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|  MIL-E-19141D
number of layers) shall be included on the certificate of test (see 4.6). After
cooling, the finished weld surface shall be visually examined for conformance
to 3.4, then the surface of the overlay shall be ground smooth and five random
hardness readings taken. After hardness testing, the assembly shall be sec-
tioned to provide three coupons for macro-examination at 10X magnification in
the polished and etched condition.
4.4.6 Hardness. Hardness shall be measured by the Brinell method specified
in ASTM E 10. Rockwell hardness numbers converted to Brinell hardness numbers
shall not be used.
4.4.7 Chemical analysis. Chemical analysis shall be made by the testing
laboratory or the manufacturer, from a small sample of drilling, milling, chips
or slices-machined with tools of high-speed steel from pads of weld metal, for
deposits with electrodes deposited on plain low carbon-steel or base material of
chemical composition similar to the electrode deposit. The pads of weld metal
shall be a minimum of 1-1/2 by 1-1/2 inches by 1/2 inch high for deposits with
electrodes up to and including 3/16 inch diameter, and a minimum of 2 by 2 inches
by 1/2 inch for deposits with 1/4 inch diameter electrodes. The quantity Of
drillings, millings, chips or slices need be no more than necessary for satis-
factory analysis. The top surfaces shall be machined off and the samples for
chemical analysis shall be machined from the section immediately below, so
that no metal. shall be removed within 1/4 inch of the base metal. Chemical
analysis shall be made by wet chemical or spectrographic methods. In case of
dispute, chemical analysis by wet chemical methods shall be the basis for
acceptance. The pad shall be deposited as follows:
(a) Weld metal shall be deposited in multiple pass layers. Each
pass shall be deposited, so that its width is 1-1/2 to 2-1/2
times the core wire diameter of the electrode. Welds shall be
deposited using common production welding techniques.
(b) The pad may be quenched in hot water (above 180F) after each
pass, to speed cooling. If this technique is employed, the pad
should be cooled for approximately 1 minute prior to quenching,
and allowed to dry prior to the next pass.
(c) A record of the welding parameter, (welding current, arc voltage,
preheat and interpass temperature) base material and approximate
number of layers and passes shall be forwarded with the chemical
analysis when required by the using activity.
4.4.7.1 Chemical analysis (alternative method). Chemical analysis (wet
chemical or spectrographic) may be made on sample drillings, or slices taken
from deposited weld metal of groove welds. Extreme care to avoid contamination
of the sample shall be exercised when using this method of sampling for chemical
analysis; the drillings or slices shall be taken along the centerline of the
longitudinal axis of the deposited metal and from the upper third of the groove
weld thickness.
4.4.8 Covering moisture. The tendency for the electrode coverings to
generate gas, (especially hydrogen) which may be dissolved in the molten weld
metal and evolved after solidification of the weld metal, shall be determined by
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