The influence of the tempering temperature on hydrogen embrittlement in carbonitrided modified SAE 10B22 steel

Abstract

The modified SAE 10B22 steel has high hardenability, which provides its use in special engineering applications, such as in self-drilling screws, with carbonitrided layer, quenched and tempered. However, these components are susceptible to hydrogen embrittlement, which can cause damage to structural components. In addition, the study of the behavior regarding to hydrogen embrittlement of components with carbonitrided layer has not been done hitherto. In this work the tempering temperature influence on hydrogen embrittlement of modified SAE 10B22 steel, was evaluated after a carbonitriding process. Standard samples and M4 Â 50 screws were tested. A galvanostatic circuit was used for hydrogen charging of the samples, which were characterized by low-strain tensile test and the samples fracture were analyzed by SEM. The obtained results demonstrate that by lowering tempering temperatures, the hydrogen-loaded samples presented a greater loss of mechanical properties and greater changes of the micromechanics of fracture. In addition, the geometry of the screw was more prone to the deleterious effects of the hydrogen charging than the conventional specimens.

Effects of Hot Stamping and Tempering on Hydrogen Embrittlement of a Low-Carbon Boron-Alloyed Steel

“…A number of experiments have been done regarding the effect of tempering treatment on the HE behavior of high strength martensitic steels, and it is regarded that the HE susceptibility of this type of steels could be lowered through the increase in tempering temperature on the condition that temper embrittlement is avoided [24,33,34,35,36,37,38]. This improvement was mainly correlated with microstructural evolution, including the decrease in dislocation density, the formation and morphology variation of carbides as well as the unavoidable strength loss for traditional low-alloy martensitic steels when the tempering temperature was high [24,34,36].…”

The influence of carbon potential after gas-carbonitriding on the microstructure and fatigue behavior of low alloyed steel

“…The hard carbonitrides, nitrides and carbides layer formed at the surface ameliorates the fatigue strength [19,20]. The carbonitriding treatment results in the formation of hardness gradient and the distribution of the residual stresses with compressive stresses at the surface microstructure because of the variation of volume during the martensitic transformation [21,22]. The surface layer increased hardness and strength, together with the compressive stress caused by the interaction between the surface and the core, improve the surface properties and raise the resistance to fatigue [23,24].…”

Avaliação da efetividade do tratamento termoquímico de carbonitretação em engrenagens de motocicletas

“…A combinação de uma superfície endurecida com um núcleo dúctil é favorável para peças como engrenagens, pois o aumento da dureza superficial reduz o desgaste e com o núcleo dúctil é capaz de absorver os esforços durante operações cíclicas. Os tratamentos termoquímicos também são utilizados para aumentar a resistência à corrosão, à fadiga, devido ás tensões compressivas e à oxidação em elevadas temperaturas [4][5][6].…”