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Cold Bends.-(a) Test pieces shall be sheared lengthwise
or crosswise from plates or bars, and shall not be less than
1½ inches wide, but for small bars the whole section
may be used. For rivet bars bend tests are not required.
b) In all cold bend tests, on samples 0.5 inch in thickness
and above, the rough edge or arris caused by shearing may
be removed by filing or grinding, and samples 1 inch in thickness
and above may have the edges machined, but the test pieces
shall receive no other preparation. The test pieces shall
not be annealed unless the material from which they are cut
is similarly annealed in which case the test piece shall be
similarly and simultaneously treated with the material before
testing.
(c) (i) For bend
test of plates of all grades of steel, the test piece shall
withstands, without fracture, being bent cold through 180o
around a mandrel, the radius of which shall have a
relationship to the plate thickness as given below:
Tensile strength
Mandrel
Radius
36 - 49 kg./mm2
1 T
41 - 57 kg./mm2
1 T
45 - 64 kg./mm2
1.5 T
where T = Plate thickness
(ii)
For cold bend test of sections and bars, the test piece shall
withstand, without fracture, being doubled over until the
internal radius is equal to that shown in Table under
regulation 16 and the limbs are parallel.
(d) For small sectional material these bend tests may be
made from the flattened bar.
(e) Bend tests may be made either by pressure or by blows.
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