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Wear of hard chrome against hard chrome

adv.    

I sell master gage rings and plugs. I have a situation where a customer wants to to qualify a high volume of chrome plated components with tolerances of 0.0001" to 0.0002" by inserting them into close tolerance chrome plated master ring gages - having tolerances of ±0.000005" (Class XXX)up to ± 0.000020" (Class X). Obviously, both the master rings and the components to be qualified are chrome plated for wear purposes. Both the parts and the master gages will have been ground or honed to a very fine finish, so the nodular characteristic of the chrome will have been "broken".

My question is:

"From your experience, do you have any feeling for how well the chrome wear parts (in this case the master rings) will hold up?"

Reason for the question: While chrome has a natural "lubricity", that benefit might not extend to a chrome against chrome condition. If the customer can expect excessive wear on the master rings I want to be able to advise him of this before he makes a decision.

Thank you in advance for your response.

Donald Sherry
- Cleveland, Ohio
2003

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The following is not from personal experience but data from technical tables from experiments in electroless plating with particles. Test was pin-on-plate rotary, 70 Kg load, dry. 1) Chrome vs. chrome: 6.72 total weight loss milligram/1000 cycle 2) Mild Steel vs. chrome: 4.9 Strange as it could seem, cohesion (same two metals in contact) turned out to be more destructive than adhesion (different metals) no matter one of them is very soft. Best results were observed with EN + lubricant particles. Even plain EN vs. EN showed a much better 0.74 figure.

Guillermo Marrufo
Monterrey, NL, Mexico
2003

Don't run hard chrome on hard chrome. It fails in every case. Don't run needle rollers, same reason. Think of it as glass re impact.

Mark Gunn
- NSW, Australia
2003

adv.