MIL-STD-2193 Ship Hydraulic System ComponentsThis standard provides design, construction, and testing requirements that are common to most components used in ship hydraulic power transmission and control systems. This standard does not establish configuration requirements, pressure, flow, or performance requirements for any specific component.

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MIL-STD-2193C(SH)

TABLE I.  Metal coatings.

5.1.2.1  Cadmium and zinc plating.  Cadmium and zinc plating shall not be used for internal parts or on internal surfaces in contact with hydraulic fluid.  This restriction does not prohibit the use of zinc or cadmium-plated

standard parts such as nuts, bolts, and screws in locations that are external to the system if there is no danger of fluid contamination.

5.1.2.2  Aluminum alloys.  Aluminum alloys shall be anodized in accordance with MIL-A-8625 and shall be resistant to stress corrosion cracking.

5.1.2.3  Ferrous alloys.  External surfaces of ferrous alloys with a chromium content of less than 12 percent

shall be protected against corrosion by the use of one of the platings or coatings listed in table I or by painting with a two-component system epoxy-polyamide coating.  The coating shall be in accordance with MIL-DTL-24441,

MIL-DTL-24441/20 (formula 150), or MIL-DTL-24441/21 (formula 151).

5.1.3  Plastic parts.  Synthetic materials for use as seals, guides, wipers, and so forth shall conform to the applicable specifications for these parts.  Other nonmetallic parts may be used subject to the limitations of the applicable detail specification when verified to be compatible with all fluids in accordance with the immersion test of 5.3.1.7.

5.1.4  Prohibited materials.  The following materials shall not be used unless specifically permitted herein:

a.    Toxic materials.

b.    Zinc or zinc-plated materials (see 5.1.2.1). c.    Mercury (see 5.1.5).

d.        Magnesium or magnesium-based alloys. e.        Radioactive materials.

f.     Asbestos.

g.    Cadmium (see 5.1.2.1).

h.    Beryllium [beryllium is acceptable as a small percentage (less than three percent) alloying material].

5.1.5  Mercury contamination.  The component or any component parts shall not come in direct contact with mercury, mercury compounds, or mercury bearing instruments or devices employing only a single boundary of containment during manufacture, tests, or inspections.  No mercury or mercury bearing parts shall be installed or used in the component.

5.2  Construction.

5.2.1  Standard parts.  Standard parts (per approved Government and industry specifications and standards) shall be used whenever suitable for the purpose and shall be identified and numbered in accordance with the requirements of ASME Y14.100.  Where permitted by the component specification, commercial utility parts, such as screws,

bolts, nuts, and cotter pins may be used, provided they possess equivalent properties and are replaceable by the standard parts without alteration, and provided that both the commercial parts and the corresponding standard part numbers are included on the drawings required by the component specification.  For standard commercial components, this can be accomplished with a cross reference between commercial utility parts and standard parts.

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