Ask the Expert Question-and-Answer Archive
(Hard Chrome Plating)
by Larry Zitko, ChromeTech, Inc.
Wear Sleeve Packing
Q. We have a customer with a pump that is pumping sewage. At present the
packing wear sleeve is 416 ss. We would like to offer a modified sleeve
that would give a longer life cycle. Packing sleeve o.d. 2.437," speed is 1800
rpm and the pump runs 24/7. It is run at 450 hp, pumping 1980 usgpm at 312 psi. The sleeve has
6 rings of 3/8 " packing with lantern ring in middle. We would like to stay
with 416 ss as a base material due to ease of machining and corrosion
properties. Please advise if hard chrome is a viable option and what kind of
thickness , hardness, and life cycle can be expected. Thank you.
A. Hard chrome is plated on 416SS substrates all the time. Also, many pumps for
sludge, mud or sewage are chrome plated to extend their service life.
Chromium has very good wear properties, a low coefficient of friction and
excellent chemical resistance to most materials, so it's a good choice for
most pumping applications.
I once designed and installed a hard chromium plating line for a
manufacturer of this type of positive-displacement pump. We plated the
rotors with good success.
I am not able to predict life cycles, but they should be much longer than