WELDING OPERATIONS I - OD1651 - LESSON 1/TASK 1
(b) High-carbon electrodes should not be used for welding tool
steels. The carbon picked up from the base metal by this filler
metal will cause the weld to become glass hard; whereas, the
mild-steel weld metal can absorb additional carbon without
becoming excessively hard. The welded part should then be heat-
treated to restore its original properties.
(c) When welding with stainless steel electrodes, the edges of
the plates should be preheated to prevent the formation of hard
zones in the base metal. The weld metal should be deposited in
small string beads to keep the heat input down to a minimum. In
general, the application procedure is the same as that required
for high-carbon steels described in paragraph 6b(2) beginning on
page 54.
d.
High Yield Strength, Low Alloy Structural Steels.
(1) General. High yield strength, low alloy structural steels
are special steels that are tempered to obtain extreme toughness
and durability. The special alloys and general make-up of these
steels
require
special
treatment
to
obtain
satisfactory
weldments.
(2) Welding Techniques.
(a) Reliable welding of high yield strength, low alloy
structural steels can be performed by using the correct
electrodes.
Hydrogen is the number one enemy of sound welds in
Therefore, use only low hydrogen (MIL-E-18038 or
MIL-E22200/1) electrodes to prevent cracking. Underbead cracking
is caused by hydrogen picked up in the electrode coating,
released into the arc, and absorbed by the molten metal.
(b) Electrodes must be kept dry to eliminate absorption of
hydrogen.
If the electrodes are in an airtight container,
immediately upon opening the container, place the electrodes in a
ventilated holding oven set at 250 to 300 F. In the event that
the electrodes are not in an airtight container, put them in a
ventilated baking oven and bake for 1 to 1 1/4 hours at 800 F.
Baked electrodes should, while still warm, be placed in a holding
oven until used.
Electrodes must be kept dry to eliminate
absorption of hydrogen.
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