15 Supporting
Molten Weld Metal a. The
Need for Molten Weld Metal Support Submerged
arc welding creates a large volume of molten metal which remains fluid for an
appreciable period
of time. It is essential that this molten metal be supported and contained until
it has solidified. b. Weld
Backing Methods to Secure Molten Support There
are five generally used ways of supporting molten weld metal:
Non-fusible backing
Submerged arc flux backing
Root backing Weld
backing Fusible
metallic backing The
first two employ temporary backing which is removed after the weld is completed.
In the other three, the backing
becomes a part of the completed joint. 1.
Non-Fusible Backing Copper
backing is a frequently used non-fusible backing in the welding of steel. It is
used when the base metal
does not have sufficient mass to provide adequate weld metal support, or when
complete weld penetration
must be obtained in one pass. Copper backing is especially useful for welding
gage thickness materials.
Several types of copper-backed joints are shown in Fig. 3.
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