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 CASE ML3 - Galling of Sluice Gates, J. Cecilio
Galling of Sluice Gates
Problem:
Collection of Facts: It was reported that the trim for the sluice gate of
Drydock No. 3 at Pearl Harbor was experiencing severe galling. The new sluice
gate was trimmed with monel metal. Complete elimination of galling of the
seating surfaces is very difficult to achieve. A survey of Naval Shipyards
was performed for evaluating galling of sluice gate which is as follows:
a. San Diego Naval Shipyard: Sluice gates, manufactured by Armco are
cast iron with monel trim. Minor problems with galling.
b. Portsmouth Naval Shipyard: Sluice gates, manufactured by Rodney Hunt,
are cast iron with bronze trim. The gates on one dock have no trim with cast
iron seating surfaces. They have experienced no galling.
C. Long Beach Naval Shipyard: Sluice gate cast iron with bronze trim.
Some minor problems with galling. They repaired the trim on the gates of one
dock by spray metalizing with bronze and remachining.
d. Puget Sound Naval Shipyard: Sluice gates, manufactured by Rodney
Hunt, are cast iron gates and frames trimmed with monel on one dock. They
have one set of gates yard-manufactured. They have experienced minor problems
where the seating surfaces were of like material.
e. Norfolk Naval Shipyard: Sluice gates are cast iron trimmed as follows:
Dock #2-cast iron with CUNI trim ASTM B-122 alloy 715; Dock #4-cast iron with
phosphor bronze trim built by Armco-ASTM B-139 alloy 510; Dock #8-cast iron
with either monel or bronze. They have experienced no galling problem.
f. Mare Island Naval Shipyard: Sluice gates for two docks are cast iron
with the exception of those for Drydock #l which are stainless steel type 304
purchased in 1958. Some galling has been experienced. One cast iron gate is
trimmed with monel purchased in 1938. On this gate, some galling has been
experienced. The gates purchased in 1938 are trimmed in bronze. Galling has
been noted on this gate's matting surface.
Newport News Shipbuilding and Drydock Company: On their docks for
g.
carriers, they are using stainless steel trim. They are in the process of
replacing the other gates at this time.
Solution:
The following guidance was developed:
1. Like metals such as 400 monel to 400 monel may be successfully used
for trim when the unit pressure from the water head is low-below 2,000 psi.
The normal surface finish should be 63 micro inches or better.
2.
When pressure exceeds 2,000 psi, ARMCO used materials of differential
3.
hardness or dissimilar metal for the gate trim and the frame trim. As an
example, for high water head cover 2,000 psi it was common for one side of the
sealing surface to be made of 304 stainless steel while the other side was
made of Phosphor Bronze.
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