LPD-1 LPD-1
SHIP SYSTEMS ISE ADVISORY NO. 011-87
MAIN PROPULSION BOILER (NON-NUCLEAR)
DOWNCOMER TUBE BUTT WELDED JOINTS
NAVSSES PHILADELPHIA PA MSG 132100Z MAY 87
REF: A. MIL-STD-22, JOINT P-3, FIGURE 3
1. SUMMARY: POTENTIAL PROBLEM OF TUBE CRACKING IS PRESENTED.
AFFECTED SHIPS ARE IDENTIFIED. INSPECTION REQUIREMENTS AND CORREC-
TIVE ACTIONS ARE PROMULGATED. END SUMMARY.
2. USS VANCOUVER (LPD-2), USS LASALLE (AGF-3), USS RALEIGH (LPD-1) AND
POSSIBLY USS MARS (AFS-1) HAVE EXPERIENCED CIRCUMFERENTIAL CRACKING
OF DOWNCOMER TUBES AT NOTCHES WHICH RESULTED FROM TUBE END
PREPARATION TO ACCEPT BACKING RINGS. DRIVING MECHANISM FOR THE
CRACKING HAS BEEN DETERMINED TO BE CORROSION FATIGUE. PROBLEM WAS
ORIGINALLY BELIEVED TO BE LIMITED TO NON-TAPERED TRANSITIONS FROM
BACKING RING PREPARATION TO TUBE INSIDE DIAMETER. HOWEVER, THROUGH
WALL CRACKS HAVE ALSO OCCURRED IN CONFIGURATIONS SHOWING A 45
DEGREE (ONE TO ONE TAPER) TRANSITION.
3. REFERENCE A SHOWS CONFIGURATION FOR BUTT WELDED JOINTS INCOR-
PORATING PERMANENT BACKING RINGS. THIS JOINT REQUIRES A FOUR TO ONE
TAPER (APPROXIMATELY 14 DEGREES) AND A 1/16 INCH RADIUS AT THE
TRANSITION FROM THE BACKING RING RECESS TO THE TUBE INSIDE DIAMETER.
4. A SURVEY OF BOILER DRAWINGS HAS BEEN CONDUCTED BY NAVSSES.
SHIPS WITH DRAWINGS INDICATING DOWNCOMER TUBE BUTT WELDS NOT
CONFORMING TO REFERENCE A ARE AS FOLLOWS:
NUMBER OF TAPER
SHIPS BOILERS MANUFACTURER (RATIO OR DEGREE)
AD 41, 42 8 CE 18 DEGREES
43, 44
AFS 1 21 B AND W (NOTE 1)
THROUGH 7
AOE 4 4 B AND W 30 DEGREES
AO 177, 178 10 CE 18 DEGREES
179, 180, 186
CV 60, 61 16 B AND W (NOTE 1)
CV 62 8 B AND W (NOTE 2)
CV 63, 64 16 FW 30 DEGREES
CV 66 8 FW 25 DEGREES
DD 946 4 B AND W (NOTE 1)
DDG 2, 3, 7, 8, 32 B AND W (NOTE 1)
10, 11, 12, 13
DDG 20, 21, 22 12 B AND W (NOTE 1)
DDG 37, 38, 39 12 FW 30 DEGREES
FF 1052, 1053, 68 CE 3/1
1054, 1055, 1058,
1060, 1062, 1064,
1066, 1067, 1070,
1071, 1074, 1076,
1078 THROUGH 1097
LHA 1 THROUGH 5 10 CE 3/1
LHD 1 THROUGH 5 10 CE 3/1
LKA 113 THROUGH 10 CE 3/1
117
LPD 1 THROUGH 6 12 B AND W (NOTE 3)
LPH 12 2 CE 3/1
LSD 36 2 CE 3/1
NOTE 1: TAPER NOT DIMENSIONED ON DRAWINGS.
NOTE 2:
TAPER NOT DIMENSIONED ON DRAWINGS. SHIP IS CURRENTLY IN
SHIP'S LIFE EXTENSION PROGRAM (SLEP). ACTION ALREADY
IDENTIFIED.
NOTE 3:
DRAWINGS SHOW NO TAPER. ACTUAL SHIPBOARD CONFIGURATIONS
HAVE VARIABLE TAPERS. THROUGH THE WALL CRACK WAS
PRESENT ON 45 DEGREE (ONE TO ONE) TAPER.
5. NAVSSES RECOMMENDS THAT BOILER DOWNCOMERS OF SHIPS LISTED IN
PARAGRAPH 4 ABOVE BE INSPECTED AT NEXT ROUTINE 18 MONTH WATERSIDE
INSPECTION BY A CURRENTLY CERTIFIED STEAM GENERATING PLANT
INSPECTOR (SGPI). IF NEXT WATERSIDE OPENING IS DURING A SCHEDULED
MAINTENANCE CYCLE, NAVSSES BOILER INSPECTORS WILL EVALUATE THESE
DOWNCOMER JOINTS.
6. INSPECTION RESULTS ARE TO BE DOCUMENTED IN BOILER INFORMATION
AND REPAIR MANAGEMENT INFORMATION SYSTEM (BIRMIS). POSITIVE AND
NEGATIVE RESULTS SHOULD BE INCLUDED. IF INSPECTION DOES NOT COINCIDE
WITH SCHEDULED ROUTINE BOILER INSPECTION, ENTER AS A SPECIAL INSPEC-
TION. REQUEST NAVSEA AND NAVSSES BE INFORMED BY MESSAGE OR SPEED-
LETTER WHEN EACH INSPECTION IS COMPLETED AND RESULTS ARE RECORDED
IN BIRMIS.
7. CORRECTIVE ACTIONS SHOULD BE PURSUED AS FOLLOWS:
A. IF CRACKS ARE FOUND, THEY MUST BE GROUND OUT AND SATISFAC-
TORY NDT CONDUCTED. IF DEPTH OF GRIND OUT REDUCES REMAINING WALL
BELOW 2/3, CONTACT NAVSSES FOR DETAILED REPAIR GUIDANCE. TAPER IN
CRACKED TUBES AND ALL OTHER SIMILAR TUBES OF THAT BOILER ARE TO BE
GROUND TO FOUR TO ONE TAPER REQUIREMENT OF REFERENCE A. RESTORA-
TION OF TAPER IN ACCESSIBLE HEADER DOWNCOMERS SHOULD BE ADDRESSED
ON A SHIP BY SHIP BASIS.
B. IF NO CRACKING IS PRESENT AND IF TAPERS GREATER THAN 30
DEGREES ARE FOUND, FAIR IN BY A HAND GRINDING TO ACHIEVE TAPER AND
RADIUS CONFIGURATION OF REFERENCE A. PERFORM GRINDING AT NEXT
SCHEDULED INDUSTRIAL AVAILABILITY. THE FOLLOWING ARE RECOMMENDED
TOOLS AND PROCEDURES FOR REMOVING SHARP COUNTERBORE BEVELS
(SHARPER THAN FOUR TO ONE) AND PROVIDING A 1/16 INCH RADIUS AT BEVEL
BASE TO MAKE JOINTS IN ACCORDANCE WITH REFERENCE A.
(1) TOOLS:
(A) HAND SIZE PNEUMATIC GRINDER WITH 12 TO 16 INCH
1/4 INCH DIAMETER EXTENSIONS (MADE FROM 1/4 INCH DRILL STOCK).
(B) 1/4 INCH BALL ROTARY FILE, MEDIUM COARSE, WITH
INCH SHAFT THREE INCHES IN LENGTH.
(C) 1/2 INCH BALL ROTARY FILE, MEDIUM COARSE, WITH
INCH SHAFT THREE INCHES IN LENGTH.
(D) 1/2 INCH CONE GRINDING STONE (APPROXIMATELY FOU
TO ONE TAPERED CONE) WITH 1/4 INCH SHAFT 3 INCHES IN LENGTH.
(E) 1-1/4 INCH LONG, 1/4 INCH SLEEVE WITH TWO SET S
(TO COUPLE TOOLS TO EXTENSIONS).
(2) METHODS:
(A) SET MIRROR WITH MAGNETIC STAND BEYOND COUNTER-
BORE BEVEL TO BE WORKED. ILLUMINATE WORK SECTION WITH SUITABLE HIGH
INTENSITY LIGHT.
(B) USING 1/4 INCH BALL ROTARY FILE, REMOVE SHARP B
BASE AND PROVIDE RADIUSED TRANSITION FROM COUNTERBORE TO BEVEL IN
ACCORDANCE WITH REFERENCE A.
(C) USING 1/2 INCH BALL ROTARY FILE, "FAIR IN" BEVE
REQUIRED FOUR TO ONE TAPER IN ACCORDANCE WITH REFERENCE A.
(D) USING 1/2 INCH CONE GRINDING STONE DEBURR AND
SMOOTH OUT RADIUS AND BEVEL.
(3) QUALITY ASSURANCE:
(A) FABRICATE COUNTERBORE BEVEL SLOPE GAGE (WITH
FOUR TO ONE TAPER) FROM 1/8 INCH THICK SHEET METAL.
(B) USING GAGE AND MIRROR WITH MAGNETIC STAND, EN-
SURE EACH JOINT COUNTERBORE BEVEL IS TAPERED PROPERLY (FOUR TO ONE
IN ACCORDANCE WITH REFERENCE A).
(4) EXPECTED WORK RATE IS TWO FOUR INCH JOINTS PER EIGHT
HOUR PERIOD IN STEAM DRUM, 1.5 JOINTS IN WATERDRUM (WATERDRUM IS
SLOWER BECAUSE OF TIRESOME WORKING POSITION).
C. IF TAPERS 30 DEGREES OR LESS ARE FOUND, NO CORRECTIVE
ACTION IS REQUIRED. MONITOR JOINTS AT FUTURE INSPECTIONS.
D. IF BACKING RING IS LOCATED IN SUCH A MANNER AS TO PRECLUDE
ADEQUATE INSPECTION, A PORTION OF THE BACKING RING MAY BE REMOVED
HAND GRINDING TO FACILITATE INSPECTION.
E. IF JOINTS ARE ENCOUNTERED THAT ARE NOT ACCESSIBLE FOR
VISUAL INSPECTION (SUCH AS HEADER CONNECTIONS) SPECIAL EQUIPMENT
AND TECHNIQUES SUCH AS RADIOGRAPHY OR FIBEROPTICS WILL BE NECES-
SARY. IF BACKING RING INTERFERES WITH INSPECTION OF THESE JOINTS AND
CANNOT BE GROUND OUT, STUBBING OR REPLACEMENT OF TUBE MAY BE
REQUIRED.
8. NAVSSES WILL DISTRIBUTE SKETCHES AND PHOTOGRAPHS BY 1 JUNE 1987
SHOWING THE CONFIGURATION OF ACCEPTABLE AND UNACCEPTABLE TAPERS,
CRACK LOCATIONS AND TAPER MEASUREMENT TECHNIQUES.
9. ACTIVITIES PERFORMING HAND GRINDING OF TAPERS ARE ENCOURAGED
TO CONDUCT TRAINING OF PERSONNEL ON MOCK-UPS PRIOR TO GRINDING ON
A BOILER. NAVSSES WILL PUBLISH BY 15 JUNE 1987 PHOTOGRAPHS AND
SKETCHES OF TRAINING MOCK-UPS USED HERE FOR SUCH TRAINING.
10. NAVSSES WILL PUBLISH BY 1 JULY 1987 AND ADVANCE CHANGE NOTICE TO
NSTM 8010 GIVING DETAILS OF DOWNCOMER REPAIR TECHNIQUES.
THIS ADVISORY IS APPLICABLE TO ALL SHIPS LISTED IN PARAGRAPH 4 ABOVE.