Lubrication fundamentals

A: A: This is the point of the standard. The grade is anchored at 40 °C, not where your machine lives, so you back‑calculate to keep film thickness where you need it. B: No such rpm rule exists in ISO 3448. That's a misremembered OEM guideline. C: Oxidation matters, but viscosity grading isn’t an oxidation control method. D: Boundary lubrication is exactly what you’re trying to avoid here.

A: A: Alkaline cleaners strip or neutralize EP additives, and that shows up first as surface fatigue. B: Hydrogen embrittlement doesn’t fit the steel grade or environment. C: There’s no electrolyte path or dissimilar couple doing the damage. D: Residues can be ugly, but they don’t explain micropitting this early.

A: A: Oscillation kills hydrodynamic wedges, so you lean on boundary protection. B: Circulating oil looks good on paper, but there’s no speed to build a film. C: Dry films wear off fast at these contact pressures. D: Oil mist won’t stay put once the load comes on.

A: A: Mixing thickeners is where field failures start, not at the bench. B: NLGI grade is consistency, not load rating. C: Polyurea works fine in many bearings when specified correctly. D: That temperature limit is a myth.