2.1.3.4
Piston Rods (Standard Design)
The piston rod shall be made of [medium carbon steel with a yield strength
of 620 to 690 MPa 90,000 to 100,000 psi for rods 16 through 100 mm 5/8
through 4 inches in diameter][ 620 to 760 MPa 90,000 to 110,000 psi high
tensile strength steel using ASTM A 108, Type C 1045, for rods 16 to 63 mm
5/8 to 2 1/2 inches in diameter, and ASTM A 331, Type CR 4140, for rods 75
to 250 mm 3 to 10 inches in diameter]. [The rod shall be case hardened to
50-54 Rockwell C, polished to a 0.25 micrometer 10 microinch RMS surface
finish or better, and nickel and hard-chrome plated to 75 micrometer 0.003
inch minimum thickness.] [The rod shall be ceramic coated to 200 micrometer
0.008 inch minimum thickness with surface finish of 0.30 micrometers 12
microinches RMS or better, surface hardness of 67 Rockwell C minimum,
impact resistance of 7 to 15 N-m, 5 to 11 lb-ft, modulus of elasticity of
360 to 415 GPa 52 x 106 to 60 x 106 psi, linear expansion coefficient of
7.2 x 10-6/degree C, 4.0 x 10-6/degree F, and be capable of withstanding a
fracture force of 280 MPa 41 ksi minimum. The ceramic coating shall
provide a homogeneous, uninterrupted, non-conducting and impermeable layer
capable of providing corrosion resistance for a minimum of 1000 hours in
accordance with ASTM G 85. The use of sealers shall not be permitted. ]
2.1.4
Hydraulic Cylinders (Custom Design)
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NOTES: Alternate 2 shall be used when the hydraulic
cylinders are to be custom designed by the
manufacturer specifically for this project in
accordance with the design parameters.
Telescopic hydraulic cylinders shall be used only
for special retrofit applications where regular
single or double acting cylinders cannot be used.
Unless the designer needs to make the choices
because of unique criteria situations, the selection
of materials and configurations should remain as
Contractor's options.
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The hydraulic cylinder shall be of the [single] [double] acting [,
telescopic] type designed and manufactured [to be used under water and] to
meet the criteria stated in paragraph DESIGN PARAMETERS. [Telescopic
cylinders may be either single or double wall as necessary to provide the
best operating characteristics.] Material for the hydraulic cylinder shall
be a high strength carbon or alloy steel. Cylinder tubes which have been
welded shall be stress relief heat treated and [all welds shall be
radiographed including those on the end mounts] [designated welds shall be
radiographed as indicated]. Material for the piston rod shall be a high
strength [carbon or alloy steel with nickel and chrome plating] [stainless
steel with chrome plating] [carbon or alloy steel with a ceramic coating]
[_____]. [The exterior of the extending rods and tubes on a telescopic
cylinder shall be [nickel plated] [ceramic coated].] [The nickel plating
shall be a minimum of 75 micrometers 0.003 inch thick and shall be a high
phosphorous, electroless nickel process designed for corrosion protection.
The process shall be similar and equal to Enplate NI-425 by Enthone
Incorporated which has a phosphorous content of 10.5 percent to 12 percent
by weight.] [ The ceramic coating shall have a 200 micrometers 0.008 inch
minimum thickness, surface finish of 0.30 micrometers 12 microinches RMS
SECTION 15010A
Page 17
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