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|  MIL-S-46777C
3.15.1.2 Fiberglass fabrication. Fiberglass reinforced plastic (FRP) shall be smooth surfaced
and free from bubbles, glazing cracks, and discontinuities and shall have a uniform FRP
thickness. All edges and openings of FRP shall be completely sealed to prevent water intrusion.
The FRP shall be free of parting agents which impair paint adhesion. Welding, bonding,
connections, and fabrication of the FRP shall be in accordance with the recommended methods
of the manufacturer of the material for this application.
3.15.2 Welders and welding.
3.15.2.1 Welders. Before assigning any welder to manual welding work covered by this
specification, the contractor shall provide the contracting officer with certification that the
welder has passed qualification tests as prescribed by any of the following listed codes for the
type of welding ooperation to be performed and that such qualification is effective as defined by
the particular code:
AWS D1.1, Structural Welding Code, Section 5, Qualification.
ASME Boiler and Pressure Vessel Code, Section IX, Welding Qualifications.
Equal welder qualification program, subject to Government approval.
3.15.2.2 Metal welding. Welding shall be in accordance with the AWS and ASME codes,
the American Welding Society's Welding Handbook, and as specified herein. Welds shall
provide the maximum notch toughness and fatigue strength with a minimum of residual stresses.
All welds made on high stress members shall be made from core or heavy-coated electrodes, gas
shielded, or submerged arc. Electroslag and electrogas processes, when available, shall be
included for use on heavy sections, 1 inch or more in thickness. Fillet welds shall be provided,
when necessary, to reduce stress concentrations. The surfaces to be welded shall be free from
scale, paint, grease, and other foreign matter. When multiple layers of weld metal are required,
each layer, or each layer after the third pass with multipass welding process, shall be throroughly
cleaned before depositing another layer. All welded parts and assemblies shall be free from
cracks and other imperfections that may reduce the effectiveness of the part or assembly. After
welding, all weldments shall be free from slag (except mill scale), flux, weld spatter, and other
factors which affect the qualifty of the weld. Except for vertical welding of the electroslag
process, the work shall be positioned for flat welding whenever practicable. No undercuts or
overlays will be permitted on any weldment. Where different metals are welded to each other,
filler metal having strength of the lower strength material shall be used. When the same metals,
or metals having similar properties are used, the deposited filler metal shall develop the full
design strength of the particular weld joint or weldment. Mechanical properties of all welds shall
be such that welds will transmit stress without failure or permanent deformation when subjected
to any test specified in this specification. Weld joints exceeding 50,000 psi shall be inspected for
soundness.
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