Welding Repairs to Boilers and Pressure Vessels in Service

[Title 46 CFR 59.10]
[Code of Federal Regulations (annual edition) - October 1, 2006 Edition]
[Title 46 - SHIPPING]
[Chapter I - COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)]
[Subchapter F - MARINE ENGINEERING]
[Part 59 - REPAIRS TO BOILERS, PRESSURE VESSELS AND APPURTENANCES]
[Subpart 59.10 - Welding Repairs to Boilers and Pressure Vessels in Service]
[From the U.S. Government Publishing Office]

46SHIPPING22006-10-012006-10-01falseWelding Repairs to Boilers and Pressure Vessels in Service59.10Subpart 59.10SHIPPINGCOAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)MARINE ENGINEERINGREPAIRS TO BOILERS, PRESSURE VESSELS AND APPURTENANCES
Subpart 59.10_Welding Repairs to Boilers and Pressure Vessels in Service

Sec. 59.10-1 Scope.

(a) Repairs to boilers or pressure vessels in service may be
performed by welding provided the welding meets the applicable
requirements of part 57 of this subchapter.
(b) No repairs by welding shall be made except temporary emergency
repairs without prior approval of the Officer in Charge, Marine
Inspection. Emergency repairs shall be replaced with permanent repairs
meeting the requirements of this subchapter when the vessel returns to a
port in which an Officer in Charge, Marine Inspection, is located except
in the case of minor repairs which in the opinion of the Officer in
Charge, Marine Inspection, do not materially affect the safety of the
boiler or pressure vessel.
(c) Repair welding of power boilers, not meeting the requirements of
subpart 52.05 of this subchapter, is prohibited unless the stress is
carried by such other type(s) of construction complying with the
requirements of this subchapter, and where the adequacy of the boiler
design is not solely dependent upon the strength of the welds.
(d) Only welded repairs as specified in this subchapter are
permitted on boilers and pressure vessels. The welding repairs allowed
by this subpart apply only to boilers and pressure vessels fabricated of
carbon steel. Welding repairs to boilers and pressure vessels fabricated
of alloy steel will be given special consideration by the Commandant.
Such other method of repairs by means of welding not covered in this
subchapter shall be referred to the Commandant and may be authorized by
him, if in his opinion, it meets the intent of this subchapter.

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

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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 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.

Sec. 59.10-10 Corroded surfaces.

(a) Corroded surfaces in the calking edges of circumferential seams
may be built up by welding to the original thickness under the following
conditions:
(1) The thickness of the original metal to be built up between the
rivet holes and the calking edge shall not be less than one-fourth of
the diameter of the rivet hole, and the portion of the calking edge to
be thus reinforced shall not exceed 30 inches in length in a
circumferential direction.
(2) In all repairs to circumferential seams by welding, the rivets
shall be removed over the portions to be welded for a distance of at
least 6 inches beyond the repaired portion.
(3) After repairs are made the rivet holes shall be reamed before
the rivets are redriven.
(b) It is not permissible to build up or reinforce a grooved or
corroded area of unstayed internal surfaces by means of welding, except
that widely scattered pit holes may be built up by welding.
(c) Where external corrosion has reduced the thickness of flat
plates around hand holes to an extent of not more than 40 percent of the
original thickness and for a distance not exceeding 2 inches from the
edge of the hole, the plate may be built up by welding.
(d) Where stayed sheets have corroded to a depth not exceeding 40
percent of their original thickness, they may be reinforced or built up
by welding. Where the staybolts are fitted with riveted heads, the
staybolts in the reinforced area shall be renewed in accordance with the
provisions of Sec. 52.20-15 of this subchapter, but where the

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staybolts are fitted with nuts, the nuts may be removed and after
reinforcing has been applied, collars may be welded around the staybolts
in lieu of the nuts. Such reinforced areas shall not exceed 400 square
inches nor more than 30 inches in one direction. Two such areas in any
one plate may be reinforced: Provided, that the distance between the
reinforced surfaces is not less than 30 inches.
(e) When the corroded portion of a staybolted surface exceeds 400
square inches, it is permissible to make repairs by cutting out the
defective portion and replacing it with a new plate, the edges of the
new plate to be welded in position. In such cases, new staybolts shall
be fitted in accordance with the requirements of Sec. 52.20-15 of this
subchapter and where welding is performed through a line of staybolts,
welded collars as required by Figure 52.01-3 of this subchapter shall be
used to attach the staybolts.
(f) Eroded seams of welded pressure vessels may be repaired by
rewelding the wasted portion. The wasted section of the seam shall be
excavated sufficiently by grinding, flame or arc gouging or chipping to
ensure proper weld penetration. Rewelded seams shall be nondestructively
tested in accordance with section VIII, ASME Code.

Sec. 59.10-15 Rivets and staybolts.

(a) It is not permitted to reinforce or build up by welding the
heads of rivets or staybolts that have deteriorated. Such rivets or
staybolts shall be replaced. The seal welding of rivet heads to secure
tightness is prohibited.
(b) Where leaks develop around staybolts which are otherwise in good
condition, the nuts may be replaced with a beveled collar formed around
the end of the stay by means of welding. In such cases, the depth of
collar measured on the stay and the width measured on the plate, shall
be equal to one-half the diameter of the staybolt.

Sec. 59.10-20 Patches in shells and tube sheets.

(a) Unreinforced openings in the shells or drums of boilers or
pressure vessels, the diameter of which does not exceed the maximum
diameter of an unreinforced opening in accordance with Sec. 52.01-100
of this subchapter may be closed by the use of a patch or plate inside
the drum or shell and sealed against leakage by welding. Such plates
shall have a diameter of at least 2 inches larger than the diameter of
the hole and shall have a thickness equal to the thickness of the plate
to which it is attached. It is not permissible to insert such patches in
the shell or head flush with the surrounding plate unless the
requirements of this subchapter for Class I welded pressure vessels are
met.
(b) Portions of tube sheets which have deteriorated may be renewed
by replacing the wasted portion with a new section. The ligaments
between the tube holes may be joined by means of welding and staytubes.
Other acceptable means of lowering the stress on the repaired section
may be used if in the judgment of the Officer in Charge, Marine
Inspection, it is necessary.

Sec. 59.10-25 Stayed areas.

Welding repairs are permitted in staybolted areas or areas
adequately stayed by other means so that should failure of the welds
occur the stress will be carried by the stays. The welds shall be
located entirely within staybolted areas and shall not pass through the
outer row of stays.

Sec. 59.10-30 Seal welding.

Where leaks occur in riveted joints or connections, they shall be
carefully investigated to determine the cause. Such leaks may be made
tight by seal welding the edge, if, in the opinion of the Officer in
Charge, Marine Inspection, this will make a satisfactory repair.

Sec. 59.10-35 Wrapper plates and back heads.

Wrapper plates and back heads may be renewed in whole or repaired as
follows:
(a) Wrapper plates or backs heads shall be cut between two rows of
staybolts or on a line of staybolts where the thickness is approximately
the same as the original construction. If welding is employed on a line
of staybolts, the staybolts shall be fitted

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with a welded collar as required by Figure 52.01-3 of this subchapter.
(b) The edges of wrapper plates riveted to tube sheets and back
heads shall be removed by cutting out the rivets.
(c) The edges of existing plates and new plates shall be beveled by
chipping, flame cutting or grinding so as to form a suitable groove
whereby complete penetration of the weld metal will be obtained. The
edge preparation and preheat shall comply with the requirements of Sec.
59.10-5(h).
(d) The edges of the new plate shall be buttwelded and the plate
shall be riveted to the flanges of the tube sheet and back heads and the
staybolts renewed.
(e) Sections of wrapper plates of combustion chambers outside of
stayed areas may be repaired by welding provided the welded joints are
stress-relieved by means of controlled heat and the joints are
nondestructively tested.