Reg. 556, Reg.
557, Reg. 558
Compensating plates shall be of mild steel and, before
attachment, shall be closely to the plates to which
they are to be connected. Any welds therein shall be
on the transverse centre line.
Definition of the terms Fusion Weld
The terms fusion weld is, for the purpose
of this chapter applicable to all welded seams made
by the metal arc process with covered electrodes or
by any other electric arc process in which the arc steam
and the deposited weld metal are shielded from atmospheric
The relevant provisions of this Chapter shall also apply
to the single run or heavy run welding process and that
welded boilers manufactured by that process shall comply
with all regulations of this Chapter excepting those
in which divergence is necessary solely because of special
requirements essential for the most efficient utilisation
of that process. Thus all regulations governing quality
of material construction, workmanship, and testing (both
non-destructive and otherwise) are applicable.
Where welded shells conforming to the regulations of
this Chapter are made by single or heavy run process
it shall be understood that regulation
and 559 do not
apply in their entirety. The method of making the welds
shall be approved by the Inspecting Authority.
Method of Welding
Provided the requisite quality of welding is achieved
the seams may be welded from both sides of the plates
or from one side of the plate. Before the second side
of the plate is welded, the weld metal at the bottom
of the first side shall be removed by grinding, chipping,
machining or other approved method.
Additional runs of metal shall be deposited at both
surfaces of the welded seams to ensure that the weld
metal at the level of the surface of the plate is refined
as far as possible. The surfaces of the weld which are
to be subsequently radiographed shall thereafter be
machined or ground so as to provide smooth contours
and to be flush with the respective surfaces of the
plate. In the case of circumferential shell seams welded
by submerged arc or any other approved automatic process
producing a similar surface finish, such circumferential
welds, need not be flush dressed, subject to their surface
finish and shape being acceptable to the Inspecting
Authority. There shall be no under-cutting of the junctions.
The positions of the welds shall be marked permanently
to facilitate their location.
When affixing standpipes, branchpipes, seatings, compensation
plates, doubling plates or manhole frames, not less
than two runs of metal shall be deposited at each weld.
Each run of weld metal shall be thoroughly cleaned and
freed from slag before the next run is deposited.