Hitherto there has been some prejudice against steel rivets, and
while this may have some foundation when iron plates are used, it is
certainly baseless when steel plates are concerned. The United States
government has clearly demonstrated this. All the ships of the new navy
have steel boilers, riveted with steel rivets, and an examination of
the character of the material prescribed and the severity of the tests
to which it is subjected show that these steel-riveted steel boilers
are probably the best boilers ever constructed.
United States Government Requirements for Boiler Rivets.
They are subjected to the most severe hammer tests, such as flattening
out cold to a thickness of one-half the diameter, and flattening out
hot to a thickness of one-third the diameter. In neither case must they
show cracks or flaws.
_Kind of Material._—Steel for boiler rivets must be made by either the
open-hearth or Clapp-Griffith process, and must not show more than .035
of one per centum of phosphorus nor more than .04 of one per centum of
sulphur, and must be of the best quality in other respects.
Each ton of rivets from the same heat or blow shall constitute a lot.
Four specimens for tensile tests shall be cut from the bars from which
the lot of rivets is made.
_Tensile Tests._—The rivets for use in the longitudinal seams of boiler
shells shall have from 58,000 to 67,000 pounds tensile strength, with
an elongation of not less than 26 per centum; and all others shall have
a tensile strength of from 50,000 to 58,000 pounds, with an elongation
of not less than 30 per centum in eight (8) inches.
_Hammer Test._—From each lot twelve (12) rivets are to be taken at
random and submitted to the following tests:
Four (4) rivets to be flattened out cold under the hammer to a
thickness of one-half the diameter without showing cracks or flaws.
Four (4) rivets to be flattened out hot under the hammer to a thickness
of one-third the diameter without showing cracks or flaws—the heat to
be the working heat when driven.
Four (4) rivets to be bent cold into the form of a hook with parallel
sides, without showing cracks or flaws.
_Surface Inspection._—Rivets must be true to form, free from scale,
fins, seams and all other unsightly or injurious defects.
In view of the fact that the government is using many hundred tons of
these rivets, shown by the records of the tests to be vastly superior
to any iron rivet made, in all the essentials of a good rivet, it would
seem that it would benefit the boiler maker, the purchaser of the
boiler and also the maker of the rivet by adopting a standard steel
rivet to be used in all steel boilers.