MIL-DTL-82020C(YD)
Unless otherwise specified, none of the above shall be interpreted to mean that the use of used or
rebuilt products are allowed under this specification.
3.3.1 Manganese steel castings. All components of the track fittings shall be manganese steel
castings having a chemical composition specified herein, unless otherwise specified in the
applicable drawings.
3.3.1.1 Chemical composition. Manganese steel castings shall conform to the following
requirements as to chemical composition:
Carbon, percent
1.00 to 1.40
Manganese, percent, minimum
12.00
Phosphorus, percent, maximum
0.10
Sulfur, percent, maximum
0.05
3.3.1.2 Heat treatment. Castings shall be heat treated at not less than 1,850 degrees Fahrenheit
(°F) (1 010 degrees Celsius (° C)) and preferably at 1,900 °F (1 038 °C) for not less than 2 hours
or for 1 hour per inch of casting section thickness, whichever is greater. Casting shall be cooled
by water quenching.
3.3.2 Steel. Steel for base plates, cover plates, and hold downs and stops, shall conform to
ASTM A 36 or ASTM A 283 as required by applicable drawings.
3.4 Drawings. The switches and frogs shall be constructed in accordance with NAVFAC
drawings listed in 2.1. Drawings forming a part of this specification are engineering design
drawings. The contractor shall be responsible for preparing shop drawings. Where tolerances
provided could cumulatively result in incorrect fits, the contractor shall provide tolerances within
those prescribed on the drawings to ensure correct fit, assembly, and operation of the items.
Proposed changes by the contractor to the government furnished design drawings shall be
approved by the contracting officer. No deviation from the prescribed dimensions or tolerances
shall be permissible without prior approval of the contracting officer.
3.5 Identification marking. Identification marking shall be cast into each unit in a location easily
visible after installation. Required information shall include as a minimum:
a.
Manufacturer and location of foundry.
b.
Type, class, and style or pattern number.
c.
Date of manufacture.
d.
Radius (for switches).
e.
Angle (for rigid frogs).
f.
Radius of curvature (for radius type frog).
g.
Applicable rail section.
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