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Page Title:
Controlled chemical composition |
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|  MIL-E-22200G
4.4.1.1 Electrode covering definitions.
4.4.1.1.1 Dry batch. A dry batch of covering mixture is defined as the
quantity of dry covering ingredients mixed at one time in one mixing vessel. A
dry batch may be used singly or may be subsequently sub-divided into quantities
to which the liquid binders may be added to produce a number of wet mixes.
4.4.1.1.2 Dry blend. A dry blend is defined as one or more dry batches
mixed in a mixing vessel and combined proportionately to produce a uniformity of
mixed ingredients equal to that obtained by mixing the same total amount of dry
ingredients at one time in one mixing vessel.
4.4.1.1.3 Wet mix. A wet mix is defined as the combination of a dry batch
or dry blend, or portion thereof, and liquid binder ingredients at one time- in
one mixing vessel.
4.4.1.2
Identification of covering mix.
4.4.1.2.1 Wet mix. Covering identified by wet mix shall consist of a
single wet mix for each lot of electrodes.
4.4.1.2.2 Controlled chemical composition. Covering identified by
controlled composition (rather than by wet mix) shall consist of one or more wet
mixes and shall be subjected to sufficient tests, both before and after it has
been applied to the core wire, to assure that all wet mixes within the lot are
equivalent. These tests shall include chemical analysis, the results of which
must fall within the manufacturer's acceptance limits. The identification of the
test procedure and the results of the tests shall be recorded. The following
additional conditions shall apply:
(a) Each wet mix shall be chemically analyzed by approved methods (see
4.3.2.3).
(b) Chemical analyses shall be certified by the laboratory and percent
variation from standard made available to the Government
representative.
(c) Wet mixes conforming to established covering mixture chemistry
control for a specific MIL-type electrode shall be appropriately
identified and segregated to avoid mixups.
4.4.1.3 Heat of core wire. A heat of metal for core wire is defined by one
of the following, depending on the method of melting and refining the metal.
(a)
Where slag-metal or gas-metal reactions occur in producing the
metal (for example, open hearth, electric-arc, basic oxygen,
argon-oxygen), a heat is the material obtained from one furnace
melt.
(b)
Where significant chemical reactions do not occur in producing the
metal (for example, induction melting in a controlled atmosphere
or in a vacuum), a heat is an uninterrupted series of elts from
one melting furnace under the same melting conditions, each melt
conforming to the chemical composition range approved by the
purchaser of the material (the producer of the filler metal).
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