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Category:GENERAL EXTERNAL TECHNICAL REPORTS
MONTHYEARML20069F0001994-01-24024 January 1994 Vols 1-4 to Shoreham Decommissioning Project Termination Survey Final Rept ML20045C8881993-06-0808 June 1993 Vols 1 & 2 to Refueling Jib Crane 1T31-CRN-008A Incident Root Cause Analysis. W/One Oversize Encl ML20128P6451993-02-28028 February 1993 Snps Decommissioning Project Termination Survey Final Rept for Steam Turbine Sys (N31) ML20128P7431993-02-19019 February 1993 Rev 3 to 93X027, Nuclear QA Surveillance Rept ML20099H5781992-07-31031 July 1992 Rev 4 to Shoreham Defueled Sar ML20101K5791992-06-25025 June 1992 Long Island Power Authority Shoreham Decommissioning Project,Shoreham Nuclear Power Station,Technical Rept on Water Processing & Water Mgt Activities for Reactor Pressure Vessel & Wet Cutting Station ML20082M5081991-08-26026 August 1991 Rev 3 to Shoreham Defueled Sar ML20005F2511990-01-0505 January 1990 Shoreham Nuclear Power Station Defueled Sar. ML19332G1991989-09-18018 September 1989 Rev 0 to Radiological Safety Analysis for Spent Fuel Storage & Handling. ML20245E0181989-06-19019 June 1989 QC 1989 Staffing Rept ML20153G8941988-08-31031 August 1988 Rev 1 to Shoreham Nuclear Power Station Prompt Notification Sys Rept ML20196K6311988-06-29029 June 1988 QC Div 1988 Staffing Rept ML20148A4851988-02-29029 February 1988 Shoreham Nuclear Power Station PRA W/Supplemental Containment Sys ML20214U2021987-01-31031 January 1987 Technical Rept 86.2SH Verification of IPE for Shoreham. W/ 870313 Release Memo ML20210M6001986-12-31031 December 1986 Emergency Planning Federal Involvement in Preparedness Exercise at Shoreham Nuclear Plant. Related Correspondence ML20214T6021986-12-31031 December 1986 Rev 6 to Plant Design Assessment Rept for Safety/Relief Valves & LOCA Loads, Vols 1 & 2.Proprietary Suppl Withheld (Ref 10CFR2.790) ML20210K2961986-12-31031 December 1986 Nuclear Regulation,Unique Features of Shoreham Nuclear Plant Emergency Planning. Related Correspondence ML20214U3641986-10-31031 October 1986 Shoreham Startup & Low Power Testing Operations,Special Rept:Lilco QA Audit on Training & Qualifications ML20237H6381986-07-31031 July 1986 Compliance W/10CFR50,App I ML20211P6851986-06-30030 June 1986 Implications of Chernobyl-4 Accident for Nuclear Emergency Planning for State of Ny ML20203N4171986-04-30030 April 1986 Rev 2 to Tdi Owners Group App Ii:Generic Maint Matrix & Justifications SNRC-1207, Vols 1 & 2 of Colt Emergency Diesel Generator Info to Be Incorporated in Fsar. W/11 Oversize Drawings1985-11-30030 November 1985 Vols 1 & 2 of Colt Emergency Diesel Generator Info to Be Incorporated in Fsar. W/11 Oversize Drawings ML20128N9651985-05-31031 May 1985 New York Power Pool,1985 Summer Operating Reserve, Projection & Analysis ML20111C0961984-11-20020 November 1984 Rev 1 to Long Island Lighting Co,Shoreham Nuclear Power Station,Prompt Notification Sys Design Rept ML20091Q8851984-06-30030 June 1984 Colt Diesel Generator Summary for Shoreham Nuclear Power Station - Unit 1 ML20092N6631984-06-12012 June 1984 Seismic Survivability Study for MP-45 Diesel Generators ML20091M5451984-05-31031 May 1984 Design Review of Connecting Rods for Tdi DSRV-4 Series Diesel Generators, Final Rept Prepared for Tdi Diesel Generator Owners Group ML20091M5511984-05-23023 May 1984 Investigation of Types AF & Ae Piston Skirts, Final Rept Prepared for Tdi Diesel Generator Owners Group ML20091M5201984-05-22022 May 1984 Draft Final Rept, Evaluation of Emergency Diesel Generator Crankshafts at Shoreham & Grand Gulf, Prepared for Tdi Diesel Generator Owners Group ML20084E5421984-04-30030 April 1984 Emergency Diesel Generator Engine & Auxiliary Module Wiring & Termination Qualification to IEEE-383-1974 ML20087L3511984-03-31031 March 1984 Emergency Diesel Generator Air Start Valve Capscrew Dimension & Stress Analysis, Prepared for Transamerica Delaval,Inc (Tdi) Diesel Generator Owners Group ML20081C4721984-03-12012 March 1984 Design Review of Connecting Rod Bearing Shells for Transamerica Delaval Enterprise Engines ML20087L2851984-02-27027 February 1984 Control Bldg Category I Equipment Balance-of-Plant Qualification Level, Monthly Status Rept ML20086S2221984-02-27027 February 1984 Investigation of Types AF & Ae Piston Skirts ML20080U3971984-02-10010 February 1984 Rept on Special Lifting Devices ML20083F6511983-12-15015 December 1983 Analysis of Replacement Connecting Rod Bearings Emergency Diesel Generators,Fatigue Life Prediction,Shoreham Nuclear Power Station ML20083C6681983-12-0808 December 1983 Metallurgical Analysis of Cracked Piston Skirts from Emergency Diesel Generators,Shoreham Nuclear Power Station ML20081C1571983-10-20020 October 1983 Diesel Generator Status Rept ML20112J2501983-08-31031 August 1983 Critique of Hudson Inst/Lilco Defense of Shoreham Economics. Related Info Encl ML20082D8831983-08-30030 August 1983 Suppression Pool Local-to-Bulk Temp Difference,Shoreham Nuclear Power Station - Unit 1 ML20112J2981983-08-30030 August 1983 Lilco/Hudson Inst Rept on Shoreham:Analysis of Errors Re Property Taxes & Employment. Related Info Encl ML20081L6891983-08-29029 August 1983 Excerpt from Draft FSAR Section 5.2.8, Inservice Insp Program, & Section 5.2.8.1 Provisions for Access to Rcpb ML20085D8921983-07-26026 July 1983 Books 1-3 of Independent Design Review for Shoreham Nuclear Power Station, Final Technical Rept ML20072J9521983-06-30030 June 1983 Independent Design Review for Shoreham Nuclear Power Station, Executive Summary of Final Rept ML20058N6071983-06-30030 June 1983 Environ Qualification Rept for Class 1E Equipment for Shoreham Nuclear Power Station Unit 1 Lilco ML20072K0141983-06-27027 June 1983 Rev 1 to Independent Design Review,Shoreham Nuclear Power Plant ML20076M0861983-06-27027 June 1983 Rev 5 to Environ Qualification Rept for Class IE Equipment for Shoreham Nuclear Power Station Unit 1 ML20072F2401983-06-22022 June 1983 Element-By-Element Review of Lilco Transition Module of Shoreham Nuclear Power Station Offsite Radiological Emergency Response Plan ML20079R7351983-05-31031 May 1983 Shoreham Common Sensors Failures Evaluation Rept ML20073L5911983-04-30030 April 1983 Cable Separation Analysis Rept 1994-01-24
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20140G4481997-05-0101 May 1997 Part 21 Rept Re Potential Defect in Component of Dsrv & Dsr Enterprise Standby Diesel Generator Sys.Recommends That Springs Be Inspected on Periodic Basis,Such as During Refueling Outages ML20135D8011996-11-26026 November 1996 Part 21 Rept Re Two Safety Related Valves Supplied by Velan Valve Corp Were Not in Compliance W/Originally Supplied QA Documentation.Returned Valves to Velan in May 1996 & on 961120 Velan Advised That Valves Had Been Misplaced ML20080G4691995-01-26026 January 1995 Record of Telcon W/Nrc & Licensees 950126 to Clarify Position Re Dispositioning of Exempt Sources Listed in Section 6.3.3 of Shoreham Termination Survey Final Rept Dtd Oct 1994 ML20069F0001994-01-24024 January 1994 Vols 1-4 to Shoreham Decommissioning Project Termination Survey Final Rept ML20058K3841993-12-0909 December 1993 Part 21 Rept Re Potential Defect in Component of Dsrv & Dsr Enterprise Standby DG Sys,Regarding Potential Problem W/ Subcover Assembled Atop Power Head ML20057F2261993-09-30030 September 1993 Safety Evaluation Supporting Exemption Request from Requirements of 10CFR50.54(q) for License NPF-82 ML20056C7181993-07-14014 July 1993 SE Supporting Amend 10 to License NPF-82 ML20045B3551993-06-11011 June 1993 LER 93-001-00:on 930429,refueling Jib Crane Moved in Vicinity of Spent Fuel Pool Using vendor-supplied Lifting Eye in Violation of NUREG-0612.Caused by Failure to Identify Crane as Heavy Load.Meetings held.W/930611 Ltr ML20045C8881993-06-0808 June 1993 Vols 1 & 2 to Refueling Jib Crane 1T31-CRN-008A Incident Root Cause Analysis. W/One Oversize Encl ML20044C1181993-02-28028 February 1993 Shoreham Nuclear Power Station Updated Decommissioning Plan. ML20128P6451993-02-28028 February 1993 Snps Decommissioning Project Termination Survey Final Rept for Steam Turbine Sys (N31) ML20128P7431993-02-19019 February 1993 Rev 3 to 93X027, Nuclear QA Surveillance Rept ML20127H2301993-01-15015 January 1993 Part 21 Rept Re Potential Defeat in Component of Dsrv & Dsr Enterprise Standby DG Sys.Starting Air Distributor Housing Assemblies Installed as Replacement Parts at Listed Sites ML20126B0421992-12-17017 December 1992 Final Part 21 Rept Re Potential Problem W/Steel Cylinder Heads.Initially Reported on 921125.Caused by Inadequate Cast Wall Thickness at 3/4-inch-10 Bolt Hole.Stud at Location Indicated on Encl Sketch Should Be Removed ML20125C7161992-12-0707 December 1992 Part 21 Rept Re Possibility for Malfunction of Declutching Mechanisms in SMB/SB-000 & SMB/SB/SBD-00 Actuators. Malfunction Only Occurs During Seismic Event.Balanced Levers May Be Purchased from Vendor.List of Affected Utils Encl ML20127P5861992-11-23023 November 1992 Followup to 921005 Part 21 Rept Re Potential Defect in SB/SBD-1 Housing Cover Screws.Procedure Re Replacement of SBD-1 Spring Cover Bolts Encl.All Fasteners Should Be Loosened & Removed.List of Affected Utils Encl ML20128B9641992-10-31031 October 1992 Rev 0 to Shoreham Decommissioning Project Termination Survey Plan ML20118B4391992-09-11011 September 1992 Part 21 Rept Re Degradation in Abb Type 27N Undervoltage Relays Used in Electrical Switchgear.Recommends That Users Review Applications Requiring Exposures Greater than 1E03 Rads TID W/Time Delay Function Option ML20099H5781992-07-31031 July 1992 Rev 4 to Shoreham Defueled Sar ML20114A6311992-07-28028 July 1992 Shoreham Decommissioning Plan ML20101K5791992-06-25025 June 1992 Long Island Power Authority Shoreham Decommissioning Project,Shoreham Nuclear Power Station,Technical Rept on Water Processing & Water Mgt Activities for Reactor Pressure Vessel & Wet Cutting Station ML20094L1271992-03-13013 March 1992 Amend 1 to Part 21 Rept 159 Re Potential Defect in Power Cylinder Liner.Initially Reported on 920115.Caused by Liner/ Block Fit & Localized Matl Microstructure.All Drawings & Specs Revised to Address Matl Design Requirements ML20082M5081991-08-26026 August 1991 Rev 3 to Shoreham Defueled Sar PM-91-125, Monthly Operating Rept for Jul 1991 for Shoreham Nuclear Power Station1991-07-31031 July 1991 Monthly Operating Rept for Jul 1991 for Shoreham Nuclear Power Station PM-91-112, Monthly Operating Rept for Jun 1991 for Shoreham Nuclear Power Station1991-06-30030 June 1991 Monthly Operating Rept for Jun 1991 for Shoreham Nuclear Power Station PM-91-075, Monthly Operating Rept for Apr 1991 for Shoreham Nuclear Power Station1991-04-30030 April 1991 Monthly Operating Rept for Apr 1991 for Shoreham Nuclear Power Station ML20024G7171991-04-22022 April 1991 LER 91-001-00:on 910324,RB Normal Ventilation Sys (Rbnvs) Outboard Exhaust Valve Closed for No Apparent Reason.Cause Inconclusive.Sys Restored to Normal Lineup & Rbnvs Outboard Valve Will Be Stroked on Routine basis.W/910422 Ltr SNRC-1806, Revised Pages 2 & 6 to Encl a of 10CFR50.59 Annual Rept for 19901991-04-15015 April 1991 Revised Pages 2 & 6 to Encl a of 10CFR50.59 Annual Rept for 1990 PM-91-058, Monthly Operating Rept for Mar 1991 for Shoreham Nuclear Power Station1991-03-31031 March 1991 Monthly Operating Rept for Mar 1991 for Shoreham Nuclear Power Station PM-91-037, Monthly Operating Rept for Feb 1991 for Shoreham Nuclear Power Station1991-02-28028 February 1991 Monthly Operating Rept for Feb 1991 for Shoreham Nuclear Power Station PM-91-016, Monthly Operating Rept for Jan 1991 for Shoreham Nuclear Power Station1991-01-31031 January 1991 Monthly Operating Rept for Jan 1991 for Shoreham Nuclear Power Station SNRC-1797, 10CFR 50.59 Annual Rept of Facility Changes,Procedure Changes,Tests & Experiments for Jan-Dec 19901990-12-31031 December 1990 10CFR 50.59 Annual Rept of Facility Changes,Procedure Changes,Tests & Experiments for Jan-Dec 1990 SNRC-1794, Shoreham Nuclear Power Station Annual Operating Rept,19901990-12-31031 December 1990 Shoreham Nuclear Power Station Annual Operating Rept,1990 SNRC-1799, Lilco 1990 Annual Rept1990-12-31031 December 1990 Lilco 1990 Annual Rept ML20069Q3901990-12-31031 December 1990 Shoreham Nuclear Power Station Decommissioning Plan. (Filed in Category P) ML20028H0231990-09-28028 September 1990 LER 90-007-00:on 900907,unplanned Actuation of ESF Sys Occurred During I&C Surveillance Test.Caused by Inadequate procedure.SP44.650.16 Revised to Require That Leads Lifted & Individually separated.W/900928 Ltr ML20056A2001990-07-31031 July 1990 Safety Evaluation Supporting Amend 6 to License NPF-82 PM-90-097, Monthly Operating Rept for June 1990 for Shoreham Nuclear Power Station1990-06-30030 June 1990 Monthly Operating Rept for June 1990 for Shoreham Nuclear Power Station ML20055E3911990-06-25025 June 1990 Safety Evaluation Supporting Amend 5 to License NPF-82 PM-90-083, Monthly Operating Rept for May 1990 for Shoreham Nuclear Power Station1990-05-31031 May 1990 Monthly Operating Rept for May 1990 for Shoreham Nuclear Power Station 05000322/LER-1988-0151990-05-16016 May 1990 LER 88-015-02:on 880916,seismic Monitoring Instrumentation, Including Peak Acceleration Recorders,Removed from Svc for More than 30 Days Due to Corrosion on Scratch Plates.Cover Gasket Replaced & Thermal Barrier Mount to Be Installed 05000322/LER-1986-0391990-05-16016 May 1990 LER 86-039-01:on 861006,unplanned Initiation of Reactor Bldg Standby Ventilation Sys Occurred W/All Rods Inserted in Core.Caused by Faulty Design of Retaining Device.Warning Signs Attached to Valve Actuator & Valve Mod Initiated 05000322/LER-1986-0321990-05-16016 May 1990 LER 86-032-01:on 860728,RWCU Isolated on High Differential Flow Sensed by Steam Leak Detection Sys While Placing Filter Demineralizers in Operation.Cause Not Determined. Operating Procedures Revised to Monitor RWCU Sys 05000322/LER-1987-0091990-05-16016 May 1990 LER 87-009-01:on 870203,full Reactor Trip Occurred Due to Perturbation in Ref Leg.Caused by Spurious Low Level Reactor Pressure Vessel Water Level Signal.Existing Level & Pressure Transmitters Replaced W/Newer Models 05000322/LER-1987-0221990-05-16016 May 1990 LER 87-022-01:on 870604,HPCI Test Valve to Condensate Storage Tank,Globe Valve & Hpci/Rcic Test Valve to Condensate Storage Tank Failed to Close Against Sys Operating Pressure.Disc of motor-operated Valve 37 Modified 05000322/LER-1989-0051990-05-16016 May 1990 LER 89-005-01:on 890321,results of Local Leak Rate Test of Core Spray Suction Valve a Determined That Leakage,When Combined W/All Type B & C Penetration Leakages,Exceeded Tech Spec Limit.Caused by Normal Valve Degradation 05000322/LER-1989-0031990-05-16016 May 1990 LER 89-003-01:on 890310,emergency Diesel Generator (EDG) 102 Manually Shutdown During 18-month Surveillance Test Due to Failure of EDG Output Breaker.Cause Not Determined. Replacement Breaker Installed in Cubicle 102-8 05000322/LER-1985-0591990-05-16016 May 1990 LER 85-059-01:on 851219,half Reactor Trip,Full NSSS Shutoff Sys Isolation & Reactor Bldg Standby Ventilation Sys Initiation Occurred Due to Loss of Power to Reactor Protection Sys Bus B.Assembly Breaker Reset 05000322/LER-1987-0351990-05-16016 May 1990 LER 87-035-02:on 871221,880106 & 0330,high Energy Line Break Logic Isolations of RWCU & Main Steam Line Drain Valves Occurred.Caused by Problems W/Temp Monitoring Units. Grounding Scheme Changed & Transformers Rewired 05000322/LER-1988-0031990-05-16016 May 1990 LER 88-003-01:on 880322,unplanned Automatic Initiation of Reactor Bldg Standby Ventilation Sys Side a Occurred During Deenergization of Relay.Caused by Close Placement of Relay Terminals.Wiring Inside Electrical Panels Reworked 1997-05-01
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Failure f Analvsis j- ENGINEERING AND METAaVRGICAL CONSULTANTS FaAA-83-11-13 2225 EAST BAY $HORE ROAD,PO BOX 51470.
PALO ALTO.CAUFORNIA 943031415)856-9400 TELEX 704216 M&T3D/7396 4
4 METALLURGICAL ANALYSIS OF CRACKED PISTON SKIRTS FROM EMERGENCY DIESEL GENERATORS SHOREHAM NUCLEAR POWER STATION Prepared by Failure Analysis Associates i
December 8, 1983 8312230237 831209 gDRADOCK 05000322 PDR PALO ALTO + LOS ANGELES
I StMIARY Three piston skirts from the emergency diesel generators (EDG) at Shoreham Nuclear Power Station (SNPS) were found to have fatigue cracks in eleven of the twelve piston skirt bosses. None of the cracks had grown to failure. The chemistry and microstructures appeared consistent with typical ductile iron properties. Skirt Brinell hardness values were within the specifications attributed to the manufacturer.
INTRODUCTION This is a preliminary report on the metallurgical analysis of the cracked pis-ton skirts discovered in the emergency diesel generator engines at SNPS. A subsequent report, to be issued on or about December 16, 1983, will include photographs and documentation of the metallurgical and stress analysis of the ski rts.
In view of reported failures of the piston crown-to-s ki rt attachments in Transamerica Delaval Inc. (TDI) Enterprise engines, nondestructive inspection and analysis of the SNPS pistons were initiated. Initially, dye penetrant in-spection revealed linear indications near the stud attachment boss region in several piston skirts. Subsequently, all SNPS piston skirts were inspected, and linear indications were observed in all but one skirt, which proved to be 4
a later design designated as AN by TDI. With this one exceptio1, the piston skirts were of the type designated as AF, factory modified according to 10 CFR Part 21, issued on November 5, 1981. This modification, performed late in 1981 by TDI, consisted ,f spot facing each of four bosses through which studs extended to secure the separate piston crown to the skirt and replacing the originally supplied spherical washer set with two stacks of Belleville washers. The spot facing reduced the height of the stud attachment bosses from 2 inches to approximately 1/ 4 inch. The type AN skirt embodies essen-
, tially the same geometry in the casting as in the factory-modified AF skirt. ,
All SNPS piston skirts were manufactured to ASTM Specification A536-65 for ductile cast iron. According to TDI, the AF skirts were normalized and tem-pered. They were austenitized at 1700 F - 1750 F for 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> then cooled in 4
ambient air. They were subsequently tempered at 1050 F for 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> followed by cooling in ambient air.
Fadure Assocates
\
Three of the skirts identified as having potential cracks were shipped to Failure Analysis Associates (FaAA) for confirmation and analysis of the cause of these cracks. These piston skirts have been designated 1, 2, and 3. The h
number 1 skirt was removed from the number 4 cylinder of EDG #101. The second piston skirt is from the number 6 cylinder of EDG #102. The number 3 piston skirt is from the number 7 cylinder of EDG #103.
VISUAL The three AF-type pistons were examined by eddy current to confirm the pres-ence of cracks, and it was found that eleven of the twelve bosses contained one or two cracks. The cracks appeared on the inside of the piston, in the vertical ridges remaining after spot facing of tne bosses. Cracks were sub-sequently saw-cut and fractured out of all three pisten skirts. Four linear indications, revealed by dye penetrant testing, were all opened by fracturing and proved to be pre-existing cracks. The cracks were similarly located at the base of the ridges and ranged from 0.3-inch deep by 0.9-inch long to 0.2-inch deep by 0.3-inch long.
These pre-existent cracks appeared to be fatigue cracks. Some of them had faint beach marks. In addition, evidence of ductile dimples or cleavage was not observed in the flat fatigue crack region. The origin was impossible to locate for three of the cracks. However, one crack appeared to have its origin at the tip of the ridge that remained after the bosses had been spot faced. Freshly overloaded portions of the fractures, produced in opening the cracks, were rougher than the smooth, pre-existing cracks. A notable feature, visible using a lower power stereomicroscope, was the many graphite nodules intersected by the fracture surface. These nodules were smoothly fractured in the fatigue cracked areas but were more disturbed in the fresh overloaded regions of the fractures.
On several of the fractures, black, included material was apparent near as-cast surfaces. This appears to have been organic binder that has been incorporated from the core. This incl 'ded material does occur using typical foundry practices. However, these areas in the current piston skirts are deeper than those typically observed in similar castings. The included material did not appear to significantly affect the fatigue crack initiation or growth in the four cracks broken open.
Falute Assoutes
5 ELECTRON MICROSCOPY Cracks from each piston skirt were examined using a scanning electron micro-scope. The character of fractographic features varied with location on the fatigue crack surfaces. Locations nearer the crack origin were rubbed and damaged more than regions nearer the crack front. Near the crack tip on two fractures, i.e., in the fatigue region most recently formed, areas containing i
fatigue striations were observed. Although these striations were not observed on each specimen or in other areas on the crack surface, similar features were observed but without distinct fatigue striations. Worn or abraded features, such as those observed here, are typical of steel fatigue crack surfaces which have resulted from cycling between tension and compression.
These pre-existing flaws are clearly fatigue cracks. First, striations and rubbed fatigue areas were present over the entire crack surface. Second, no evidence of ductile dimples was observed between the graphite nodules. This strongly suggests that the maximum cyclic stress was below the ultimate ten-sile strength. In addition, it also suggests that major overloads were not responsible for crack extension. Finally, no cleavage was observed on the pre-existing crack surfaces. This again supports the evidence that these pre-existing flaws were the result of high cycle fatigue and not ductile or cleav-age fracture processes.
METALL0 GRAPHY The ductile cast iron was examined metallographically. Small specimens were cut out from near the fatigue-cracked bosses. These were mounted, polished, and etched to reveal the microstructure. The microstructure consisted of about 10-volume-percent graphite particles in a matrix of pearlite and fer-rite. The graphite nodules were somewhat less regular than ideal; however, this would have had no influence on the fatigue strength of the material. The matrix was about 80% pearlite and 20% ferrite; the ferrite appeared around the graphite particles, as expected. This microstructure is consistent with the heat treatment reportedly used by TDI.
Assocates
l ,
CHEMICAL COMPOSITION A sample of the number 2 AF piston skirt was removed and analyzed using vari-ous chemical analysis techniques. The reported analysis is shown in Table I.
8 TABLE I Chemistry of Cast AF Piston
+
Element Weight Percent C 3.46 Si 2.43 Mn 0.53 Cr 0.11 Ni 0.76 Mo 0.038 Mg 0.072 S 0.005 P 0.027 ,
This chemistry is typical for ductile cast iron.
HARDNESS The hardness of several pieces of these cast piston skirts was measured using the Brinell Hardness Scale. Hardness values varied from 235 to 255 BHN.
These hardness values fall within the reportedly specified hardness range of 217 to 270 BHN. These hardness values also suggest that the ultimate tensile strength of the ductile iron would be between 110 and 120 ksi. This strength correlation is consistent with the reported TDI cast iron grade of 100-70-03; where 100 represents a minimum tensile strength of 100 ksi.
CONALUSIONS The cracks in the piston skirts indicated by dye penetrant and eddy current examination proved to be fatigue cracks.
Fadute Auooates
l * .
l
)
The number of fatigue cracks in the AF-type piston skirts examined was high; almost all bosses in the samples exam-ined had fatigue cracks.
Hardness values and correlated ultimate tensile strengths are within the specifications attributed to TDI, and they are consistent with the observed composition and micro-structure.
4 Falure Assocates
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