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|  MIL-P-17639F(SH)
be made by a minimum of two passes. The filler weld material shall be as
follows: Covered electrode in accordance with MIL-E-22200/3 (MIL-1N12),
or bare wire in accordance with MIL-E-21562 (MIL-EN625). Machining into
the first (lower) layer for the final surface shall not be permitted. The
final machined surface of the cladding shall be PT inspected. The accept-
ance standard shall be class I of NAVSEA 0900-LP-003-8000. The surrounding
areas shall be inspected in accordance with MIL-STD-278.
Sleeves that are subject to wear or that establish a critical clearance (that
is, less than 40 roils radial clearance) shall be made of nickel-copper-
aluminum alloy and shall meet the 265 Bhn specified in the table. Sleeves
for which footnote 8 requires weld cladding shall be made of nickel-copper
alloy. Other sleeves shall be made of either: (a) nickel-copper-aluminum
alloy meeting the annealing requirement of footnote 7 rather than the
above hardness requirement or, (b) nickel-copper alloy.
Special high lead bronze or other suitable bearing materials may be used
subject to review by the design agency. Bearing metal, alloy B-10, is an
acceptable alternative material.
When the mechanical properties of the material used in the fabrication of
a part are altered by metal working processes or heat treatment, sample
material from each lot of material, as defined in the material specification,
shall be subjected to tensile tests in the final heat treated condition for
the part. As a minimum, tensile tests shall determine ultimate strength,
yield strength, percent reduction in area, percent elongation and hardness.
The tensile tests shall be conducted on test samples machined from the heat
treated material or from a piece of parent stock which had been heat treated
in the same batch in the lot processed at the same time. The tensile test
requirements and acceptance criteria for mechanical properties shall be
included on the part drawing. Acceptance criteria for the mechanical
properties shall be in accordance with the material specification or as
approved by the design review agency. In no case shall ductility of less
than 10 percent elongation in 2 inches be allowed.
Where nickel-aluminum-bronze is used, it shall be in accordance with alloy
632M of QQ-C-465 and its amendment.
Cyclone separator parts exposed to water velocities greater than 15 feet per
second shall be made of nickel-copper alloy. Other cyclone separator parts
shall be 70-30 copper-nickel except: (a) parts such as fittings, not
readily available in 70-30 copper-nickel, may be made of nickel-copper alloy
and (b) parts that would be unacceptably galvanically attacked if made of
70-30 copper-nickel shall be made of nickel-copper alloy.
14/ These materials shall be furnished for all pumps furnished with corrosion-
resisting steel (ASTM A 744, grade CN-7M or CN-7MS) casings:
ASTM A 744 grade CN-7M
Highly-alloyed corrosion
Casing, impeller, and
or CN-7MS
resisting steel
throat bushing
ASTM B 446 , UNS N06625
Casing wearing ring
Ni-Cr-Mo-Cb alloy
ASTM B 446 , UNS N06625
Ni-Cr-Mo-Cb alloy
Shaft sleeves
A wearing ring and its opposing surface shall be of dissimilar material or
shall have a difference in hardness of at least 50 Bhn.
For vertical close-coupled pumps, where the entire weight Of the assembled
unit is supported by the mounting bracket, steel may be used for the
material of the bracket provided it does not form a part of the pump casing
and adequate provision is made for draining all pockets.
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