hot-sheared surface and a diffusible hydrogen density of about 1.5 ppm. Despite these severe conditions, cracking by hydrogen embrittlement did not arise. The state of the microstructure in the vicinity of the sheared surface might cause this high resistance against cracking. Indeed, sub-micron grained ferrite or deformed uncertain soft and hard phases, which might be more ductile than martensite, were observed around the sheared surface.

The influence of microstructure on the hydrogen embrittlement susceptibility of martensitic advanced high strength steels

“…He suggested that tempering above 200 o C is not recommended for MS-AHSS as this treatment leads to a significant loss in strength but without the expected improvement in ductility, toughness and bendability. Finally, Matsuno et al [53] observed that ductile phases like ferrite and bainite lessen the hydrogen sensitivity of hot-sheared quenched 22MnB5 steels.…”

“…It is likely that the presence of ferrite may have contributed to a reduction of the HE susceptibility of MS-AHSS. Matsuno et al [53] observed the ability of ductile phases (e.g. ferrite and bainite) to reduce the hydrogen sensitivity of martensitic sheet steels.…”

Effect of Surface Conditions and Relative Humidity on Hydrogen Permeation Behavior of Zinc Coated Steels during Wet and Dry Corrosion

“…Therefore, hydrogen embrittlement has attracted much attention recently. [6][7][8][9][10][11][12][13][14][15][16] Matano et al 8) reported an evaluation of deformation microstructures and associated lattice defects in SUS 304 and SUS 316 L steels by positron lifetime measurements detecting vacancy-type defects created during tensile straining. Nagao et al 10) investigated the mechanism of fracture surface morphology changes at intergranular and quasi-cleavage in a hydrogen embrittled lath martensitic steel.…”

Effect of Surface Conditions and Specimen Composition on Hydrogen Permeation Behavior of Coated and Uncoated Steels during Wet and Dry Corrosion at a Constant Dew Point

“…1,2) To ensure reliability and safety in the practical use of high strength steels, a reduction in the susceptibility to hydrogen embrittlement has become an important issue and hydrogen embrittlement has attracted much attention recently. [3][4][5][6][7][8][9][10][11][12][13] Koyama et al investigated the effect of hydrogen embrittlement of a Fe-18Mn-0.6C austenitic steel (wt.%) by tensile tests with hydrogen charging at various current densities. They reported that the work hardening behavior was not affected by the hydrogen charging.…”