28
Molesworth’s pocket-book
Admiralty Tests fob Steel.
TENSILE AND EXTENSION TESTS.
1. Strips cut lengthwise or crosswise of the plate to have
an ultimate tensile strength of not less than 26, aud not
exceeding 30 tons per square inch of section, with an elonga-
tion of 20 per cent, in a length of 8 inches.
TEMPERING TEST.
2. Strips cut lengthwise of the plate, inch wide, heated
uniformly to a low cherry-red, and cooled in water of 82°
fahrenheit, must stand bending in a press to a curve of
which the inner radius is one and a half times the thickness
of the plates tested.
3. The strips are to be cut in a planing machine, and are
to have the sharp edges taken off.
4. The ductility of every plate is to be ascertained by the
application of one or both of these tests to the shearing, or
by bending them cold by the hammer on the Contractor’s
premises, and at his expense.
5. All plates to be free from lamination and injurious
surface defects.
6. One plate to be taken for testing by tensile, extension
and tempering tests from every invoice, provided the number
of plates does not exceed 50. If above that number, one for
every addition of 50, or portion of 50. Plates may be re-
ceived or rejected without a trial of every thickness on the
invoice.
7. The pieces of plate cut out for testings are to be of
parallel width from end to end, or for at least 8 inches of
length.
When the plates are ordered by thickness, their weight is
to be estimated at the rate of 40 lbs. per square foot for
plates of 1 inch thick, and in proportion for plates of all
other thicknesses: the weight so produced is not. to be ex-
ceeded, but a latitude of 5 per cent, below this will be