Seawater Valves
MIL-V-24287
Aluminum Bronze
Cast
MIL-B-23921 ASTM B-271
(min. 4% Ni)
Wrought
MIL-B-24059
Tubing
ASTM-B-210
b.
CLASS 2, Material of known properties. Materials and components
in this class have not been used extensively in similar applications but are
classed as conventional due to identification by military specifications,
federal specifications, or recognized American commercial standards such as
those published by the American Society of Mechanical Engineers or the
American Society for Testing and Materials. Materials or components
available as standard stock items built to a recognized commercial or Federal
standard will be considered in this class. Examples of materials that are
presently considered to be in this class are certain types of aluminum,
titanium, and some high-strength low-alloy steels. The determination of
acceptable properties and
allowable operating stress values will be based
on the recommendations and supporting information provided by the applicant.
For pressure vessel and other structural parts, the applicant should
submit the following information in justification of the use of a Class 2
material:
(1) The applicable military, federal, or industrial specification
involved with a detailed list of exceptions or additions to comply with ANSI/
ASME PVHO 1.
(2) Material properties for the base metal in the condition to be
used and, if the material is to be welded, for the weld metal and the heat-
affected-zone material.
(3) Tensile properties including tensile strength, yield strength,
percent elongation, reduction of area, rate of loading, elastic modulus and
engineering stress-strain curve (tension and compression) for the material.
The material specimens tested should represent any applicable defects and
variations in material properties introduced by manufacturing and fabrication
processes.
(4) Impact and fracture toughness properties over a range of
temperatures sufficient to fully define the fracture characteristics of the
material for the intended service environment (e.g., transition temperature
and shelf energy values). Desirable tests would include Charpy V-notch
transition curves and dynamic tear as well as drop-weight tests per ASTM
procedures, and/or explosive bulge tests. Where appropriate, the applicant
should show that the material's fracture toughness properties in the
applicable environment (e.g., marine, seawater, air) are adequate for its
intended use. In this regard, a fracture mechanics type of test may be
useful to study the effect of seawater on fracture resistance.
(5) Proof of weldability and fabricability (if fabrication process
includes welding). This would include results of tests such as prescribed in
MIL-STD-1693 (YD) Fabrication Welding and Inspection of Hyperbaric Chambers
Previous Page
