What's this phenomenon ?

[limct]

I have a carburised and ground 12L14 shaft with 730+/-50 HV Eht approx. 0.15, mating with a needle bearing. after the test cycle (rotation at 2600 rpm and 1.2mm axial reciprocating at 10cycle/rpm along the 8mm guiding span), there is a worn out marking on the shaft that is of yellowish colour, or to be more exact, looks like bronze colour. What's the explanation to this phenomenon?

Best regards,
ct

 

[Carburize]

Oxidized lubricant?

 

[Ron]

Burnt lubricant

 

[vcz]

Sounds like fretting corrosion. Normally caused by high contact stresses with slight relative movements on materials that readily oxidize. More length of contact may reduce stress, more lubricant may reduce oxidation.
Good luck.

 

[Carburize]

I don't think it is fretting corrosion unless limct decribed the color incorrectly - the debris from fretting is usually much more of a red color than the bronze described.

 

[SMF1964]

heat tinting from contact/friction?

 

[limct]

Hi SMF1964,
Thanks for the feedback, I'm new to this term, could you describe more?

Best regards,
ct