N.Y. Comp. Codes R. & Regs. tit. 12, § 14-3.8
Welding repairs of cracks.
Department of Labor
- (d) Cracks between tube holes in water-tube boiler drums or in wrought or cast steel (but not cast iron) sectional headers may be repaired by welding, provided the plate thickness does not exceed one inch and further provided that there are no more than two such cracks in any one row in any direction, nor more than a total of four such cracks in any one drum or header. The tubes on each side of a cracked ligament shall be removed before any welding is done, and after the welding is completed, the tube holes shall be reamed or otherwise properly prepared for reinstallation of the tubes.
- (e) Cracks in plain circular, corrugated, Adamson ring or similar type furnaces may be repaired by welding, provided they are locally stress relieved as required by section 14-3.15 of this Subpart.
- (f) Cracks in the flat portion of tube sheets adjacent to furnaces in Scotch marine boilers require immediate replacement of the affected area.
- (g) Prior to repairing a crack between tube holes in a boiler, the tubes at each end of the crack shall be removed and, if considered necessary by the inspector, additional tubes shall be removed. When the welding is completed, the tube holes shall be reamed or otherwise properly prepared for reinstallation of the tubes.
(h) Circumferential cracks in the knuckle or turn of a flange of a furnace or flue opening or adjacent to a manhole opening of an unstayed head require immediate replacement of the affected area.
FIGURE 14-3.8(2)—RIVET AND STAYBOLD HOLE CRACKS
(i) Cracks radiating from rivet or staybolt holes may be repaired if the plate is not seriously damaged. If the plate is seriously damaged, it shall be replaced. The repair method shall be as follows:
- (1) Prior to welding, the rivets or staybolts from which the cracks extend and the adjacent rivets or staybolts shall be removed.
- (2) In riveted joints, tack bolts shall be replaced in alternate holes to hold the plate laps firmly.
- (3) The cracks shall then be prepared for welding by chipping, grinding or gouging.
- (4) In riveted joints, cracks which extend past the inner edge of the plate lap shall be welded from both sides.
- (5) Rivet holes shall be reamed before new rivets are driven.
- (6) Threaded staybolt holes shall be retapped and new staybolts properly driven and headed.
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(a) Removal of defects.
A repair of a defect, such as a crack in a welded joint or base material, may not be made until the defect has been removed. A suitable nondestructive examination method shall be used to assure complete removal of the defect. If the defect penetrates the full thickness of the material, the repair shall be made with a complete penetration weld such as a double butt weld or a single butt weld with or without backing.
Note:
Before repairing a cracked area, care should be taken to investigate its cause and to determine its extent. Where circumstances indicate that the crack is likely to recur, consideration should be given to removing the cracked area and installing a patch or other corrective measures.
(b) Cracks in unstayed areas.
Cracks in unstayed shells, drums or headers of boilers may be repaired by welding, provided the cracks do not extend between rivet holes in a longitudinal seam or parallel to a rivet seam within eight inches, measured from the nearest caulking edge. The total length may be welded, provided the complete repair is radiographed and stress relieved in accordance with section 14-3.15 of this Subpart. Cracks in unstayed areas shall be repaired as specified in figure 14-3.8(2) or by other equivalent methods.
(c) Cracks in unstayed furnaces.
Cracks of any length in unstayed boiler furnaces may be welded provided the welds are thermally stress relieved in accordance with section 14-3.15 of this Subpart. Welds applied from one side only shall be subject to the approval of the inspector. Field repair of cracks at the knuckle or the turn of the flange of the furnace opening require immediate replacement of the affected area. See Figure 14-3.8 (1) which follows:
FIGURE 14-3.8(1)—UNSTAYED BOILER FURNACES
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