Machining of NiHard Impellers

[arunmrao]

I have an enquiry for supply of NiHard impellers. Originally these were made in cast iron,hence machining posed no problems. Now due to wear problems the customer has requested in this wear resistant alloy having a hardness of RC55min.
The problem arises in the bore region where he has asked for a reverse taper bore along with a key and a blue contact of over 75% with the shaft.(No provision for using MS inserts as per the design).

Please advise if someone has the knowledge or experience in machining hard materials.

Thanks in anticipation.

 

[SteveKW]

Sounds more like he has the wrong pump for the application or is using it outside of its suggested parameters. Either of those two errors will "wear" the impeller just as quickly. A properly configured and sized pump & plumbing should take years to wear an impeller. Can you give details as to what kind of damage is being done?