Figure 7-63.Guided-bend test specimens.
test piece by using a hydraulic press or similar machine.
When the proper precautions are taken, a blacksmiths
forging press or hammer can be used to complete the
bending operation. If a crack more than 1/16 inch devel-
ops during the test, stop the bending because the weld
has failed; otherwise, bend the specimen flat. After
completing the test, measure the distance between the
scribed lines and call that measurement (y). The percent-
age of elongation is then determined by the formula:
Requirements for a satisfactory test area minimum
elongation of 15 percent and no cracks greater than 1/16
inch on the face of the weld.
You use the GUIDED-BEND TEST to determine
the quality of weld metal at the face and root of a welded
joint. This test is made in a specially designed jig. An
example of one type of jig is shown in figure 7-62.
The test specimen is placed across the supports of
the die. A plunger, operated from above by hydraulic
pressure, forces the specimen into the die. To fulfill the
requirements of this test, you must bend the specimen
180 degreesthe capacity of the jig. No cracks should
appear on the surface greater than 1/8 inch. The face-
bend tests are made in this jig with the face of the weld
in tension (outside), as shown in figure 7-63. The root-
bend tests are made with the root of the weld in tension
(outside), as shown in figure 7-63.
Figure 7-64 shows a machine used for making the
guided-bend test. It is used in many welding schools and
Figure 7-64.Testing machine for making guided-bend tests.