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Diameter and length of core wire |
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|  MIL-E-19141D
l/16-inch wide and be symmetrical about the groove in the electrode cover-
2
ing. The maximum and minimum dimensions shall be located for each groove of
each electrode in the sample measured to the nearest 0.001 inch and recorded.
The maximum and minimum pair of dimensions which show the greatest difference
for the electrodes required to be measured as specified in 4.2.4 shall be used
to determine conformance to 3.2.2.
4.4.2.1 Diameter and length of core wire. In the course of making the
measurements specified in 4.4.2, the diameter and lengths of the core wire
shall be measured to determine conformance with 3.3.
4.4.3 Dielectric strength. When required (see 6.2.1), dielectric strength
of coverings shall be determined by the method specified on figure 2. Methods
other than the one shown, yielding the required results, may be used as alterna-
tives if such methods are acceptable to the Government.
4.4.4. Flaking and cracking of covering. When required (see 6.2.1), six
electrodes shall be tested for flaking and cracking tendency upon restarting
and during welding, in accordance with 4.4.4.1 and 4.4.4.2, respectively. The
welding current used shall be in the same range as that used in making the weld
test assemblies (see 4.4.5). The welding shall consist of depositing a bead
weld on a plate surface.
4.4.4.1 Flaking and cracking upon restart. Three of the six electrodes
specified in 4.4.4 shall be tested. The covering shall be grooved to the core
wire completely around the electrode at the midpoint of the length. The groove
shall be prepared by grinding with the edge of a grind stone (intersection of
flat-side of grind stone with its periphery). The core wire shall be uncovered
at the root of the groove to form a land 1/16 inch minimum along the length of
the electrode. The core wire shall not be undercut. The electrode shall be
consumed to the root of the groove in the covering when welding shall be stopped
without fusing coating beyond the groove. The half-length electrode shall be
removed immediately from the electrode holder and placed upon a flat steel
plate to cool until it can be held comfortably in the bare hand. After cooling,
the electrode shall be inserted in the electrode holder and welding resumed.
After the restart, the half-length electrode shall be consumed for 1 inch of
its length. Welding shall then be stopped and the arc end of the electrode
examined for conformance to 3.2.4.
4.4.4.2 Flaking and cracking during welding. The remaining three
electrodes shall be tested. The electrode shall be consumed to a stub not
over 2 inches in length. If flaking or cracking is observed during welding,
the welding shall be stopped immediately and the arc end of the electrode
examined for conformance to 3,2.4. If no flaking or cracking is observed
during welding, the 2-inch stub length of electrode, which is normally
discarded, shall not be examined.
4.4.5 Weld test assemblies (weld overlays). Weld test assemblies shall be
prepared with sample electrodes obtained in accordance with 4.2.4. Test assem-
blies shall consist of a minimum overlay of 4 square inches deposited in three
layers on a test piece 6 by 4 inches by 3/4 inch thick. The test piece shall
conform to MIL-S-22698, grade DH-36 or EH-36T. A record of the welding para-
meters (welding current, arc voltage, preheat and interpass temperature, and
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