22 FIG.
9 - Fusible Metallic Backing a.
Fusible Backing Strip b.
Structure Backing Fusible
Metallic Backing In
this method, the weld penetrates into and fuses with the backing material which
either temporarily or permanently
becomes an integral part of the assembly. Backing
strips, of metal compatible with the metal being welded, may be used (Fig. 9a.)
or a joint may be so located
that a part of the structure forms the backing (Fig. 9b.). It is important that
the contact surfaces be clean
and close together, or porosity and leakage of molten weld metal may occur.
