OILING IDLER SYSTEM FOR GEAR LUBRICATION

[ibf]

Dear All :

Material - Aluminum - grade 6061 - T6.

Oprating temperature - 60 / 70 C.

Environment : vapors of sulfuric acid ; phosphoric acid and ammonia.

Application : N , P , K fertilizer dryer.

The surface texture presents a blue coloration on the bushing.

Questions:

1. Could the blue coloration be copper sulfate ?

2. Could the above conditions cause corrosion on that grade of aluminum ?

Thank you.

 

[kenvlach]

1. No, the little bit of Cu (0.4 wt% max) in Al 6061 will be present in the form of an intermetallic and is protected against corrosion by the Al matrix (anodic).

2. Yes, both sulfuric & phosphoric acids corrode Al alloys. Ammonia does not (except anhydrous, with < 0.1% H₂O).

Is Al 6061 the gear? What is the bushing material?

 

[ibf]

Thank you for the prompt reply kenvlach.

The blue coloration is on the aluminum bushing.