[Code of Federal Regulations]
[Title 46, Volume 2]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR59.10-5]

[Page 282-283]
 
                           TITLE 46--SHIPPING
 
   CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)
 
PART 59_REPAIRS TO BOILERS, PRESSURE VESSELS AND APPURTENANCES--Table of Contents
 
Subpart 59.10_Welding Repairs to Boilers and Pressure Vessels in Service
 
Sec. 59.10-5  Cracks.

    (a) Cracks extending from the calking edge of plates to the rivet 
holes of circumferential joints may be welded provided the cracks are 
veed out so that complete penetration of the weld metal is secured.
    (b) Circumferential cracks from rivet hole to rivet hole in girth 
joints may be welded provided there are not more than three consecutive 
cracked ligaments nor more than a total of six cracked ligaments in any 
one girth joint.
    (c) Cracks in staybolted plates may be welded provided they are 
located entirely within staybolted areas and the total length of any 
crack or series of consecutive cracks does not exceed two staybolt 
pitches.
    (d) Cracks in plain, circular or Adamson ring or similar type 
furnaces may be welded provided any one crack does not exceed 12 inches 
in length and after completion the weld is stress-relieved. Cracks in 
corrugated furnaces may be repaired by welding provided any one crack 
does not exceed 20 inches in length.
    (e) Fire cracks may be welded at riveted door openings extending 
from the edge of the plate, but not more than 2 inches beyond the 
centerline of the rivet holes.
    (f) Cracks may be welded between tube holes in the shell of water 
tube boiler drums, provided there are not more than two cracks in any 
one row in any direction, nor more than a total of four cracks in a 
drum, and further provided the welding meets the requirements of this 
subchapter for Class I welded pressure vessels and is approved by the 
Commandant.
    (g) Cracks that occur in superheater manifolds, water wallheaders, 
water drums, sectional headers, and other appurtenances including steam 
manifolds of water tube boilers may be repaired in accordance with 
paragraph (h) of this section if the repair is approved.
    (h) All cracks permitted to be repaired under this subpart shall be 
excavated to sound metal by grinding, flame or arc gouging or chipping 
out the defective metal to form a clean welding groove. The first two 
methods of excavation are preferable. Either a V groove or U groove 
wherein complete

[[Page 283]]

penetration of the weld metal is secured may be used. After excavation 
is completed and prior to welding, the excavated area shall be examined 
by magnetic particle, dye penetrant, or other acceptable test method. 
When the reverse side of the weld is accessible the root of the weld 
shall be chipped or ground out to insure a clean surface of the 
originally deposited metal and the resultant groove welded to obtain a 
sound weld having complete penetration. When the weld cannot be back 
chipped because the reverse side is inaccessible, a backing strip or 
other approved means of assuring full penetration shall be employed.
    (i) During welding of cracks a preheat shall be maintained by 
controlled temperatures. The degree of preheat shall be determined by 
the rules listed in accordance with the materials P-number groupings of 
PW-38, section I, Appendix R, section VIII and Table Q. 11.1, section IX 
of the ASME Code. For thicknesses exceeding three-fourths inch, suitable 
U grooves should be employed. A welding sequence shall be used so as to 
equalize welding stresses.
    (j) Postweld heat treatment of repaired cracks shall be performed in 
accordance with the rules specified in PW-39, section I and UW-40, 
section VIII of the ASME Code for boilers and pressure vessels 
respectively.
    (k) Welded repairs of cracks shall be nondestructively tested in 
accordance with the rules specified in PW-40, section I, and UW-51, 
section VIII of the ASME Code for boilers and pressure vessels 
respectively.
    (l) After cracks originating in tube or rivet holes are repaired by 
welding, the holes shall be properly reamed and the weld reinforcing 
ground flush with the plate in way of rivet heads.
    (m) Flat tube sheets in fire-tube boilers which have corroded or 
where cracks exist in the ligaments may be repaired by welding.
    (n) Welding repairs to drums of power boilers, except as otherwise 
permitted in this subpart, are prohibited.