ML20137M042
| ML20137M042 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 08/19/1985 |
| From: | Henger G, Keating D, Noe P INLAND STEEL CO. |
| To: | |
| Shared Package | |
| ML20137M015 | List: |
| References | |
| 20617, NUDOCS 8601280173 | |
| Download: ML20137M042 (18) | |
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, INLAND STEEL COMPANY OPERATING TECPNOLOGY DEPARTMENT I
l INRYC0 POST TENSIONING OIVISION JOSEPH M. FARLEY NUCLEAR PLANT ANCHOR HEAD INVESTIGATION l METALLURGICAL LASORATORY INVESTIGATION NO. 20617 w I
- BY
- . o D.T.KEATING METALLURGICAL ENGINEER OPERATING METALLURGY DIVISION CPERATING TEC>NOLOGY DEPARTMENT
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APPROVED: I r'
OPERATING METALLURGY DIV.
1 OPERATING TEC>m0 LOGY c
r APPROVIO: -
lbiI.,' )' /E, IM,4 'I G.W.HENGER '/
SECTION MANAGER
, OPERATING METALLURGY DIV.
OPERATING TECPNOLOGY h1280173060117 G ADOCK 05000348
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i INRYC0 POST TENSIONING O! VISION - INVESTIGATION NO. 20817 PAGE I I
TABLE OF CONTENTS PAGE NO.
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INTRODUCTION.... ......... ............. 1 i
TESTING PROCEDURES................ ..... 3 TEST RESULTS.. ... VISUAL EXAMINATION.... 5 SEN FRACTOGRAPHY...... 7 MECHANICAL PROPERTIES. 10 CHEMICAL ANALYSES. ... 12 i
MICA 0 ANALYSES......... 13 CONCLUSIONS...... ...................... 14 REFERENCES................ ............. 18 w
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v(3 C INRYCO POST TENSIONING DIVISION - INVESTIGATION NO. 20617 PAGE 1 "NTRODUCTION THE JOSEPH M. FARLEY WCLEAR PLANT - DOTHAN, ALABAMA, FOUND IWICATIONS OF CRACKING IN FIELD ANCHOR HEADS FN 025 AND FE 068.
THE INDICATIONS WERE DISCOVERED THROUGH MAGNETIC PARTICLE INSPEC-TION BY ALABAMA POWER COMPANY (APCO) DURING AN ONGOING INSPECTION OF ALL ANCHDR HEADS. ANCHOR HEAD FN 025 REVEALED A P.TTWORK OF CRACKS IN A RADIAL OR DIAGONAL DIRECTION TtstOUGH THE HDNEYCONS WEB AREA ON THE BOTTON (SHIN) FACE. CONVERSELY, ANCHDR HEAD FE 059 SHOWED ONE SMALL INDICATION BETWEEN TWO WIRE HOLES NEAR THE CENTER OF THE 6CNEYCOW8 WEB ON THE TOP ( BUTTOfe4EAD ) FACE, AN ATYPICAL FRACTURE LOCATION.
ON JULY 9, 1985 BOTH ANC>OR HEADS WERE RECEIVED AT INLAND METALLURGICAL LABORATORY TO DETERMINE THE PROBABLE CAUSE OF CRACK-ING AND FOR TESTING AND METALLURGICAL EVALUATION. IN ADDITION, EIGHT OTHER ANCHOR HEADS. HV 036, HP 014 W Ott, FE O26, FL 048, FN OST, FK 016 AND FM O28 WHICH WERE DETENSIONED AND REMOVED FROM THE CONTAINMENT VESSEL, WERE ALSO RECEIVED. THE EIGHT SELECTED ANCHOR HEADS REPRESENT DIFFERENT HEATS AND WERE SUSMITTED FOR TEST-ING AND METALLURGICAL EVALUATION ONLY. ALL EIGHT ANCHOR HEADS WERE MAGNETIC PARTICLE INSPECTED BY APCO AFTER DETENSIONING AND NO INDI-CATIONS WERE NOTED. ONE ADDITIONAL ANCHOR HEAD, TFD 24, WHICH WAS PROM THE LOT USED FOR REPLACEMENTS, WAS ALSO TESTED.
ALL OF THE SUBMITTED ANCHOR HEADS WERE OF THE FIELD ANCHOR TYPE APC WITH THE EXCEPTION OF ANCHOR HEAD TFD 24, .ALL WERE IN SERVICE APPROXIMATELY EIGHT TO TEN YEARS. REPORTEDLY, THE ANCHOR HEADS WERE FROM VERTICAL WALL TENDONS LOCATED IN THE GALLERY OF THE BASE OF BOTH CONTAINMENT VESSELS, UNITS NO.1 AND NO.2. THE EXACT LOCA-TION OF EACH ANCHOR HEAD WITHIN THE VESSELS WAS NOT PROVIDED.
O O INRYCO POST TENSIONING DIVISION - INVESTIGATION NO. 20617 PAGE 2 THE . FIELD ANCHOR HEADS ARE 4" THICK BY 9.375" DIAMETER CYLINDRICAL PARTS AND ARE SUBJECTED TO A COM81 NATION OF SHEAR, COM-PR$$$1VE AND TENSILE LDADS IN SERVICE. FIGURE 1 IS A SKETCH OF THE APPROXIMATE LAYOUT OF THE SYSTEM COMPONENTS AT THE LOWER Em 0F THE VERTICAL TENDONS. DNE 68JNDRED SEVENTY (170) 0.257" DIAMETER HOLES ARE DRILLED LONGITUDINALLY TNtOUGH THE CENTRAL HONEYCOMB AREA OF THE ANCHOR HEAD. THE STEEL WIRES OF THE TENDONS FIT TWtOUGH THE HOLES AND ARE COLD HEADED, AFTER INSTALLATION- IN THE STRUCTURE.
THE ANCHOR HEADS ARE THEN JACKED AWAY FROM THE BEARING PLATE TO STRESS (TENSION) THE TENDONS. SPLIT SHIM PLATES ARE THEN INSERTED BETWEEN THE ANCHOR HEAD AND THE BEARING PLATE TO MAINTAIN THE TENS-ILE STRESS. AFTER TENSIONING, GALVANIZED GREASE COVERS ARE PLACED OVER THE HEADS AND T H'.ATED CCutOSION PROTECTION GREASE (VISCO O 2090P WAX-E ASCD PETROLEUM MJCLEAR CASING FILLER PACKING GREASE) IS THEN PUMPED INTO THE SYSTEM FROM THE LOWER END OF THE TENDON AND CIRCULATED UNTIL A CONSTANT TEMPERATURE IS ACHIEVED. THE GREASE COMPLETELY ENCASES THE ANCHDRAGES AND TENDONS PERIDOICALLY, THE GREASE IS " TOPPED OFF" FROM THE UPPER END OF THE TENDON.
WNINALLY, THERE ARE 358 TEMONS IN EACH OF THE CONTAINMENT S1RUCTURES (UNITS No.1 AND NO.2) 0F WHICH 130 ARE VERTICAL, 135 ARE HOOP AND 93 ARE DOME, ,
THE ANCHOR HEADS ARE MACHINED FRON 10* DIAMETER HOT WORKED AND APedEALED ASTM A-322' GRADE 4140 OR 4142 ALLOY STEEL ROUNDS. THE ANCHOR HEADS WERE REPORTEDLY PRODUCED FROM STEEL PURCHASED BY WESTERN CONCRETE FROM E. M. JORGENSON, WHO PURCHASED IT FROM REPUBLIC STEEL C00FANY. THE ANCHOR HEADS WERE HEAT TREATED BY DOWNEY STEEL TREATING - DOWNEY, CALIFORNIA. TO MILITARY SPEC.
MIL-H8875 TO A HARDNESS OF HRC 40-44. HEAT TREATING CHARTS OR TEMPERATURE RECORDS WERE NOT REQUIRED AT THE TIME THE HEADS WERE MAMJFACTURED.
THIS REPORT COVERS THE ANALYSES OF ANCHOR HEADS FN 025 AM FE 050 TO DETERMINE THE PROBABLE CAUSE OF CRACKING AND THE METALLURGICAL EVALUATION OF THESE ANCHORAGES ALONG WITH ANCHORAGES HV 036, W 014, Ptl Ott, FE 026, FL 040, FN 097 FK 018, FM 028 AND TFD 24. PRIOR INLAW STEEL INVEST!GATIONS COVERING ANCHORAGE FAILURES ARE INVESTIGATIONS NO. 06775 AND 19975 DATED MAY 28, 1980 AND MARCH 27, 1985, RESPECTIVELY.
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i INRYCO POST TENSIONING DIVISION - INVESTIGATION NO. 20817 PAGE 3 t
TESTING PROCEDURES THE BASIC METALLURGICAL TESTING PROCEDURES FOR THE TESTING OF THE SUSMITTED FIELD ANCHOR HEAD SAMPLES WERE AS FOLLOWS:
- 1. EACH SAMPLE WAS DEGREASED WITH ST000 ART'S SOLVENT AND/OR TRICHLOR0 ETHYLENE.
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- 2. VISUAL EXAMINATION AND NDNDESTRUCTIVE TESTING (LIQUID DYE PENETRANT)
WERE PERFORMED, IN THE DEGREASED CON 0!TIDN, ON ALL SUSMITTED ANCHOR HEADS.
- 3. SCANNING ELECTRON MICROSCOPE (SEM) FRACTOGRAPHY WAS PERFORMED ON ALL FRACTURE FACES OF ANCHOR HEAD FN 025 AFTER THE HEAD WAS SECTIONED TO A SUITABLE SIZE. IN ADDITION, ALL OF THE TRANSVERSE
'rNSILE SPECIMEN FRACTURE FACES AND SELECTED CHARPY V-NOTCH IMPACT f*ECIMEN FRACTURE FACES WERE EXAMINED FOR FRACTURE MODES, I.E.,
WCTILE, BRITTLE (CLEAVAGE), SHEAR OR INTERGRANULAR SEPARATION (IGS).
- 4. COMPLETE CHEMICAL ANALYSES INCLUDING RESIDUAL ELEMENTS WERE OBTAINED FROM THE ANCHOR HEADS.
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- 5. MECHANICAL PROPERTIES INCLUDED THE FOLLOWING:
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BRINELL HARDNESSES WERE OSTAINED ON THE RING SURFACE AND BRINELL AND ROCKWELL (HRC) HARONESSES WERE OSTAINED ON THE RING CROSS-SECTION OF ALL ANCHOR HEADS.
B. TRANSVERSE TENSILE PROPERTIES WERE OSTAINED FROM THE RING AREA 0F EACH ANCHOR HEAD USING STANDARD .505" DIAMETER ROUND TENSILE SPECIMENS WITH 2' GAUGE LENGTHS.
THE FOLLOWING PROPERTIES WERE OSTAINED:
- 1. YIELD STRENGTH, KSI (0.2% OFFSET)
- 2. ULTIMATE TENSILE STRENGTH, KSI
- 3. TOTAL ELONGATION, % IN 2* GAUGE LENGTH
- 4. REDUCTION OF AREA, %
IN ALL CASES, IN0!VIDUAL TEST RESULTS WERE REPORTED WITH NO AVERAGING BEING DONE. DUPLICATE TESTS WERE PERFQptMED.
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O O-INRYC0 POST TENSIONING DIVISION - INVESTIGATION NO. 20617 PAGE 4 C. CHARPY V-NOTCH IMPACT PROPERTIES USING FULL SIZE IMPACT SPECIMENS WERE OSTAINED FROM THE RING AREA 0F THE ANCHOR HEADS AND WERE TESTED AT ROOM TEMPERATURE IN THE TRANSVERSE DIRECTION.
THE FOLLOWING PROPERTIES WERE OSTAINED:
- 1. ENERGY ASSORPTION, FT.-LBS.
- 2. BRITTLE FRACTURE, %
- 3. LATERAL EXPANSION, INCHES
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IN ALL CASES, INDIVIDUAL TEST RESULTS WERE REPORTED WITH NO g AVERAGING BEING DONE. TRIPLICATE TESTS WERE PERFORMED.
- 6. METALL0 GRAPHIC EXAMINATION TO EVALUATE THE MICR0 STRUCTURE (AN EVALUATION OF THE HEAT TREATMENT) AND MICR0 CLEANLINESS AS RATED ON LONGITUDINAL MICROSPECIMENS WERE OSTAINED FROM THE RING AREAS USING THE J-K RATING SYSTEM SY APPEARANCE ONLY. IN ADDITION, SELECTIVE MICROSECTIONS FROM THE HONEYCOMS AREAS WERE ALSO EXAMINED.
i THE LOCATIONS OF THE BASIC TESTING OF THE ANCHOR HEADS ARE SHOWN IN FIGURES 2A AND 25.
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INRYC0 POST TENSIONING DIVISION . INVESTIGATION NO. 20517 PAGE 5 k
TEST RESULTS VISUAL EXAMINATION ALL ANCHOR HEADS WERE' VISUALLY EXAMINED. ANCHOR HEAD FN 025 REVEALED FINE CRACKS ALONG THE CENTRAL HONEYCOMB WEB ON THE INBOARD ,
(SHIM) FACE. NO OTHER ANCHORAGES EXHIBITED CRACKS. TO EPG4ANCE VISUAL INSPECTION, LIQUID DYE PENETRANT WAS USED TO HIW4LI#ff ANY POSSIBLE CRACKS. AGAIN, INDICATIONS WERE ONLY FOUND ON ANCHOR HEAD FN 025.
REPORTEDLY, AN INDICATION OF A CRACK WAS FOUND IN ANCHOR HEAD FE 059 ACROSS TWO TENDON l')LES NEAR THE CENTER OF THE HONEYCOMB WEB DN THE OUTER ( BUTT 0le1EA ? . FACE. THE INDICATION WAS FOUND THROUGH
) MAGNETIC PARTICLE I n*ECTION SY APCO. THE SAMPLE WAS THOROUGHLY l EXAMINED BY INLAND, WITH AND WITHOUT THE AID OF A LOW POWER STERE 3.
MICROSCOPE. THE SAMPLE WAS ALSO INSPECTED THROUGH THE USE OF LIQUID
- DYE PENETRANT AND FLUORESCENT MAGNETIC PARTICLE INSPECTION WITH i
ULTRAVIOLET LIGHT. NO CRACKS COULD BE FOUND.
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) THE ANCHORAGES SHOWED VARYING DEGREES OF CORROSION PITTING ON BOTH THE SHIM AND BUTT 0pe1EAD FACES. FN 025 SHOWED A GREATER DEGREE OF PITTING THAN THE OTHER ANCHORAGES. HEAVY PITTING WAS NOTED AT SOME OF THE CRACKS ON THE SHIM FACE AS SHOWN IN FIGURES 3A AND 35.
THE CORROSION PITTING INDICATES THAT ACTIVE CORROSION HAD OCCURRED l
OR WAS OCCURRING AT SOME OF THE CRACKS.
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INRYCO POST TENSION!NG DIVISION - INVESTIGATION NO. 20817 PAGE 8 A SECTION THROUGH THE HONEYCOMB WEB CONTAINING THE CRACKS IN ANCHOR HEAD FN 025 WAS CUT OUT AND THEN SEPARATED TO REVEAL THE FRACTURE FACES. CARE WAS TAKEN IN SECTIONING FN 025 TO INCLUDE BOTH PRECRACKS (CRACKS EXISTING ON THE AS-RECEIVED ANCHOR HEAD) AND POST-CRACKS (FRESH FRACTURES RTSULTING FROM THE OPENING OF THE PRE-CRACKS IN THE NETALLURGICAL LASORATDAY). THE FRACTURE FACES, SHOWN IN FIGURES 4-8 EXHIBITED A WOODY, FIBROUS-TYPE PRECRACK FRACTURE APPEARANCE. THE POST-CRACKED AREAS OF THE WEB HAD A SMOOTHER, CRYSTALLINE 4.PPEARANCE. IN ADCITION, THE PRECRACKED FRACTURE FACES
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EXHIBITED VARYING DEGREES OF CORROSION. THE FRACTURES ADJACENT TO i
%HE SHIM FACE EXHIBITED THE GREATEST DEGREE OF CORROSION. THE FRACTURES WERE NORMAL TO THE SHIM FACE AND WERE STRAIGHT AND ALIGNED PAFALLEL TO THE ROLLING DIRECTION. IT IS NOT KNOWN IF THE FRACTURE COINCIDED WITH THE SPLIT SHIM SPACE: HOWEVER, IT IS APPARENT THAT THE FRACTURE (S) ORIGINATED AT THE SHIM FACE OF THE HEAD IN THE HONEYCOMB WER.
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INRYC0 POST TENSIONING DIVISION - INVESTIGATION NO. 20617 PAGE 7 SCAMING ELECTRON MICROSCOPY (SEM)
FRACTOGRAPHS OF FN 025 FIGURES 5-7, HAVE ACCOMPANYING DVERLAYS.
THE OVERLAYS SHOW BOTH THE POSITIONS. AT WHICH SEM ANALYSES WERE OBTAINED. I.E., THE OUTLINED AREAS, AND THE POSITIONS AT WHICH INTERGRANULAR SEPARATION (IGS) WAS NOTED, I.E., THE CROSS-MATCHED AREAS. THE OVERLAY METHOD WAS USED IN ORDER TO CLEARLY PRESENT THE SEM ANALYSES OF THE HEAD FRACTURES AND ALSO ALLOW AN UNOBSTRUCTED VIEW OF THE FRACTOGRAPHS. ~
b CRACKED ANCHOR HEAD FN 025 SCAMING ELECTRON MICROSCOPIC (SEM) ANALYSES WERE PERFORMED ON SELECTED FRACTURE FACE AREAS OF THE HONEYCOMB; REFER TO FIGURES 5-7. THE PRECRACKED FRACTURE FACE Aur M EXHIBITED PREDOMINANTLY INTERGRANULAR SEPARATION (IGS); SEE FIGURES 9-12. IGS INDICATES THAT THE FRACTURE OCCURRED WHILE THE HEAD WAS IN A PARTIALLY EMBRITTLED CONDITION. IN ADDITION, VARYING DEGREES OF CORROSION WERE NOTED ALONG THE PRECRACKED FRACTURE FACES. IN S,OME AREAS, ESPECIALLY NEAR THE SHI;A FACC, HEAVY CORROSION PRECLUDED DETERMINA-TION OF THE FRACTURE MODE. HOWEVER, FRACTURE AREAS ADJACENT TO AND/OR SURROUNDED BY CORROSION EXHIBITED IGS. THE CRACK TIPS AT THE INTERFACE BETWEEN THE PRECRACKED AND POST-CRACKED AREAS EXHIBITED A TRANSITION FROM PREDOMIN4NTLY IGS TO PREDOMINANTLY CLEAVAGE; SEE FIGURE 13. THE POST-CRACKED FRACTURE AREAS, WHICH WERE SEPARATED i WITH THE AID OF LIQUID NITROGEN, EXHIBITED PREDOMINANTLY CLEAVAGE; SEE FIGURE 14 THE WOODY FIBROUS NATURE OF THE FRACTURES WAS CAUSED BY THE PRE-FERENTI AL . ALIQWENT OF THE NOMETALLIC INCLUSIONS IN THE ROLLING DIRECTION.
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O O INRYCO POST TENSIONING DIVISION - INVESTIGATION NO. 20617 PAGE B ANCHOR HEAD FE 059 TO FURTHER EXANINE THE POSSIBILITY OF A CRACK WHICH WAS REPORTEDLY DETECTED BY APCO ON THE BUTTDPe4EAD FACE THROUGH MAGNETIC PARTICLE INSPECTION. A SECTION OF THE SAMPLE CONTAINING THE '
SUPPOSED CRACK WAS EXAMINED WITH T;tE AID OF THE SEM. NO INDICATION OF A CRACK COULD BE FOUND AT THE SURFACE.
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GENERAL COMMENT
S ON THE SEM FRACTDGRAPHY THE PRESENCE OF ICS INDICATES THAT THE. STEEL WAS IN THE EMBRITTLED CONDITION. SEVERAL FAILURE MECHANISMS SUCH AS A TEMPER EMBRITTLEMENT PHENOMENON. STRESS CORROSION CRACKING (SCC) OR HYDROGEN STRESS CRACKING (HSC) CAN RESULT !> MS OF HIGH STRENGTH STEELS.
THE PREDOMINANCE OF IGS WITHIN THE PRECRACKED FRACTURE FACES AND NOT IN THE POST-CRACKED FRACTURE FACES INDICATES AN EXTERNAL EMBRITTLING AGENT RATHER THAN A TEMPER EMBRITTLING AGENT. THE PRE-I CRACKED AND POST-CRACKED FRACTURE FACES EXHIBITED A SHARP CONTRAST IN FRACTURE MODES, WHEREAS TEMPER EMBRITTLEMENT SHOULD RESULT IN A MORE UNIFORM DISPERSION OF IGS. IN ADDITION, SEM ANALYSES WERE PER-FORMED ON THE FRACTURED TRANSVERSE TENSILE SPECIMENS OF ALL ANCHOR HEADS AND SELECTED FRACTURED TRANSVERSE IMPACT SPECIMENS. NO IGS WAS NOTED ON ANY OF THESE TEST SPECIMENS. THE LACK OF IGS ON THE TEST SPECIMENS IS ALSO AN INDICATION THAT THE EMBRITTLEMENT IS NOT TEMPER EMBRITTLEMENT AND THE EMBRITTLING AGENT IS NO LONGER PRE-SENT.
THE PRECRACKED FRACTURE FACES EXHIBITED VARYING . DEGREES OF CORROSION WITH THE AREAS OF HEAVIEST CORROSION BEING EVIDENT NEAR THE SHIM FACE OF FN 025. THE PRESENCE OF CORROSION !$ AN INDI-CATION THAT THE FRACTURES MAY BE RELATED TO AN ENVIROPMENTAL-MECHANICAL PROCESS SUCH AS SCC OR HSC. ENERGY DISPERSIVE QUALIT-ATIVE SEM X-RAY ANALYSES OF THE FRACTURE FACES SHOWED NO SIGNIFIC-ANT IDENTIFIABLE CORROSION PRODUCTS OR EMBRITTLING SPECIES.
HOWEVER, IT SHOULD BE NOTED THAT THE X-RAY UNIT IS NOT , CAPABLE OF DETECTING HYDROGEN, CARBON, NITROGEN OR OXYGEN.
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i INRYCO POST TENSIONING DIVISION - INVESTIGATION NO 20617 PAGE S HYDROGEN STRESS CRACKING OCCURS IN HIGH STRENGTH STEELS DUE TO-THE INTERACTION BETWEEN APPLIED TENSILE STRESS AND HYDROGEN DIS-SOLVED IN THE METAL LATTICE. WHILE TENSIONED, THE ANCHOR HEADS ARE SUBJECTED TO SUSTAINED TENSILE STRESSES AND ENCLOSED BY GALVANIZED GREASE COVERS. THE GREASE COVERS ARE FILLED WITH A CORROSION PRO-TECTION GREASE WHICl3 COMPLETELY ENCASES THE ANCHDR HEADS.IT IS UNLIKELY THAT REACTIONS WITH THE GREASE WOULD PRODUCE HYDROGEN.
HAD THIS BEEN THE CASE, FN 025 WHICH WAS IN SERVICE APPROXIMATELY 8-10 YEARS, WOULD HAVE FAILED SHORTLY AFTER INSTALLATION. HOWEVER, IF THE GREASE WAS CONTAMINATED WITH WATER AND ACTED AS A CONDUCTOR.
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IT IS POSSIBLE THAT A CORROSIVE REACTION BETWEEN THE WATER AND THE s STEEL ANCHOR HEAD, OR GALVANIC COUPLING BETWEEN THE GALVANIZED ZINC COATING AND THE STEEL ANCHOR HEAD COULD LIBERATE ATOMIC HYDROGEN AT THE STEEL SURFACE. SINCE A SAMPLE OF THE GREASE SURROUNDING FN 025 DURING SERVICE WAS NOT RETAINED FOR ANALYSIS, IT IS NOT KNOWN IF THE GREASE WAS CONTAMINATED WITH WATER; HOWEVER, SIGNIFICANT CORROSION PITTING WAS NOTED AT THE SURFACE OF FN 025 INDICATING AN OXIDATION-REDUCTION PROCESS HAS OCCURRED. FURTHERMORE, INLANO
] STEEL INVESTIGATION NO.' 19975 DATED MARCH, 1985, REGARD N. FAILURE ANALYSES OF JOSEPH M.
FARLEY PCWER PLANT ANCHOR HEADS Di.TERMINED THROUGH ANALYSES OF USED GREASE SAMPLES THAT THE GREAM WAS CON-TAMINATED WITH WATER, O
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O o INRYC0 POST TENSIONING DIVISION - INVESTIGATION NO. 20817 PAGE 10 MECHANICAL PROPERTIES
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THE MECHANICAL PROPERTIES ARE PRESENTED IN THE ATTACHED TABLES 1-11. BRINELL HARDNESS TESTS WERE PERFORNED ON THE TRANSVERSE RING SURFACES, AND BRINELL A,e ROCxWEtt (HRC> HARDNESS TESTS WERE PER-FORMED ON THE RING CROSS-SECTIONS TO DBTAIN HARDNESS PROFILES FOR
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EACH OF THE 11 SUBMITTED ANCHOR HEADS. THE SPECIFIED HARDNESS RANGE WAS HRC 40-44. HOWEVER, DUE TO !>MOMOGENETIES IN THE STEEL, I.E., FERRITE PATCHES, INCLUSIONS OR SEGREGATION, BRINELL HARDNESS SHOULD BE MORE REPRESENTATIVE THAN ROCKWELL HARDNESS AND IT IS RECOt#4 ENDED THAT BRINELL HARDNESS BE USED FOR FUTURE REFERENCE. IT WAS NOTED THAT THE ACTUAL ROCKWELL HARDNESSES WERE ON AVERAGE 2-3 POINTS LOWER THAN THE BRINELL HARDNESS CONVERTED TO ROCKWELL HA40-NESS VALUES. IN ACCORDANCE WITH ASTM SPECIFICATION .E-140-s3 REGARDING STAPCARD HARDNESS CONVERSION TABLES, THE-APPk0XI uTE i BRINELL HARDNESS CONVERSION FOR MtC 40-44 ARE ED9d 392-434. MITM 1 RESPECT TO ACTUAL BRINELL SURFACE HARDNESS, ANCNNLAGES FE 028, FM 028 AND TFD 24 HAD AVERAGE SURFACE HARDNESSES WHICH WERE 4 TO 40 B694 POINTS BELOW THE MINIIRJM HARDNESS. ALL OTHER ANCHORAGES HAD AVERAGE SURFACE HARONESSES WITHIN THE SPECIFIED RANGE. WITH 4
RESPECT TO ACTUAL BRINELL CROSS-SECTIONAL HARDNESS, ONLY ANCHORAGE HV 038 HAD AN AVERAGE HARDNESS ABOVE (7 3596 POINTS) THE MAXIIRAM HARDNESS. ANCHORAGES iti 019, FL 040, FE 088 FK 018 FM 028 APC TFD 24 HAD AVERAGE HARDNESS 9 TO 77 B604 POINTS BELOW THE MINIIRJM HARDNESS. HDWEVER, THIS WOULD BE EXPECTED DUE TO SLI9ff SLACK QUENCH EXPERIENCED WITH THE STEEL GRADE AND PART SECTION INVOLVED.
WITH RESPECT TO ACTUAL st0CKWELL Cross-SEC.'!ONAL HARDNESS, ANCHORAGE HV 038 HAD AN AVERAGE HARDNESS FOR THE NINE MAftDNESS POSITIONS TESTED WHICH WAS SLIGHTLY ABOVE (0.3 P8tC POINT) THE MAXIIRJM HARD-NESS. ANCNNtAGES MJ 019 FL 040, FE 089, FN 097, FK 018, FM 028 APC TFD 24 HAD AVERAGE CROSS-SECTIONAL HARONESSES WHICH WERE 0.1 TO B.8 HRC POINTS BELOW THE MINIIRJM HARDNESS, WHICH IS ALSO ASSOCIATED WITH THE SLACK QUENCH. ALL OTHER ANCHORAGES HAD AVERAGE CROSS-SECTIONAL HARDNESSES WITHIN THE SPECIFIED RANGE.
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INRYC0 POST TENSIONING DIVISION - INVESTIGATION NO. 20817 PAGE 11
.THE TENSILE PROPERTIES WERE OSTAINED FROM MACHINED .505" OIA-METER TRANSVERSE SPECIMENS WITH 2" GAUGE LENGTHS FROM THE RING AREA 0F THE HEADS. TEST 1 WAS TAKEN ADJACENT TO THE SHIM FACE AND TEST 2 WAS TAKEN APPROXIMATELY 1-1/2" AB0VE THE SHIM FACE. NO SImi!PIC-
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ANT DIFFERENCE OR TREND IN TENSILE PROPERTIES WAS NOTED BETWEEN TEST 1 AND TEST 2. HOWEVER. A WIDE RANGE OF PROPERTIES BETWEEN DIF-FERENT HEATS WAS NOTED, WHICH MIuMT BE EXPECTED WITH THE USE OF BATCH HEAT TREATING PROCESSES. THE TENSILE STRENGTH RANGED FROM.
141.1 KSI TO 204.8 KSI. THE REDUCTION IN AREA RANGED FROM 11.8% TO ~
g 38.8%, WHICH ARE CONSIDERED 0000 TO EXCELLENT.
THE IMPACT PROPERTIES WERE OSTAINED FRON TRANSVERSE FULL SIZE CHARPY V-NOTCH SPECIMENS ALONG THE SHIM FACE IN THE RING AREA 0F THE HEADS WHICH WERE TESTED AT ROOM TEMPERATURE. THE A550RSED ENERGIES ARE ALL NORMAL-FOR THE ALLOY STEEL PRODUCT IN TPE QUENCHED AND TEMPERED CONDITION.
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INRYC0 POST TENSIONING DIVISION - INVESTIGATION NO. 20617 PAGE 12 CHEMISTRY THE CHEMICAL CHECK ANALYSES OF THE ANCHOR HEADS WERE OSTAINED FROM THE OUTER RING AREAS AND ARE REPORTED IN TABLES 1-11. ALL ANCHORAGES WERE TO MEET THE CHEMICAL REQUIREMENTS OF ASTM A-322 GRADE AISI 4140 OR 4142 HOT ROLLED ALLOY STEEL BARS. THE CHEMICAL REQUIREMENTS ARE GIVEN BELOW:
t DESCRIPTION C MN P S SI MO CR ASTM A 322-52= .38/ .75/ .035 .040 .15/ .15/ .80/
GRADE 4140-4142 .45 1.00 .35 .25 1.10 PERMISSIBLE +/ .02 +/ .04 +.005 +.005 +/ .02 +/ .02 +/ .05 VARIATIONS
- SINGLE NUM8ERS ARE MAXIMUMS. THE ASTM SPECIFICATION IS IDENTICAL TO INRYC0 SPECIFICATION 1649, DATED JJLY 15, 1972 WITH THE EXCEPTION OF THE CARBON RANGE OF .40/.45% ON THE INRYC0 SPECIFICATION.
THE CHEMICAL ANALYSES OF THE HEADS ARE IN LINE WITH THE ASTM SPECIFICATION. IN ADDITION, CU, NI, AL, N, 02, AS, TI, B, CS, V, SN AND $5 CHECKS ARE AT A SATISFACTORY RESIDUAL LEVEL. THE RESIDUAL ELEMENTS IN ALL CASES INDICATED A PROSABLE ELECTRIC FURNACE STEELMAKING ORIGIN. HEAT ANALYSES FOR THE HEATS INVOLVED IN THIS INVESTIGATION WERE NOT PROVIDED AND, THEREFORE, NO COMPARISON OF HEAT VERSES CHECK ANALYSES COULD SE MADE.
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O O INRYCO POST TENSION!NG DIVISION - INVESTIGATION NO. 20617 PAGE 13 MICR0 ANALYSES LONGITUDINAL MICROSECTIONS WERE TAKEN THRC1MM THE OUTER RING AREA AND HONEYCOMB TENDON HDLES FOR EACH ANCHORAGE. THE MICRO-CLEANLINESS WAS RATED A2-4H AND B2-4H ON THE AVERAGE, PER THE J-K RATING SYSTEM, AND RATED ON APPEARANCE ONLY. ALL ANCHORAGES CON-SISTED OF A TEMPERED MARTENSITE MICROSTRUCTURE INDICATING A QUCNCHED AND TEMPERED CONDITION. VARYING DEGREES OF WIDMANSTATTEN
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FERRITE AND LIGHT RE MANTS OF BANDING WERE NOTED IN MOST ANCHOR g HEAD MICR0 STRUCTURES. IN ADDITION, MOST ANCHORAGES SHOWED A LIGHT PARTIAL SURFACE DECARBURIZATION, USUALLY <.001" DEEP. SOME CLUSTERING OF SULFIDES WAS EVIDENT. NO CHROttIUM CARBIDES WERE NOTED.
A MICROSPECIMEN TRAVERSING.THE SUPPOSED CRACK IN ANCHOR HEAD FE 059 WAS METALLURG!CALLY PREPARED TO CONFIRM OR DENY THE EXISTENCE OF A CRACK. METALLOGRAPHIC EXAMINATION REVEALED A SEQUENCE OF MANY NONMETALLIC INCLUSIONS ADJACENT TO THE BUTTOM EAD FACE OF THE ANCHORAGE IN A LINEAR PATTERN BETWEEN TWO TENDON H0LES. ENERGY DISPERSIVE QUALITATIVE SEM X-RAY ANALYSES INDICAT'ED THAT THE INCLUSIONS CONSISTED OF VARIOUS COMPOSITIONS OF AL, CA, 90G AND FE.
i A TRANSVERSE MICROSECTION INTERSECTING THE FRACTURE FACE OF ANCHOR HEAD FN 025 WAS OBTAINED. THE FRACTURE APPEARED TO BE BRITTLE AND INTERGRAMJLAR. NO EVIDENCE OF PRIOR CRACKING WAS APPARENT.
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INRYC0 POST TENSIONING DIVISION - INVESTIGATION NO. 20817 PAGE 14 CONCLUSIONS
- 1. CRACKING OF ANCHOR HEAD FN 025 WAS DUE TO IN-SERVICE PARTIAL EMORITTLEMFNT AS INDICATED BY THE PRESENCE OF $1GNIFICANT AMOUNTS OF INTERGRANULAR SEPARATION (IGS) ON THE PRECRACKED FRACTURE FACES.
IT WAS CONCLUDED THAT THE EMBRITTLEMENT RESULTED FROM EITHER HYDROGEN-STRESS-CRACKING (HSC), STRESS CORROSION CRACKING (SCC) OA A
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CDMSINATION OF SOTH. g
- 2. THE CRACKS OF ANCHDR HEAD FN 025 ORIGINATED AT THE SHIM FACE AND PROPAGATED NORMAL TO THAT FACE IN A STRAIGHT AND PARALLEL ORIENTATION TO THE ROLLING DIRECTION.
- 3. THE ANCHORAGES EWIBITED VARYING DEGREES OF CORROSION PITTING AT THE SHIM AND BUTTOMEAD FACES INDICATING THAT ACTIVE CORROSION WAS OCCURRING OR HAD OCCURRED. FN 025 SHOWED HEAVY CORROSION PITTING AT SOME CRACKS ON THE SHIM FACE. IN ADDITION, ALL PRECRACKED FRACTURE FACES OF FN 025 SHOWED VARYING DEGREES OF CDPROSION.
4, OTHER POSSIBLE SOURCES OF IGS HAVE BEEN ELIMINATED BY THE COMSINA-TION OF SCAMING ELECTRON MICROSCOPY (SEM) AND MECHANICAL TESTING OF THE ANCHORAGES. NONE OF THE LABORATORY-CREATED FRACTURES (TENSILE SPECIMENS AND IMPACT SPECIMENS) SHOWED ANY IGS.
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- 5. ANCHOR HEAD FE 059 DID NOT CONTAIN A CRACK CONTRARY TO AN INDICATION FOUND BY ALA8AMA POWER COMPANY (APCO). HOWEVER, A SEOUENCE OF MANY NONMETALLIC INCLUSIONS ADJACENT TO THE BUTTOW EAD FACE OF THE ANCHOR HEAD IN A LINEAR PATTERN SETWEEN TWO TENDON HDLES WAS NOTED WHICH CORRESPONDED TO THE LOCATION OF THE SUPPOSED CRACK AS $1TED BY APCO.
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- O 0; INRYC0 POST TENSIONING DIVISION - INVESTIGATION NO. 20817 PAGE 15
- 8. ANCHOR HEAD HV 036 EXHIBITED A MEAN CROSS-SECTIONAL ACTUAL HRC HARDNESS A80VE THE SPECIFIED HARONESS RANGE, AND ANCHORAGES F4J 019 FL 049, FE 059, FN 097. FK 018, FM 028 AND TFD 24 HAD MEAN CROSS-MARONESSES BELOW THE RANGE. ALL OTHER ANCHDRAGES EXHIBITED MEAN CROSS-SECTIONAL HARONESSES WITHIN THE SPECIFIED RANGE. IT SHOULD BE NOTED THAT LOWER HARDNESS WOULD BE BENEFICIAL IN REDUCING THE SUSCEPTIBILITY TOWARD HSC OR SCC. THE STRENGTHS AND DUCTILITIES I APPEARED NORMAL FOR THE STEEL ALLOY GRADE AND CONDITION AND WERE CONSISTENT WITH THE HARDNESSES.
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- 7. ALL ANCHORAGES MET THE CHEMICAL REQUIREMENTS OF THE ASTM AND INRYC0 SPECIFICATIONS. ALL RESIDUAL ELEMENTS WERE AT ACCEPTABLE LEVELS.
.8. THE MICR0 STRUCTURES AND MICROCLEANLINESSES OF THE SANPLES WERE AS EXPECTED FOR THE STEEL GRADE AND CONDITION.
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O O INRYC0 DOST TENS 10NING DIVISION - INVESTIGATION NO. 20817 PAGE 18 LIST OF REFERENCES *
- 1. INRYC0 BROCt4JRE ON POST TENSIONING SYSTEMS FOR CONTAlletENT SUILDINGS.
- 2. INRYC0 MATERIAL SPECIFICATION 1849 DATED JULY 15, 1972. ,
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- 3. ASTM SPECIFICATION A 322-84A (1970).
- 4. INRYC0 MATERIAL $PECIFICATION 1322-40, " POST TENSIONING ANCHOR HEAD," 0ATED JUNE 24, 1980.
- 5. INRYC0 MATERIAL SPECIFICATION 1001-40, " GUIDE FOR PREPARATION AND CERTIFICATION OF TEST INFORMATION," DATED JUNE 24, 1980.
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- 6. PRIVATE CORRESPON0ENCE WITH H. HENORICKSON OF INRYC0 JULY 10, 1985 TO DATE.
- 7. ASM METALS HAND 800K. STH EDITION, VOL. 10 " FAILURE ANALYSIS AND PREVENTION," 1975.
- 9. AIME CONFERENCE PROCEEDINGS, " ADVANCED TEC>NIQUES FOR CHARACTERIZING HYDROGEN IN METALS," 1981.
- 10. ELECTROCHEMICAL SOCIETY, " STRESS CORROSION CRACKING AND EMBRITTLEMENT," 1958.
- 11. UOtM M. WEST, " BASIC CORROSION AND OXIDATION," 1980.
- 12. INLAND STEEL METALLURGICAL LABORATORY INVESTIGATION NO. 19975 FINAL REPORT DATED MARCH 27, 1985.
- THE AROVE REFERENCES ARE NOT'F00TNOTED IN THE REPORT.
DTK:CMB ATTAC>mENTS .
PHOTOGRAPHS 1
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