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Reg. 126
FURNACES
Furnace Crown
| a) |
The furnace crown shall be made from one plate and
the seam connecting it to the furnace shall not fall
in line with any circumferential seam of the boiler
shell.
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| b) |
The furnace crown may be riveted
to the vertical portion of the firebox, or alternatively,
the joint may be fusion butt welded by the electric arc
process, provided the conditions as to fusion welding
in Regulation 125
are observed. Where the joint is to be welded the edges
of the furnace crown and the firebox body shall be beveled
in accordance with Fig. 3 or
Fig. 4. The depth of the
flange of the furnace crown plate from the commencement
of the curvature of the flanging radius shall be not less
than four times the plate thickness with a minimum of
1½ inches. On completion of welding the firebox
shall be effectively stress relieved by heat treatment
(see also Reg. 128). |
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