United States Nuclear Regulatory Commission - Protecting People and the Environment


ACCESSION #: 9602220425



                           AEROFIN CORPORATION



                                 AEROFIN



Home                 STANDARD AND CUSTOM ENGINEERED              New York

Office                 HEATING AND COOLING SURFACE                Chicago

and Plant                                                          Dallas

Lynchburg                    P.O. BOX 10819                       Atlanta

Virginia                LYNCHBURG, VIRGINIA 24506



1-800-AEROFIN               February 15, 1996

Phone: 804-845-7081

Fax: 804-528-6242





CC: (with attachments)

Document Control Desk

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555



Ms. Barb Dotson

Consumers Power Company

Palisades Nuclear Plant

22780 Blue Star Memorial Highway

Covert, MI 49043-9530





Subject:       10CFR21 Report: Deviation Evaluation



Reference:     1)   Letter from Aerofin (Brian Elliott) to Consumers

               Power (Barb Dotson) dated October 4, 1995 regarding

               10CFR21 notification (copy of same telefaxed to U.S. NRC

               on October 5, 1995)



               2)   Consumers Power Purchase Order G0109437



               3)   Aerofin Shop Order No. 947963



               4)   10CFR21 Report from Cardinal Industrial Products as

               transmitted to Aerofin by Consolidated Power Supply by

               letter dated February 13, 1996 (attached)



               5)   Aerofin ASME Design Report dated 11/7/94 (copies of

               original cover page and pages 26 & 27, attached)



               6)   Aerofin ASME Design Report dated 11/7/94 (copies of

               original cover page and pages 26 & 27 marked up and

               attached to show effects of reduced bolt tensile strength

               and actual maximum system operating pressure)





Ms. Barb Dotson                                            10CFR21 Report

Consumers Power Company                                            Page 2



Dear Ms. Dotson:



This letter follows up our initial notification to Consumers Power

Company and the U.S. NRC (Reference 1) which addressed 1,475 hex bolts

(5/8"-11 x 3 inches, ASME SA193, Grade B7), manufactured by Cardinal

Industrial Products and supplied to Aerofin by Consolidated Power Supply,

which were used as header cover plate bolts in the Safety Related

containment air cooler replacement cooling coils furnished by Aerofin to

Consumers Power Company (Reference 2).  These thirteen coils (twelve

coils plus one spare) were shipped to the Palisades Nuclear Plant on or

about November 16, 1994.



The bolts in question are listed as Item #16 on "as-built" drawing 

QA-R-1012 dated 11/1/94 included with the Aerofin Quality Assurance Data

Package for this equipment.  These bolts are identified by Cardinal

Industrial Products Heat No. CK256 (856 pieces, Trace Code TU2) and Heat

No. L63051 (619 pieces, Trace Code CX1).  Of the 1,475 bolts purchased by

Aerofin, 1,456 were actually used in the coils.



Enclosed is a complete copy of the 10CFR21 Report from Cardinal

Industrial Products as transmitted to Aerofin by Consolidated Power

Supply by letter dated February 13, 1996 (Reference 4) and received by

Aerofin on February 14, 1996.



Review of the Cardinal Industrial Products report conclusions reveals

that they can make no guarantees as to what percentage of bolts may

actually be substandard, but they do state that the actual tensile

strength of any substandard bolts is between 60,000 and 70,000 psi as

compared to a minimum tensile strength requirement of 125,000 psi for

ASME SA-193, Grade B7 material.  Given this information, several

conclusions can be drawn regarding the header cover plate bolts:



     o    The allowable stress for ASME SA-193, Grade B7 bolts is 25,000

          psi (reference ASME Section III, Table I-7.3) which represents

          a safety factor of five when compared to the material minimum

          tensile strength of 125,000 psi.  Bolt stresses in substandard

          bolts should be compared to a lower allowable stress.  Using an

          allowable stress equal to one-fifth of the reduced tensile

          strength is consistent with the safety factor inherent in the

          Code material mechanical properties.  This gives an allowable

          stress for substandard bolts of 12,000 to 14,000 psi.



     o    For the design pressure load and nozzle loading, the worst

          calculated stress is the tensile stress on the short side bolts

          (13,323 psi - see Reference 5).  This is within the range for

          the reduced allowable stress of 12,000 to 14,000 psi.





Ms. Barb Dotson                                            10CFR21 Report

Consumers Power Company                                            Page 3



     o    Actual maximum system operating pressure is on the order of 80

          psig which is based upon the zero flow pressure head developed

          by the system pumps.  Compared to a design pressure of 150

          psig, there is significant margin available to accommodate

          substandard bolt strength characteristics.  (See Reference 6.)



     o    The maximum calculated bolt torque corresponding to the minimum

          reduced tensile strength is 99 ft-lbs.  This is sufficient to

          seat and seal the EPDM gasketed pressure boundary.



     THEREFORE, IT IS CONCLUDED THAT NO SUBSTANTIAL SAFETY HAZARD

EXISTS

     DUE TO THE POSSIBLE PRESENCE OF ANY SUBSTANDARD BOLTS.



Based upon the conclusions of the Cardinal Industrial Products report, it

is unlikely that any of the containment air cooler replacement cooling

coils has header cover plate bolts that are entirely (or even that a

majority are) substandard.  Consequently, it is expected that the

equipment will operate satisfactorily with substandard bolts, even if

they are present, throughout the equipment's expected operating life. 

However, it certainly is recognized that Consumers Power Company may have

received an indeterminate quantity of bolts that do not meet ASME Code

specifications.  Therefore, Aerofin will provide replacement bolts for

the 1,456 (5/8"-11 x 3 inches) ASME SA193, Grade B7 bolts if Consumers

Power Company will notify Aerofin in writing within 30 days of the date

of this letter of its desire to receive replacement bolts.



By copy of this letter, we are also notifying the NRC of this evaluation

and thereby have completed our reporting obligations as required by

10CFR21.



If you have any questions or require any additional information at this

time, please contact me at 804-528-6210 (telephone) or 804-528-6243

(telefax).



Very truly yours,





Brian C. Elliott, P.E.

Manager

Nuclear and Code Products



cc:  D. L. Corell        Aerofin President and Chief Operating Officer

     Michael D. King     Consumers Power Company Project Manager

     Dan Depuydt         Consumers Power Company Containment Cooler

                         Responsible Engineer





     Consolidated

     Power Supply



February 13, 1996



Aerofin Corporation

4621 Murray Place

Lynchburg, VA 24505





Attn:  Mr. Barry DeHart

       QA Manager



Subject:  Submittal of the Cardinal Industrial Products Final 10CFR Part

          21 Report



Dear Mr. DeHart:



Please find enclosed a complete copy of the subject document. 

Consolidated Power Supply (CPS) received the document on 2/12/96 from

Cardinal Industrial Products, which is now known as Accutech.  CPS will

retain a copy in our Nonconformance file, which is being closed based on

issuance of this correspondence.  As all CPS customers affected by the

report have been notified, as well as the Nuclear Regulatory Commission,

no further actions by CPS are deemed necessary at this time regarding the

questionable fasteners.



CPS and Aerofin personnel have had discussions concerning replacement of

the fasteners (1475 each, 5/8" - 11 X 3" SA193 B7 hex bolts) that were

supplied by CPS against Aerofin Purchase Order 13822.  It has been

conveyed that these fasteners were used in a component manufactured by

Aerofin that was supplied to Consumers Power.  If replacement fasteners

will be required, it is suggested that Aerofin obtain written

correspondence to this affect from the applicable licensee, including

written correspondence from Aerofin indicating the same.  Exact

quantities should be identified.



If there are questions or comments relative to the enclosed information

or this correspondence please contact the undersigned.



Sincerely,





Steven W. Andrews

Quality Assurance Manager



Enclosure - Cardinal Final Report (44 Pages)

cc:  H. Kerr - President, CPS, w/o; M. Mathias - Gen. Mgr., CPS, w/o;

     NCR# 95-150,w/a



   3556 Mary Taylor Road o Birmingham, Alabama 35235 o (205) 655-5515



    A Division of Consolidated Pipe & Supply Co., Inc. Birmingham, AL





DATE:     February 5, 1996



CUSTOMER:      CONSOLIDATED POWER SUPPLY

               3556 MARY TAYLOR ROAD 

               BIRMINGHAM, AL 35235



ATTENTION:     STEVE ANDREWS, MANAGER OF QUALITY ASSURANCE



SUBJECT:  10 CFR Part 21 Final Report 



Dear Mr. Andrews:



Attached is Cardinal Industrial Products' final report that was submitted

to the Nuclear Regulatory Commission (NRC) as required by 10 CFR Part 21. 

This final report is being provided to you as a courtesy to assist you in

resolving this issue.



This report was submitted to the NRC on November 21, 1995.  As of this

date, the NRC has not provided a reply or correspondence.



Should you have any questions, please contact David Z. Hathcock at (702)

739-1966.





cc:  10 CFR Part 21 file





         B&G             Home Office:

Manufacturing Company    

                         3067 Unionville, Pike

                         P.O. Box 904

                         Hatfield, PA 19440-0904

                         215-822-1925



November 21, 1995                                              QAM-95-090



Document Control Desk

U.S. Nuclear Regulatory Commission

11555 Rockville Pike

Rockville, MD 20852



Reference:     Event 29257



Subject:       Final Report



On July 10, 1995, B&G Manufacturing Co., Inc. purchased the name and

certain assets from Cardinal Industrial Products, L.P., a limited

partnership formed and operated in Nevada servicing the nuclear power

industry.  B&G adopted the "Cardinal Industrial Products" name and began

its own nuclear fastener business from that same location.



Shortly after July 10, 1995, B&G's new Cardinal Industrial Products was

notified of a substandard fastener which had been processed and sold by

Cardinal Industrial Products, L.P.



As a courtesy and service to customers, B&G is submitting a final report

of its investigation and analysis of the event so that customers can

evaluate the situation in light of 10 CFR Part 21 paragraph 21.21

(a)(1)(ii) and (b)(1).



Should you have any questions concerning this report, please contact the

quality assurance manager at the division, David Z Hathcock, at (702)

739-1966, or myself at (215) 822-1925, extension 338.



Sincerely yours,





William A. Edmonds

President



cc:  NCR File



Suppliers of:  Bolts - Nuts - Studs - Threaded Rods - Machined Specials



Service Centers:    6870 N. Fathom St.       10231 General Dr.

                    Portland, OR 97217       Orlando, FL 32824

                    503-286-6601             407-857-5858



                    4660 Pine Timbers        3873 W. Oquenco

                    Houston, TX 77041        Las Vegas, NV 89118

                    215-822-1925             702-739-1966





                       Investigation and Analysis

                                   of

                            Suspect Fasteners



                               Event 29257





                              Final Report



                               Prepared by

                      Cardinal Industrial Products

                 Division of B&G Manufacturing Co., Inc.



                             November, 1995





                              INTRODUCTION



On July 10, 1995, B&G Manufacturing Co., Inc. ("B&G") purchased the name

and certain other assets from Cardinal Industrial Products, L.P. ("CIP-

LP") a limited partnership formed and operated in Nevada servicing the

nuclear power industry.  B&G acquired these assets to begin its own

nuclear fastener business as a new division of B&G ("B&G-Cardinal").



Various owners have operated a nuclear fastener business under the

"Cardinal" name at West Oquendo Road in Las Vegas prior to B&G's

acquisition of assets from CIP-LP on July 10, 1995.  In this report the

term "Cardinal facility" is used to describe the general operations which

have continued at that site independently of ownership.  The reader is

advised to be aware of the nature and sequence of the ownership as this

report is reviewed.



Shortly after July 10, 1995, Duquesne Light notified B&G-Cardinal about

nonconforming Grade B7 hex capscrews, which had been processed and sold

to them by CIP-LP.  Several of the suspect fasteners were tested by B&G-

Cardinal and an independent testing laboratory and found to deviate from

SA 193, Grade B7 mechanical requirements.  Although these fasteners had

been processed, sold, and shipped by CIP-LP, B&G sent notifications of

the nonconformance to the NRC and to other purchasers of product from the

same lot.  As a result of the notifications, two other utility companies

reported to B&G-Cardinal nonconforming fasteners from the same lot and

one additional lot.



E&G initiated a comprehensive investigation to ascertain the scope and

cause of the problem, to determine corrective actions, to keep its new

customers fully informed and, as a courtesy, to be able to instruct them

to evaluate the condition in light of 10CFR Part 21 paragraph 21.21

(a)(1)(ii) and (b)(1).



Metallographic analysis of the nonconforming fasteners indicated improper

heat treatment, which prompted B&G-Cardinal to begin testing similar lots

of material from inventory that were manufactured using the same heat

treatment process.  This testing revealed additional nonconforming

product and thereby indicated the problem was not isolated to only one

lot but was related to the process.



Investigation and testing traced the problem to the heat treating furnace

at the Cardinal facility, and substandard fasteners most likely can be

isolated to eight lots of material processed since 1989.  (The

investigation could not address product processed prior to 1989 because

records were unavailable.)



Final Report 11/95                                                 Page 1





This report describes the problem, the investigation strategy, testing

and analysis, and other actions taken by B&G-Cardinal that revealed the

source of the defects to be processing deficiencies in heat treating

certain material at the Cardinal facility.



                               THE PROBLEM



Certain lots of hex capscews that were processed and shipped per ASME 

SA-193, Grade B7 out of the Cardinal facility by CIP-LP were found to

contain defective fasteners.  The problem was initially discovered by

Duquesne Light's Beaver Valley facility, which had sent several 3/8"

diameter capscrews to an outside laboratory for random verification

testing.  The results of these tests indicated some fasteners from the

lot were not in compliance with the mechanical requirements of the

specification.  Duquesne Light reported this failure to B&G-Cardinal. 

Independent test reports from the Beaver Valley facility (and later from

PG&E Diablo Canyon and Washington Public Power Supply System) suggested

the fasteners in question had not been properly heat treated.



The suspect lot of ASME SA-193 Grade B7 capscrews was manufactured at the

Cardinal facility from AISI medium carbon alloy steel.  The manufacturing

process utilized by CIP-LP was to cold form capscrews from spheroidized

annealed cold heading wire.  The fasteners were then heat treated by a

process of either normalizing, quenching, and tempering, or simply by

quenching and tempering.  Depending on the lot sizes, the heat treatment

was either performed at the Cardinal facility or by an approved outside

vendor.



                            IMMEDIATE ACTION



To verify the testing results obtained by Beaver Valley, B&G-Cardinal

performed tensile and hardness tests on capscrews, from the same lot. 

These tests were performed at the Cardinal facility's laboratory under

the direction of B&G-Cardinal's Quality Assurance Department. The

mechanical properties of several of the capscrews tested were found to

deviate from the minimum requirements of Grade B7.  This lot of material

was immediately removed from stock, marked as nonconforming, and isolated

in the nonconformance room.



Samples of both conforming and nonconforming fasteners were sent to an

outside laboratory for metallographic examination.  The examination of

the conforming fasteners indicated the fasteners had the tempered

martensite structure expected from proper heat treatment.  The

nonconforming fasteners, however, had a spheroidized structure that

indicated the heat-treated fasteners had not reached the temperature

required for the martensite structure to form.



Final Report 11/95                                                 Page 2





Because the nonconforming lot was heat treated at the Cardinal facility,

B&G-Cardinal decided to concentrate its investigation on the heat

treating equipment and process there.



                            THE INVESTIGATION



Early indications suggested that the nonconforming fasteners had never

been heat treated.  The lot in question weighed over 250 pounds and would

have been placed in several containers for ease of transport through the

Cardinal facility, so it was plausible that a lone container of fasteners

had bypassed heat treatment and was later intermingled with the rest of

lot, which had been heat treated.  B&G-Cardinal then sampled a large

number of the fasteners still in inventory from the suspect lot and

found, however, substandard fasteners with visible surface scale, which

indicated that all the fasteners, including suspect ones, had been heat

treated.



Because the fasteners definitely had been heated in the furnace, the

focus of the investigation turned to the heat treatment process and

equipment at the Cardinal facility.  Recognizing that a problem with the

heat treating facility may have affected other lots of material, the

Quality Assurance Department began sampling other lots from inventory

that had been heat treated through the furnace at the Cardinal facility.



During the investigation, B&G-Cardinal sent courtesy notifications to the

NRC and to companies which had purchased capscrews from the questionable

lot.  Within a few days of these notifications, PG&E Diablo Canyon

informed B&G-Cardinal of a substandard, 3/8" diameter capscrew that had

come from a second lot.  In addition, the inventory sampling process by

B&G-Cardinal revealed a third and fourth lot that contained substandard

fasteners of 3/8" and 5/8" diameters, respectively.  Courtesy

notifications were also sent regarding these lots.



It became apparent that the four lots found to have substandard fasteners

all entered the furnace in "large" charges held at a temperature for

"short" periods (relative to other charges performed at the Cardinal

facility).  The period in question was the duration parts were held in

the furnace ("soaked") at the specified temperature for austenitizing

just prior to lowering the basket of parts into a quench tank.  The

soaking time for A/SA 193, Grade B7 product must be long enough to allow

all parts to achieve an austenitic microstructure prior to quenching them

rapidly in a liquid medium at a controlled temperature of 125 degrees F. 

The quenching provides a rapid temperature drop that results in the

formation of a primarily martensitic structure.  After quenching, parts

should register hardness values of approximately 50 on the Rockwell C

scale and tensile strengths between 225,000 and 300,000 psi.  The parts

then undergo a tempering cycle that entails heating them to a



Final Report 11/95                                                 Page 3





1,100 degrees F minimum followed by a slow cooling process.  Tempering

reduces the tensile strength and develops ductility as required (for A/SA

193, Grade B7, a minimum tensile strength of 125,000 psi with ductility

exhibiting 16% minimum elongation and 50% minimum reduction of area).



Two primary problems can occur with the heat treating cycle.  First, the

charge may not be allowed to "soak" in the furnace long enough for all

the fasteners to reach the temperature required to achieve an austenistic

microstructure.  Second, the parts may not cool rapidly enough if the

liquid quenching medium is not circulating sufficiently enough to provide

adequate heat transfer in the required amount of time.  The lots in

question were processed in heat charges of relatively heavy weight, which

could be a potential factor in either problem.  If the charge size was

too large, some or all the parts may not have reached the required

temperature in the given time period; or the temperature of the quenching

liquid may have become too high to accomplish the required rapid cooling

by the time the liquid reached the parts at the center of the charge upon

being lowered into the quenching tank.



Heat treatment logs for charges performed at the Cardinal facility dating

back to 1989 were included in the records obtained by B&G-Cardinal from

CIP-LP.  B&G-Cardinal examined these logs, which showed since 1989 a

total of 333 charges were heat treated involving AISI 4140 medium carbon

alloy steel.  The data for each of these charges was entered into a

spreadsheet and then sorted in descending order by weight and time

(pounds per hour) with the expectation that the worst case charges

(heavier charges or shorter soak times) would appear first (See Addendum

1).  The charge with the previously identified 5/8" lot with known

substandard fasteners was at the top of the list, and the other three

3/8" lots were all within the first 13% of charges listed.  The pattern

of sorted data was as anticipated and indicated that sound metallurgical

principles were taking investigation in the proper direction.



Most of the product identified in the heat treatment log had been sold

and shipped prior to B&G's purchasing assets from CIP-LP, therefore lots

generally were not available from inventory for testing.  Thus, the

strategy of investigation was to recreate the heat treating conditions

that would produce known defects.  Test charges were planned using times,

temperatures, and weights identical to the heat charges known to have

produced defective product.  Other test charges were devised with the

purpose of determining what combinations of weight and soak times would

result in defective product.  From the heat treatment log, charges with

extreme weights relative to soaking times were identified for each

diameter of Grade B7 capscrews, and product was either manufactured or

taken from inventory to be used for the test charges.



Final Report 11/95                                                 Page 4





Over a two week period, 22 test charges were heat treated.  After each

charge, test coupons were removed from specific locations within the heat

treatment basket and were tested for hardness (See Addendum 2).  From the

results of the early test charges, the following hypotheses were formed:



     1.   Some of the fasteners in the basket were not reaching the

          required temperature in the allotted time.  This conclusion was

          based upon the location of the substandard fasteners found in

          failed test charges.  This hypothesis is supported by two

          separate metallographic examinations of substandard fasteners.



     2.   The time required for all fasteners in the charge to reach

          temperature is dependent upon charge density as well as overall

          weight.  Charge density is a function of the fastener's

          dimensions where 3/8" diameter fasteners will pack more densely

          than 5/8" diameter fasteners.



In addition to performing tests to verify the integrity of past charges,

other charges were specifically performed to verify the above hypotheses.



Because the problem appeared to relate in general to heat transfer and

not necessarily to any specific material, the investigation was broadened

to include all heat treated materials.  The heat treatment logs were

again reviewed, but without regard for material or heat treatment type

but rather simply for what appeared to be the critical indicators of

weight, time at temperature, and charge density.  No other charges were

found to have critical factors in the range which coincided with test

charge failures.



During the investigation, the possibility of a problem with the quenching

phase of the heat treating cycle was dismissed based upon metallographic

analysis.  The metallography comparisons of acceptable and substandard

fasteners taken from the same lot showed two clearly different but

identifiable microstructures.  The photomicrograph of the acceptable

fastener showed the proper tempered martensite microstructure with some

retained austenite.  The microstructure of the substandard fastener was

spheroidized carbides in a ferrite matrix, which results only when alloy

steel does not reach the austenitizing temperature.  Either

microstructure was dependent upon proper quenching.  In other words,

inadequate quenching in either case would have produce yet another

identifiable microstructure.



Final Report 11/95                                                 Page 5





                         INVESTIGATION FINDINGS



In the process of performing of 22 different quench-cycle test charges,

B&G-Cardinal was able to recreate heat treatment conditions and

substandard fasteners corresponding to the four inventory lots known to

have contained substandard fasteners.  Because these test charges

produced the expected results and thereby substantiated the hypotheses,

B&G-Cardinal ceased investigating other causes.  In addition to the test

charges that recreated known failures, other test charges produced

substandard fasteners that paralleled four additional lots of material

from the heat treatment log.  While there is no conclusive evidence that

corresponding actual production charges contained substandard fasteners,

it was likely they did, therefore, B&G decided to send courtesy

notifications to the NRC and known customers for these lots, too.  The

other 14 test charges done under the remaining worst-case conditions

produced acceptable results and therefore strongly suggests that

substandard fasteners can be isolated to the eight lots of inventory for

which simulated heat-treatment charges produced failures.



The test charges containing substandard fasteners were evaluated by

hardness testing of forty coupons taken from specific locations from

throughout the charge.  The hardness readings were documented on forms

which detail the location of each coupon (See Addendum 2).  Based upon

the map of the hardness readings, it is apparent that the bottom layer of

fasteners near the center of the basket was the last to reach temperature

in larger lots.  The primary heat transfer mode for the furnace is

radiation.  The secondary heat transfer mode is conduction.  In large

charges of densely packed fasteners, conduction becomes much more

important.  Because of the configuration of the furnace at the Cardinal

facility, the bottom center portion of the basket did not receive

significant heat through radiation.  Fasteners at the bottom layer

received their heat through conduction from the upper layers of

fasteners.  In the charges containing substandard fasteners, the time

required for the heat to reach the bottom layer of fasteners was longer

than the fasteners remained in the furnace.



This problem was not discovered earlier because the test coupons that had

been used by the Cardinal facility for tensile and hardness testing were

typically placed at the top, center spot of the charge.  Had the test

coupons been placed within the area of the charge which failed to reach

temperature because of lagging heat transfer, the defects could have been

detected during the normal testing performed on heat charges.



The furnace at the Cardinal facility takes approximately two hours to

reach the appropriate austenitizing temperature for A/SA 193, Grade B7. 

After this temperature is reached, the fasteners are allowed to "soak" at

temperature for at least one hour.  The soak time is intended to provide

even distribution of the heat.  The furnace's thermocouple used to



Final Report 11/95                                                 Page 6





register its temperature is positioned in the upper region of the furnace

(See Addendum 3).  The results of the test charges demonstrated that not

all the contents of a charge reach the indicated temperature at the same

time.  The time required for the bottom layer of fasteners to reach

temperature was affected by the weight of the charge and the charge

density.



One of the test charges that failed (#21) was 331 pounds of 3/8" x 1"

long capscrews.  This charge contained nearly 8,000 pieces and was only 2

1/2 inches deep in the basket (the basket is 37 inches long and 25 inches

wide).  Another charge of the equivalent weight (#5) passed but contained

5/8" x 2 1/2" and 5/8" x 3" long capscrews.  This charge contained just

over 1,100 fasteners and was 4 1/2 inches deep.  How densely fasteners

were packed in the charge affected the amount of heat received through

radiation as compared to conduction.  In general, the smaller the

diameter of the fasteners, the more the charge acts as a solid mass.  In

both of the above listed examples the charge was held at temperature for

one hour, but the charge that failed had 3/8" diameter fasteners that

packed more densely than the charge that passed with the larger, 5/8"

diameter fasteners.



In another example, the diameter of the test charge was held constant and

packing density was changed.  300 pounds of 3/8" x 1" long capscrews were

held at temperature for one hour and contained no bad fasteners (test

charge #19).  Another charge (#22) contained 270 pounds of 3/8" x 4"

capscrews and was also held at temperature for one hour.  The four-inch

long capscrews of this lot were carefully lined in rows when packed into

the basket (which is a common practice to prevent shank warpage).  The

tightly packed charge of four-inch long screws contained failed

fasteners.



                        INVESTIGATION CONCLUSIONS



The conclusion of this investigation is that the substandard fasteners

resulted from procedural error involving the time that heat treatment

charges were held at temperature for the given conditions, specifically

the charge's weight and density as determined by the diameter of the

products and method of packing.  According to the records left behind by

CIP-LP, the standard practice of CIP-LP for heat treating operations

referred to Military Standard MIL-H-6875.  However, the CIP-LP's standard

practice made no reference to factoring the overall weight or packing

method when determining the correct soaking time for a particular charge

in the furnace at the Cardinal facility.



The heat treatment equipment located at Cardinal facility does have

limitations.  In general, the furnace has heating elements on four sides

and on the ceiling (See Addendum 3).  This would not be a problem except

that the single thermocouple is located in the ceiling of the furnace. 

The temperature indicated on the display panel and recorded on the strip

chart



Final Report 11/95                                                 Page 7





may not reflect the temperature throughout the furnace and the charge. 

This limitation, however, could have been compensated for procedurally by

allowing charges to remain at temperature for longer periods of time.



B&G-Cardinal has been asked what the percentage of fasteners is

substandard in the suspect, and what is the strength of the substandard

fasteners.  It should be assumed that the heat treatment of any of the

suspect lots was insufficient to achieve the mechanical properties of

A/SE 193, Grade B7, and that the mechanical properties of the fasteners

from those lots are equivalent to annealed AISI 4140 material.  This

means the tensile strength is between 60,000 and 70,000 psi.  Estimating

the percentage of fasteners that are substandard in a given lot is much

more difficult.  Basing estimates upon heavy charges having five or six

layers of capscrews with as many as fifty percent of the bottom layer

being substandard suggests that the lot would contain 10 percent

defective fasteners.  However, one cannot assume that substandard

fasteners are distributed evenly throughout a total lot; defective

fasteners, for instance, could have been concentrated into one container

when packed for warehousing or shipping.  Therefore, B&G-Cardinal cannot

conclusively say what percentage of fasteners purchased by any particular

customer was substandard.



There are two other factors in connection with the heat treating

equipment at the Cardinal facility which would tend to isolate suspect

charges to the types of product and material investigated with the 22

test charges.



The first is the quenching medium, which is a polymer solution.  The

particular design of the quench tank located at the Cardinal facility

precludes the use of oil because it would be a fire hazard.  The polymer

solution is a suitable alternate for oil for many materials such as A/SA

193 Grade B7.  But a polymer solution cannot be used in the heat

treatment of very high strength materials such as A490 structural bolts,

A574 socket screws, F912 set screws, or A354 Grade BD (SAE J995 Grade 8)

because these specifications require an oil quench.  A polymer solution

is also not suitable for quenching products made from medium carbon

steels, such as A325 structural bolts, A449 Type 1 (SAE J995 Grade 5)

bolts, A194 Grade 2H nuts, A563 Grade C, D, or DH nuts, and F436 flat

washers.  Consequently, there seems no reason to believe that any of

these types of products would have undergone heat treatment at the

Cardinal facility.



Secondly, rods and studs were generally not heat treated at the Cardinal

facility because they were produced from bars which already met

applicable specifications and did not require additional heat treatment. 

In addition, the heat treatment basket could not physically accommodate

any studs or rods longer than 36 inches.



Final Report 11/95                                                 Page 8





B&G-Cardinal believes that the problem of substandard fasteners

discovered initially by Duquesne Light does not extend beyond the eight

lots of Grade B7 capscrews already identified through testing charges

based upon critical factors of weight, density, and soaking times; but

B&G-Cardinal cannot guarantee this conclusion.  Customers should evaluate

replacing any fasteners installed from these eight lots, and should

consider testing other lots if deemed necessary for further assurance.



                                 SUMMARY



Shortly after receiving notification from Duquesne Light that capscrews

sold to them by CIP-LP did not meet the specification requirements, 

B&G-Cardinal began an investigation into the cause and scope of the

problem.  During this investigation, a detailed review of records was

performed as well as a duplication of past heat treatment charges. 

During the investigation, B&G-Cardinal recreated the heat treating

conditions of suspect lots and through test charges successfully

duplicated the failures in four lots of material known to contain

substandard fasteners; additional test charges produced four more lots

with substandard fasteners, which may indicate that corresponding lots in

the field may also have substandard fasteners.



The cause of the problem was determined to be procedural error.  As a

courtesy, B&G-Cardinal has notified the NRC and the companies that

purchased capscrews from lots containing suspect material.



B&G-Cardinal has discontinued using the heat treatment equipment at the

Cardinal facility until such time that satisfactory modifications are

made to both the hardware and procedures governing the heat treating

operation.



Corrective action to preclude recurrence include, but are not limited to:



     1.   Revising or adding procedures to address minimum soak times,

          basket loading procedures, and placement of test specimens;

          upgrading training programs for operators of the furnace.



     2.   Adding a second thermocouple to the furnace located at the

          bottom-center of the furnace near the parts basket (where heat

          transfer can lag behind other sections of the furnace,

          depending on weight and density).



     3.   Adding a view port to the furnace so that the operator can

          observe the charge during the heat treatment.



Final Report 11/95                                                 Page 9





     4.   Considering overhauling or replacing the furnace if other

          corrective actions are insufficient.



                                ADDENDUMS



     1.   Sorted Heat Treatment Data Showing Heavy Charges

     2.   Test Charge Results

     3.   Heat Treatment Equipment at the Cardinal Facility



Final Report 11/95                                                Page 10





Table "Heat Treatment Log Charge Data - Sorted by Pounds per Hour",

Addendum 1 Pages 1 thru 7, omitted.



Note (1) Charge 2572 was determined to be good based primarily upon data

from charge 12. In addition to test charge 12, test charge 22 was also

considered as a reference.  Although test charge 22 was considered to

contain non-conforming parts, it very nearly passed.  Test charge 22 was

referenced because the diameter and length of the parts were similar to

charge 2572.  The additional 30 minutes charge 2572 was held at

temperature, compared to test charge 22, provides adequate assurance that

this was a good charge.





Table "Test Charge Results" omitted.



The remaining addendum contains analyses for the above 22 test charges

except for charges numbered 1, 2, and 5, which were either superceded or

re-performed.



NOTE: To maintain consistency throughout testing, the Rockwell C scale

was used to record all hardness values since readings are valid for the

entire scale.  In normal practice, hardness values would be expressed

using a different scale if Rockwell C readings were below 20.



                                                               Addendum 2

                                                                   Page 1





Table "As Quenched Heat Treat Charge Analysis", Addendum 2 Pages 2 thru

20, omitted.





                        Heat Treatment Equipment



General:  The heat treatment equipment at the Cardinal facility consists

of a basic electric furnace, a separate quench tank containing a polymer

solution, as well as several instrumentation and control systems.



Furnace:  The furnace has two main components, the base and the door. 

The base is supported by a steel structure at a height of 4 1/2 feet

above the foundation (just lower than the top of the adjacent quench

tank).  The door is supported by the same structure, and moves vertically

to allow for insertion and removal of the parts basket.  The door

operates hydraulically with a total travel of approximately 30 inches.  A

rack supported by bricks rests in the center of the base.  The basket

containing the parts being heat treated is placed on the rack.  Both the

rack and the basket are made from Inconel.  The furnace door houses the

heating elements and the thermocouple.  There are eleven rows of heating

elements; two on each side and three across the ceiling.  Side views of

the furnace door and base are shown below as Figures 1 and 2.  Figure 1

is the view from the quench tank.  Figure 2 is the view from the side

perpendicular to the quench tank.



Figure 1 "Furnace Side View Facing Quench Tank" omitted.



                                                               Addendum 3

                                                                   Page 1





Figure 2 "Furnace Side View" omitted.





Figure 3 is a side view of the furnace with the oven door in the closed

position.  With the oven door closed, there is approximately 2 1/2 inches

of clearance between the top of the basket and the upper heating

elements.  The thermocouple protrudes eight inches from the ceiling and

extends into the basket approximately two inches.



Figure 3 "Furnace Door Closed" omitted.



                                                               Addendum 3

                                                                   Page 2





Figure 4 is a top view (and side view) of the base with the bottom of the

figure facing the quench tank.  The bricks used to support the rack are

arranged in a symmetrical pattern as shown.



Figure 4 "Top View of Base" omitted.





Figure 5 is a top view with the same perspective as Figure 4.  This view

shows the part's basket placed an the rack and a cutaway view of the door

showing the clearance between the basket and the side heating elements.



Figure 5 "Top View of Base with Basket" omitted.



                                                               Addendum 3

                                                                   Page 3





Figure 6 is a top view of the door as viewed from the base looking up. 

The right side of the drawing faced the quench tank.  This view shows the

upper three rows of heating elements and the location of the

thermocouple.



Figure 6 "Top View of Door" omitted.





Quench Tank: The quench tank is located adjacent to the furnace.  The

tank contains 2,390 gallons of a polymer based quenchant.  The polymer is

suspended in water and precipitates out onto the hot parts when they are

lowered into the tank.  This provides an insulative layer which controls

the rate of temperature drop.  The polymer returns into solution as the

parts cool.  The polymer is a suitable replacement for oil as a

quenchant, except for specifications which specifically state parts must

be quenched in oil.  The quenchant is circulated by an agitator assembly

located at the bottom of the tank.  The agitator ensures a continuous

flow of quenchant through the parts basket during the quench.  The

polymer quenchant in maintained at approximately 125 degrees F for

quenching A/SA 193 Grade B7 products.



Instrumentation and Controls: The signal from the thermocouple is sent to

a control panel which automatically maintains the furnace temperature by

controlling the power to the heating elements.  The temperature is

maintained within a tolerance of +/-15 degrees F.  The temperature signal

also feeds a strip chart recorder which plots temperature against time.



Other.  The oven door, basket crane, and agitators are all operated by

individual hydraulic systems.



                                                               Addendum 3

                                                                   Page 4





                              DESIGN REPORT



                  ASME BOILER AND PRESSURE VESSEL CODE



          SECTION III, DIVISION 1, CLASS 3, SUBSECTIONS ND & NF



                         1989 EDITION NC ADDENDA





                     BUYER: CONSUMERS POWER COMPANY



                         PALISADES NUCLEAR PLANT



                     PURCHASE ORDER NUMBER  G0109437





                          AEROFIN TYPE R COILS



                      AEROFIN SHOP ORDER  CR-947963

                                          Items 001 thru 013





                       SPECIFICATION M-60A, REV. A





                              page 1 of 39



                        AEROFIN CALCULATION FILE

                          CA-529-546     Rev 4





AEROFIN CORPORATION           PREPARED BY:

4621 MURRAY PLACE                            KIM W. LIENBERGER

PO BOX 10819                                 PROJECT ENGINEER

LYNCHBURG, VA 24506

                              APPROVED BY:

                                             GARY CARROLL

                                             VICE PRESIDENT

                                             ENGINEERING





ASME SECTION III, SUBSECTION ND DESIGN REPORT          PAGE 26 OF 39



AEROFIN CALCULATION FILE CA - 529 - 546   REV. 1





HEADER BOLT ANALYSIS



Bolt Material:  ASME SA-193 Gr. B7   5/8 in. Diameter.

Tensile Stress area = .226 in**2

Allowable stress = 25000 psi [ASME Section III Table I-7.3]

Minimum ultimate tensile strength = 125000 psi [Table I-7.3]



The header bolts are subjected to loads due to pressure, gasket seating,

and nozzle loads.  These loads are summed to find the worst case stress

on any of the bolts.



From the specification, Nozzle Forces (lbs) and Moments (in-lbs) are Fx=

1200  Fy= 1200  Fz= 1200  Mx=  7200  My= 7200  Mz= 7200





PRESSURE LOAD   Ref. ASME Sec. III, Appendix XI-3220



Pforce = Force / blot due to pressure

Pforce = pressure * area / number of bolts

Pforce = 150 * (18.5 * 51.0) / 56 = 2,527.3 lbs/Bolt



GASKET LOAD   Ref. ASME Sec. III, Appendix XI-3221.1



Effective gasket seating width:  Ref. ASME Section III Table XI-3221.1-2



     For perimeter gasket bo1 = (W + T)/2 = (1.5 + .125) / 2 = .8125

                           b1 = .5 * sqrt (bo1) = .5  * sqrt(.8125) =

                                .4507

                          bo2 = (W + N) / 4 = (.25 + .375) / 4 = .156

                           b2 = bo = .156

          Gi = Perimeter at gasket reaction

          G1 = 18.5 in.

          G2 = 51.0 in.



Gforce = Force / bolt due to gasket reaction

     Gforcei = 2 * bi * mi * pressure * Gi / number of bolts

     Gforce1 = 2 * 0.4507 * .50 * 150 * 20.0 / 56 = 24.1 lbs/bolt

     Gforce2 = 2 * 0.156  * .50 * 150 * 51.0 / 16 = 74.6 lbs/bolt

Gforce = 24.1 + 74.6 = 98.7 lbs/bolt



NOZZLE LOADS

Axial forces on bolts are induced by Fx, Fy, Fv, My, & Mv.

Bl = # of bolts on long side; Bs = # of bolts on short side

Dl & Ds = Center to center distance between bolts on long & short sides



Bl = 17, Bs = 7, Dl = 52.5, Ds = 20.0





ASME SECTION III, SUBSECTION ND DESIGN REPORT       PAGE _27_ OF _39_

AEROFIN CALCULATION FILE CA - 529 - 546  REV. 2



HEADER BOLT ANALYSIS   continued



Fl = forces on long side bolts due to Fx, Fy & Mv

Fl = (Fx / Bl) + (2 * (Mz + Fy * a) / (Bl * Ds))

Fl = (1200 / 17) + (2 * (7200 + 1200 * 9.875) / (17 * 20.5)

Fl = 180 per bolt



Fs = forces an short side bolts due to Fx, Fv & My

Fs = (Fx / Bs) + (2 * (My + Fz * a) / (Bs * Dl))

Fs = (1200 / 5) + (2 * (7200 + 1200 * 9.875) / (5 * 52.5)

Fs = 385.1 per bolt



TOTAL TENSILE STRESS



Long side tensile force per bolt = Tl = Fl + pload * gload 

                                 = 180 + 2,527.3 + 98.7 = 2806

Short side tensile force per bolt = Ts = Fs + pload + gload

                                  = 385.1 + 2,527.3 + 98.7 = 3011.1

Tensile stress = Tensile Force / Stress area

Tensile stress on long side bolts = 2806.0 / .226 = 12,416 psi

Tensile stress on short side bolts = 3011.1 / .226 = 13,323 psi

For calculations use the larger of short or long side stress

Total tensile stress = Saxial = 13, 323 psi



SHEAR STRESS



Shear stresses are induced by Mx

Shear force = Fs = 2Mx / 4*d  d = longest perpendicular distance from

                                  moment to bolts (4 corner bolts)

Shearing Force = 2 * 7,200 / 4 * 40  = 90

Shear Stress = Shear force / stress area = 90 / .226 = 399 psi



MAXIMUM BOLT TORQUE (Ref Spotts p 276)

T = 0.2 * Area * dia(major) * (0.7 * Ult strength)

T = 0.2 * 0.226 * 0.625 * (0.7 * 125000) /12 (12 converts to ft-lbs)

T = 206 ft-lbs



COMBINED TENSILE AND SHEAR STRESSES

Combined tensile and shear stresses must not exceed the ellipse equation

given in NF-3324.6(3) [1986 Code].

The 1989 Code does not address allowable shear stresses for non-welded

pressure-retaining components.  Therefore, using allowable shear stress

equation for structural components in 1989 Code NF-3324.6,

Fvb = .62 * Su / 3 = .62 * 125000 / 3 = 25,833

Ftb = Su / 2 = 125,000/2 = 62,500

(ft**2 / Ftb**2) + (fv**2 / Fvb**2) 









Page Last Reviewed/Updated Thursday, March 29, 2012