| In order that iron
screw stays may be approved of the same size as would be required
for mild steel, the iron must withstand the following tests:-
(a) Tensile Tests.- The tensile breaking strength
shall not be less than 21½ tons per square inch, with
an elongation of not less than 25 per cent measured on the
Standard Test Piece B or 30 per cent measured on the Standard
Test Piece B1.
(b) Bend Tests.- Test pieces either of the bar as
rolled, or turned down to 1 inch diameter, shall stand bending
cold until the sides are parallel and the space between the
two sides is not greater than the diameter of the test piece.
(c) Number of Tensile Tests.- The bars as rolled shall
be placed in batches of twenty, and one tensile test shall
be taken from each batch. If this is unsatisfactory two other
bars shall be selected for test, and should either of these
fail the batch shall be rejected.
(d) Number of Bend Tests.- One ordinary bend test
shall be taken from each batch, and a similar test piece from
each batch shall be lightly and evenly nicked on one side
with a sharp cutting tool and bent back at this point through
an angle of 180 degrees by pressure or by a succession of
light blows. The fracture must be clean, fibrous, free from
slag or dirt or any coarse crystalline structure. If either
of these is unsatisfactory, two other bars shall be selected
for test, and should either of these fail the batch shall
(e) In all cases the selection of the test pieces shall be
made by the Inspector or the Inspecting Officer.