Formation of white etching areas in SAE 52100 bearing steel under rolling contact fatigue – Influence of diffusible hydrogen

Modeling hydrogen diffusion in a tribological scenario: A failure analysis of a thrust bearing

“…This information is also dependent on the increment of the serial sectioning procedure, which was about 300 µm in this work. A coarse cross sectioning results in a considerable margin of error for threedimensional crack networks; the three-dimensional nature of WEC/WEA is shown in the work of Oezel et al [58]. The density and distribution of WEC observed in the damaged rollers agree to a certain extent with the findings of Richardson et al [62].…”

“…For instance, the hydrogen content following the 25 h RCF tests (see Figure 9) is believed not to have reached a critical value to cause enough degradation/embrittlement in steel and enable crack initiation, thus, explains the absence of WEC/WEA in these tests. It was argued by several researchers that 1-2 ppm [58,59], or even slightly lower [60,61], of diffusible hydrogen content resulted in premature failure of bearing steel.…”

The multiple roles of a chemical tribofilm in hydrogen uptake from lubricated rubbing contacts

“…The accumulation of hydrogen beyond its solubility limit in these areas leads to the embrittlement of the steel. Hydrogen is also recognised as an influence on accelerating fatigue failure of tribological components by promoting White Etching Areas (WEAs), which are correlated to brittle flaking [1][2][3]. Studies on the detrimental effect of hydrogen showed an inverse relation between hydrogen content in steel and fatigue life of AISI 52100 bearing steel [4].…”

Accelerated White Etch Cracking (WEC) FE8 type tests of different bearing steels using ceramic rollers

“…There are still disagreements on the WEC failure mechanism in the literature and the root causes are still being researched [13][14][15][16][17]. For example, some sources indicate that the hard white nanostructure causes the cracks [18,19] while others indicate crack rubbing causes the hard white nanostructure [20,21]. Some preventive measures have been implemented by bearing, gearbox and wind turbine manufacturers, typically using new bearing types or bearing configurations based on best practice.…”