Information Notice 1992-68, Potentially Substandard Slip-On, Welding Neck, and Blind Flanges
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
September 10, 1992 NRC INFORMATION NOTICE 92-68:
POTENTIALLY SUBSTANDARD SLIP-ON, WELDING NECK,
AND BLIND FLANGES
Addressees
All holders of operating licenses or construction permits for nuclear power
reactors.
PurDose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert licensees to problems with potentially substandard slip-on, welding neck, and blind flanges. It is expected that recipients will review
this information for applicability to their facilities and consider actions, as appropriate, to avoid similar problems. However, suggestions contained in
this information notice are not NRC requirements; therefore, no specific
action or written response is required.
Description of Circumstances
On July 9, 1992, the NRC staff met with a representative of The National Board
of Boiler and Pressure Vessel Inspectors (Board) to discuss the Board's
investigation of problems associated with flanges that originated from the
People's Republic of China.
The Board has received numerous reports of
flanges marked "China" that contain cracks, inclusions, and slugged weld
repairs, and that were constructed from two pieces of material.
The suspect China flanges were sold to U.S. suppliers through several trading
companies. Three of the trading companies identified were: Billiongold
Company Limited of Hong Kong, Tain Gong Company, and Shanxi Province Overseas
Trading Corporation. The suspect flanges were marked as forgings that
complied with the requirements of the American Society for Testing and
Materials (ASTM) Standard A-105, "Specification for Forgings, Carbon Steel, for Piping Components," and the American National Standards Institute (ANSI)
Standard B16.5, "Dimensional Standards for Steel Pipe Flanges and Flanged
Fittings."
However, the suspect flanges were manufactured with ring-inserts
welded to the inside diameter of the flange and the outer surfaces were
machined.
Consequently, a visual inspection would not detect either the
welding or the two-piece construction. Other flanges were found with slugged
weld repairs to the flange hub and still others failed to meet the material
specification requirements for thermal treatment, mechanical properties, or
chemistry.
9209030274 PD P.
September 10, 1992 Discussion
The Board determined that one Chinese flange manufacturer, of the several
known factories that supply the U.S., shipped more than 110 tons of
ASTM A-105, ANSI B16, China flanges to this country.
The Board stated that
over 7,000 flanges are being removed from refineries and petro-chemical plants
as a result of failures that occurred during welding, bolting, and hydrostatic
and pre-operational testing. The Virginia Electric and Power Company informed
NRC staff that China flanges are installed in two of its fossil power plants
and others are in its warehouse.
At the time of discussion, Virginia Power
had not determined whether any suspect China flanges are installed in its
nuclear power plants.
The NRC does not have evidence that any suspect China flanges have been
installed in U.S. nuclear power plants.
However, specific examples and
discussions of the problems are attached for information.
A potentially substandard "China" flange can pass between two or more
distributors before reaching the end-user facility. A nuclear power plant
could buy a commercial grade China flange from a distributor to dedicate the
flange for safety-related use, or safety-related components or subassemblies
that contain China flanges could be supplied by licensee-approved
manufacturers or fabricators.
Establishing and verifying procedures to trace
procured equipment and material to the original manufacturer or mill is an
important prerequisite to inspecting and testing during the dedication
process.
It is possible for a licensee to install potentially substandard or
defective equipment or material if it does not adequately verify that the
product can be traced to the original manufacturer.
This information notice requires no specific action or written response. If
you have any questions about this matter, please contact the technical contact
listed below, one of the Board representatives listed on the attachments, or
the appropriate Nuclear Reactor Regulation (NRR) project manager.
I-
Cha4rles E.
ROssi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical contact:
Steven M. Matthews, NRR
(301) 504-3191 Attachments:
1. 1992 Board article, "Failure Analysis of a Slip-On Flange."
2. Selected 1992 Board "NBBInfdletters."
3. List of Recently Issued NRC Information Notices
Attachment 1
-'
IN 92-68 September 10, 1992 .
FAILURE
ANALYSIS
OF A
SLI P-ON
The installation of a 14 "slip-on
flange in a pipeline was recently
witnessed by Al Justin, chief
inspector for the State of Minne- sota. Tieflange originally had a
14-3/4' inside diameter, which
was reduced by welding a 3/4"
ring and machine welding. The
LII#
ring, however, separatedfrom thel
flange, giving the appearance of a
Figure 1 Gasket side of flange.
crack. Theflange is reported to
have been manufactured in the People's Republic of China.
Several such flanges have been reported in thefield. All individuals in the
industry should be on the alertfor theseflanges.
The following is a report by Columbus Metallurgical Services, Inc. on the
failure analysis of a slip-on flange.
A 'cracked" 14" diameter slip-on flange was non-destructively inspected by using
magnetic particle, dye penetrant and ultrasonic test methods. The flange was also
checked for material chemical analysis and macro and microstructure. On the basis of
the results and observations reported, the following conclusion is drawn:
The subject slip-on flange is not an integral forging or a casting. It has been
fabricated by welding and machining a ring insert within a large diameter
flange. The flange "cracked" because the welds between the flange and the
insert were inadequate to withstand the bolting pressures.
- .
w--.e.<t-
^.
A.
.
Figure 2: A close-up of the
gasket side showing the
'crack indication.
BACKGROUND
The "cracked" slip-on flange was received by Columbus Metallurgical
Services, Inc. in one piece. It had two diametrically opposite cracks
located on pipe and gasket sides. It has been reported that se% eral
such flanges are in the field. The subject flange has the following
engraved markings on the outside diameter (OD):
"14 300 SO RF B16.5 A105 848 CHINA 02F"
To identify the cause of the failure it was planned to perform dye
penetrant, dry magnetic particle, ultrasonic and radiographic tests on
the subject flange.
Attachment 1
IN 92-68 September 10, 1992 NON-DEsTRUCTIVE TESTS
First, the flange was UT tested from the
_
_
OD. The indications were rather
puzzling because the reflections were
consistently from a cylindrical surface
about 3.75" from the OD. A dry mag-
-
netic particle examination confirmed
that the cracks extended more or less
continuously in a circular path. The
7 A
-
NDT examination was concluded with
[
'
dye penetrant tests as shown in the
H
i -
-
photographs in Figures 1 through 4. It
Figure 3: Pipe side of flange.
was quite evident that the flange was
not a single piece component. A large inside diameter (ID) flange was reduced to a 14"
ID unit by welding a 0.75" thick ring. The welding faces had been machined.
CHEMICAL ANALYSES AND METALLOGRAPHY
The flange was sectioned into four pieces to obtain specimens for chemistry, as well as
for macro and microscopic examination. The original engraved markings have been
retained on one of the segments. The chemical analyses are as follows:
C
Mn
P
S
Si
Cu
Sn
Ni
Cr
Mo
Al
V
Main Flange Steel
.23
.62
.024
.038
.24
.27
.016
.094
.079
.026
.006
.003
Welded Insert Steel
.26
1.02
.017
.039
.28
.063
.003
.050
.046
.032
.008
.000
ANSI/ASTM A 105
.35
.60-1.05
.040
.050
.35 (listed for reference only)
_7 Figure4: A
5Figure
- A
~~-close-up of
E L
A
,,
,
- _
macro ot
,
-
the pipe
a raial
__
side
section.
W ~
showing
E~e
the
4
5 Hl
'crock-.
1
mi
Eutes.
Attachment I
IN 92-68 September 10, 1992 Figure 5 shows the radial macro section
of the flange. Note the insert ring
welded to the main flange. When
another similar piece was further sec- tioned to retrieve specimens for
mounting and polishing, the insert
separated from the main flange. The
general microstructure (ferritic-pearlitic)
at 25X (Nital etch) is shown in Figure 6.
ROCKWELL HARDNESS TEST
Main Flange:
70 HRB
Insert:
78 HRB
72,69,70 HRB
Ave =
76,78,80 HRB
Ave =
Figure 6: Photo showing general
microstructure in the main flange (lower
half). insert (upper half) and weld metal (left
edge). 25X. Nital etch.
No further work was deemed necessarvO
BULLETIN/WINTER 1992
Attachment 2
IN 92-68 September 10, 1992 VOLUME I
-
NUMBER
16 -
3/27/92
Alert Continues for Flanges from China
The Winter 1992 National Board Bullefin
included an article regarding a serious
problem found to exist on 14" slip-on, raised-face flanges.
Since publication, NBBI has learned the
problem described is only one of many
associated with flanges from the Peoples
Republic of China.
NBBI has been provided with a lab report
for a 4" weld neck flange SA-105N B16-5 with a BHN (Brinell Hardness Number) of
up to 500. Also, normalizing and chemis- try requirements do not meet SA-105 requirements.
These flanges have been reported to have
cracks and other surface discontinuities
that might make them unfit for service. In
addition, there have been reports that
some flanges do not meet thickness
requirements. NBBI also has been advised
through reinspection reports that some
flanges may not bear the markings re- quired by the ANSI B16 specification, although they do bear the B16 mark.
NBBI advises double-checking all flanges
with the marking "China," especially
before these flanges are placed in service.
Certainly, flanges that have visible surface
discontinuities or incomplete markings
may be easy to see. But the machined
surfaces of welded flanges can only be
detected through a volumetric form of
NDE. The failure to meet heat treat, mechanical or chemical requirements of
the specifications can only be verified
through metallurgic examination. .
This update is being distributed in the
interest of public safety. Future updates
will be published as more facts are learned.
Further questions or concerns should be
directed to A.M. 'Doc" Matthews, Jr. or
R.D. Schueler, Jr. at National Board head- quarters.
\\-_a
Attachment 2
-
IN 92-68 September 10, 1992 NBBInfoletr/VOLUME I -
NUMNER 17-
5/1/92
Number of Suspect Flanges Growing at
Alarming Rate
The National Board continues to receive
reports of several different types of
flanges, ranging in sizes from 2 " to 20*
and marked 'China," that do not appear
to be in accordance with ANSI B16 as
markings.
As the number of suspect flanges contin- ues to grow, so does the different types of
problems related to these flanges.
To date, over 7,000 have been removed
from service, including 1,600 recently
discovered in a newly-installed pipeline.
An injunction has been ordered to cease
work on the pipeline until the flange
problem has been resolved. The remain- ing 5,200+ flanges have been found
mostly in refineries.
The president of the China Association of
Boiler and Pressure Vessel Inspection, Center of Boiler & Pressure Vessel Inspec- tion & Research of the Ministry of Labour,
P.R.C., Wang Hannuo, has agreed to meet
with National Board Assistant Director of
Inspections John McLouglin, late in May
in Bejing to discuss the problem.
NBBI continues to advise double-checking
all flanges with the marking China,'
especially before these flanges are placed
in service.
Flanges that have visible surface
discontinuities or incomplete markings
may be easy to see. But the machined
surfaces of welded flanges can only be
detected through a volumetric form of
NDE. The failure to meet heat treat, mechanical or chemical requirements of
the specifications can only be verified
through metallurgic examination.
NBBI will continue to publish updates as
information is learned. This update is
distributed in the interest of public safety.
Further questions or concerns should be
directed to A.M. 'Doc" Matthews, Jr. or
R.D. Schueler, Jr. at National Board
headquartersfl
Attachment 2 ..
IN 92-68 September 10, 1992 VOLUME I -
NUMBER 18 -
JUNE 1992 etter
Flange Update: McLoughlin Meets Chinese
Boiler/Pressure Vessel Officials
John D. McLoughlin, assistant director of
Inspections,metwithseveral agendesof the
Chinese government during his recent visit
to the Peoples Republic of China. The visit
was to discuss problems with flanges mnanu- factured in China (and distributed to the
US.).
Two meetings were held in Beijing.
On May 28, 1992, McLoughlin met with
officials of the Center of Boilerand Pressure
Vessel Inspection and Research, as well as
representatives of Sha5ad Prvince Over- seas Trading Corporation, Tian Gong Com- pany. and Oine Xinang Nan Xi U Flare
Company.
Mr. McLoughlin learned that Ding Xinang
Nan Xi Li has shipped seven to eight con- tainers (each with 17 tons of various types
and sizes of flanges) to the US. thmugb
what is believed to be Tacksonville, Florid&
ShipptngwasreportedlyprovidedbyShanxi
Province, Tlan Gong and Billiongold (a
Hong Kong trader with Beijing offices).
Mr. Yang Li Min of Shanxi Province Over- seas Trading Corporation reported that the
base material for these flanges was 25 MN
and possibly 16 MN (both Chinese forging
specifications) and not the A105 identified
on both the flanges and material test report.
It was stated by Mr. Yang U Min that manu- facturing identification on the flanges was
specified by Billiongold (the Hong Kong
trader) and not the flange manufacturer.
McLoughlin by Mr. Su Rung ji, vice premiie
of China. Mr. McLoughlin met with Mr.
Zheng You Mel, director of the Reception
Bureau, State Council, PRIC, Ms. Fan Jia
Nian, assistant director of the Reception Bu- reau, and several members of the Center of
Boiler and Pressure Vessel Inspection and
Research (representing the Ministry of La- bor). CBPV[R has been assisting the Na- tional Board in its investigation
The director of the Reception Bureau was
givencopiesofinformationaccnunulatedaur- ing the course of Mr. McLoughlin's investi- gation and provided witha briefexplanation
of the documents and the significance of
each.
Mr. Zheng You Mei reported that Mr. Su
Rung ji has a great interest in the flange
situation. He said the government appreci- ated the information provided by the Na- tional Board. Mr. Zheng You Mei also said
that a complete report of the meeting would
be provided to Mr. Su Rung i.
The etng concluded after Mr. McLoughln
provided Mr. Zheng You Mei with recom- mrendations on steps the government could
take to assure that steel mills and forging
makers produce material and flanges that
meet ASTM and ANSI specfications. The
National Board will be advised when or if
these recommnenda tions w-i be implxemnted.
Upon his return to the US., Mr. McLoughlin
received thelaboratoryresults of blind flange
and slip on flange tests that were ordered
prior to his departure. Results of these tests
are as follows:
A scnd meeting was arranged for Mr.
Attachment 2 -P
IN 92-68 September 10, 1992 NBBIfoletterivowUmg 1 -NUMUER is-Jums 1992
Flanges continued
1.Blind flange withanidentific of'PP` and
-ked
A1O is reported to be aplatemate- riaL
2Slip on flange with an identifier of USC or
UlSIO and a heat #1406 contains slugged
weld repairs. The W weld repair indicator
required by AIOS Is not stapTed on the
flange. The chemistry does not eet A105.
The mill report does not indicate any type of
heat treat even though the flange is marked
-
AIO5N and has also been weld repaired. '
Finally, photo micographs indicate plate
\\
\\
materiaL The flange makers name is Shou
'_Roles
Gang Machinery Engineering Company.
According to Mr. McLoughlin:This office
M%* NBIonfdLtt? is pubUahed monthly by
AccordinghecNationalzB
3d
of &oilr and Prewuirt
has probably accomplished all it can at this
V
Inp
, 10 Crue Ave=ue, point, with the resources available. The
Cohlubus, Ohio 4329,(614) 888-2D
National Board will publish a spedil edition
of Xte National Boad Bulletin that will ad-
D.I. MCDonaL
dress this problems Hopefully, we will be
Exsputivr Drcw
able to report steps the Chinese government
A.KM Doe Matthews, Jr.
are taking to insure that their flange prod.
ASS3StWt EpAy= Dirctar
ucs meet spedficadon.e
PD. Bnreut
A,
Diractof
WUMMhotIS
The National Board will be providing vanr- sC Nbcos
ous appropriate agencies of the US. govern- ment with information it has acquired
through the investigation processO
I
I
Attachment 3
September 10, 1992
LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issuance
Issued to
92-67
Deficiency in Design
Modifications to Ad- dress Failures of
Hiller Actuators Upon
A Gradual Loss of
Air Pressure
09/10/92
All holders of OLs or CPs
for nuclear power reactors.
92-66
Access Denied to NRC
Inspectors at Five Star
Products, Inc. and
Construction Products
Research, Fairfield, Connecticut
09/01/92 All holders
for nuclear
and all reci
tractor and
tion Status
Book).
power reactors
pients of
"Licensee, Con- Vendor Inspec- Report" (White
92-65
92-64
92-63
92-62
92-61
92-60
Safety System Problems
Caused by Modifications
That Were Not Adequately
Reviewed and Tested
Nozzl e
on Low
Relief
Ring Settings
Pressure Water- Valves
Cracked Insulators in
ASL Dry Type Transformers
Manufactured by Westing- house Electric Corporation
Emergency Response
Information Require- ments for Radioactive
Material Shipments
Loss of High Head
Safety Injection
Valve Stem Failure
Caused by Embrittlement
09/03/92
08/28/92
08/26/92
08/24/92
08/20/92
08/20/92
All holders of OLs or CPs
for nuclear power reactors.
All holders of OLs or CPs
for nuclear power reactors.
All holders of OLs or CPs
for nuclear power reactors.
All U.S. Nuclear Regulatory
Commission licensees.
All holders of OLs or CPs
for nuclear power reactors.
All holders of OLs or CPs
for pressurized water
reactors (PWRs).
OL = Operating License
CP = Construction Permit