ML20134G809
| ML20134G809 | |
| Person / Time | |
|---|---|
| Issue date: | 11/07/1996 |
| From: | Jennifer Davis NRC (Affiliation Not Assigned) |
| To: | Wichman K NRC (Affiliation Not Assigned) |
| References | |
| NUDOCS 9611130368 | |
| Download: ML20134G809 (5) | |
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NUCLEAR REQULATORY COMMISSION WASHINGTON, D.C. 20665 4001 o
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MEMORANDUM T0:
Keith R. Wichman, Acting Chief Materials and Chemical Engineering Branch Division of Engineeri g THRU:
David Terao, Chief Chemical Engineerin nd Metallurgy Section Materials and Chemical Engineering Branch FROM:
James A. Davis, Materials Engineer l
Chemical Engineering and Metallurgy Section Materials and Chemical Engineering Branch
SUBJECT:
TRIP REPORT ON THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS B1 MAIN COMMITTEE AND SUBCOMMITTEE MEETINGS ON OCTOBER 22-24, 1996 IN CHARLOTTE, NC I attended the American Society of Mechanical Engineers (ASME) B1 Subcommittee Meetings in Charlotte, North Carolina on October 23, 1996. The Subcommittee meetings attended were Subcommittee 10 on Miniature Screw Threads UNM, Subcommittee 15 on Metric J Screw Threads, The B1 Technical Advisory Subcommittee, and 81 Subcommittee 1.
I attended the ASME B1 Main Committee meeting on October 24, 1996. Of primary interest to me was the B1 Technical Advisory Subcommittee meeting where the National Institute of Standards and Technology (NIST) funded study conducted by the ASME Center for Research and l
Technology Development on screw-thread gaging was discussed at some length.
l The B1 Subcommittee 1 meeting included discussions on the revision of ASME Standard Bl.1 on Screw Threads. Additional discussions in all of three areas were repeated at the ASME B1 Main Committee meeting.
Many members of the B1 Technical Advisory Subcommittee voiced concerns about the NIST-ASME report.
One concern was that some of the information supplied I
l to the authors of the report was not put in the report. Another complaint was that some of the history of ASME Standard B1 was provided to the authors but l
was not correctly put in the final document. The members also discussed l
questions that were submitted to the authors that were not raised or addressed l
in the final report. One question was,"If System 21 does not insure dimensional conformance, does System 22 or System 23 insure dimensional conformance?" The final concern was that the report has some weaknesses, but l
it does have some positive conclusions. Committee members felt that another study would be beneficial to resolve some of the issues raised in this report.
An example would be,"What influence do thread dimensions have on the pcfa D4 vn-\\6 k 9611130368 961107 PDR ORG EPSASME PDR
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performance of the fastener?" NIST has stated that they do not intend to fund a follow-on study. The committee members commented that the study conclused that the standards and definitions need clarification, and the resolution of this issue is in the charter of the ASME B1 committees. The current standards and definitions are often presented in such a manner that only experts in the field can understand them.
The committee stated that the standards and definitions would be examined and clarified so that the intent is more understandable.
One of the goals of the ASME B1 Subcommittee is to provide oversight of the ongoing revision of ASME Standard Bl.1 on UNS screw threads. A detailed revision was started two years ago and the first draft is scheduled to be released for ballot by the end of this year.
It is anticipated that the issuance of a revised standard will require several years to complete since the standard will be balloted by the ASME B1 Subcommittee, Main Committee, the Standards Council. The main objectives for the revision are: 1) Eliminate any errors in the standard; 2) Clarify the language in the standard; and 3) i -
Shorten the standard to a reasonable length by eliminating any sections that i
do not contribute to the standard. The most significent error to be corrected
' is related to the tables of dimensions with their tolerances. The tables were first developed over 100 years ago and, when the values were recalculated,
.about 10% were found to be in error although the errors were small. The tables previously listed the pitch diameter and the pitch diameter tolerances for nuts and bolts.
The revision substitutes functional diameter and pitch diameter for the pitch diameter as shown in Attachment 1.
For perfect threads, the functional diameter as measured using System 21 is identical to the pitch diameter as measured using System 22. When the threads are not perfect, the pitch diameter and functional diameter will be different.
The j
ASME B1 Subcommittee will examine the ASME 31 documents in an attempt to clarify any sections that are confusing.
?ney will look closely at ASME Bl.7, the standard containing definitions.
One of the members of the Industrial Fastener Institute gave me a copy of their report, " Influence of Thread Geometry on Fastener Performance,"
published in 1996. This study investigated the effect of nut pitch diameter size on the strength and performance of typical tension-type aerospace joints.
A single lot of aerospace bolts were mated with nuts with varying thread l
dimensions from the standard average size to 0.012 inches oversize.
This oversize value exceeds the maximum deviation that we observed during our inspection at San Onofre and is four times the pitch diameter tolerance band.
The deviations in nut size did not significantly affect the average tensile strength, the fatigue life, or the torque-tension relationship. A second study was conducted to determine the effect of pitch diameter size on the strength and performance of commercial cap screw and nut assemblies.
Five pitch diameter combinations were prepared for the bolts and four pitch diameter combinations were prepared for the nuts. The bolts met minimum tensile,, strength requirements even when out-of-tolerance by 109%. Bolts and nuts of various sizes were tested to determine the torque-tension relationship.
In all cases, the nut-bolt combination exceeded the recommended preload and will provide the necessary clamping force. The final study conducted was to determine'if one gaging system would detect out-of-tolerance fasteners better than another system. System 21 detected out-of-tolerance parts equally as well as System 22.
l i
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The next meeting of the ASME B1 Committee will be April 15-17, 1997 in Orlando, Florida.
Attachment i
Distribution:
PDR EMCB RF Central Files BSheron Glainas JStrosnider GMillmals i
DOCUMENT NAME: G:\\ DAVIS \\ASME.81 To receive a copy of this document, indicate in the box C= Copy w/o attachment /anclosure E= Copy with attachment / enclosure N = No copy DE:Ekh.,
U 0FFICE DE:EMCB DE:EMCB G
NAME JDavis:adNG DTerao N Mb DATE
// / Y /96 11/ 6 /96
// / 'Y/96 0FFICIAL RECORD COPY
/
i J
e Le YABLE 3B UIntiS OF SIZE FOR SELECTO CORROINATIONS OF UNSMNRS SERIE3 THREADS E. 6. ;(1)
Internet (1) stefor Pitch Deemotor UNR RApner j Pitch Demmeter 18elet Diemeter one meiner osometer end Diameter Nominal Size Funcitonal Diamotor Deem.
and Sortee Allow.
Functlenal Otometer Totor-BAmm. (3)
ThreadsI6m Designation Class ance Roma. (2)
Gain.
tamm.(2)
RAnn.
ence (14et.)
Close beln.
Bass.
RAen.
EAsm.
ence RAIN.
Teter.
- 6) 3 10 OR 3 000 - 10 UNS 2A 00020 2 9900 2 9851 2 9330 2 9262 0 0088 2 8789 28 2 892 2 913 2 9350 2 9439 0 0089 3 0000 p) 3 14 OR 3 000 - 14 UNS 2A 00018 2 9982 2 9619 2 9518 2 9459 0 0059 2 9131 28 2 923 2.938 2 9536 2 9813 0 0077 3 0000 Hs 3
18 OR 3 000 - 18 UNS 2A 00016 2 9994 2 9897 2 9623 2 9569 0 0054 2 9322 20 9940 2 953 2 9839 2 9709 0 0070 3 0000 6) 3 1/4 10 OR 3 250 to UNS 2A 00021 3 2479 3 2350 3 1829 3.1760 0 0069 3.1288 2B 3 142 3 163 3.1850 3 1939 0 0009 3 2500 (si 3 is4 14 OR 3 250 14 UNS 2A 00018 3 2482 3 2379 3 2018 3 1958 0 0060 3.1631 2B 3 173 3 188 3 2036 3 2114 0 0078 3 2500 841 3 114 18 OR 3 2So to UNS 2A 00010 3 2e84 3 2397 3 2123 3 2088 0 0055 3 1822 28 3 190 3.203 3 2139 3 2210 0 0071 3 2500 I
t41 3 'ti?
IO OR 3 500 - t0 UNS 2A 00021 3 4979 3 4850 3 4329 3 4260 0 0069 3 3788 2B 3 392 3 413 3 4350 3.4440 0 0000 3 5000 (4) 3 182 - 14 OR 3 500 14 UNS 2A 00018 3 4982 3 4879 3 4518 3 4457 0 0061 3 4131 28 3 423 3 438 3 4536 3 4615 0 0079 3 5000 M) 3 1/2 18 OR 3 500 18 UNS 2A 00017 3 4983 3 4896 3 4622 3 4567 0 0055 3 4321 28 3 440 3 453 3 4639 3 4711 0 0072 3 5000 s46 1 $4 to OR 3 750 10 UNS 2A 00021 3 7479 3 7350 3 6829 3 6759 0 0070 3 6288 28 3 642 3 663 3 6850 3 6941 0 0091 3 7500
- 14) J S4 14 OR 3150 14 UNS 2A 00018 3 7482 3 7379 3 7018 3 6957 0 0061 3 8631 2B 3 673 3 688 3 7036 3 7115 0.0079 3 7500 (4; 3 $4 18 OR 3 750 - 18 UNS 2A 00017 3 7483 3 739C 3 7122 3 7066 0 0056 3 6821 2B 3 690 3 703 3 7139 3 7211 0 0072 3 7500 (4) 4 10 OR 4 000 10 UNS 2A O0021 3 9979 3 9850 3 9329 3 9259 0 0070 3 8788 28 3 892 3 913 3 9350 3 9441 0 0001 4.0000 H) 4 14 OR 4 000 - 14 UNS 2A 00018 3 9982 3 9819 3 9518 3 9456 0 0062 3 9131 28 3 923 3 938 3 9536 3 9616 0 0000 4 0000 (4) 4 1/4 - 10 OR 4 250 - 10 UNS 2A 00021 4 2479 4 2350 4 1829 4 1758 0 0011 4.1288 28 4 142 4.163 4.1850 4 1942 0 0002 4 2500 H) 4 It4 14 OR 4 250 14 UNS
?A 00019 4 2481 4 2378 4 2017 4 1955 0 0062 4.1630 2B 4 173 4 188 4 2036 4.2117 0 0061 4.2500 (4) 4 1/2 10 OR 4 500 - 10 UNS 2A 00021 4 4979 4 4850 4 4329 4 4258 0 0071 4.3788 2B 4 392 4 413 4 4350 4 4443 0 0003 4.5000 top 4 12 - 14 OR 4 500 14 UNS 2A 00019 4 4981 4 4878 4 4517 4 4454 0 0063 4 4130 2B 4423 4 438 4 4536 4 4617 0.0061 4.5000 M) 4 3/4 - 10 OH 4 750 - 10 UNS 2A 00022 4 7478 4 7349 4 6828 4 6756 0 0072 4 6287 28 4 642 4 883 4.6850 4 6943 0.0093 4.7500 p) 4 3/4 - 14 OR 4150 14 UNS 2A 00019 4 7481 4 7378 4 7017 4 6954 0.0063 4 8630 28 4 673 4 688 4.7038 4.7118 0 0082 4 7500 61 5 10 OR 5 000 - 10 UNS 2A 00022 4 9978 4 9849 4 9328 4 9256 0 0072 4 8787 28 4 892 4 913 4 9350 4 9444 0.0004 5 0000 (4) 5 14 OR 5 000 - 14 UNS 2A 00019 4 9981 4 9878 4 9517 4 9453 0 0064 4 9130 28 4 923 4 938 4.9536 40619 0 0083 5 0000 (4) 5 114 - 10 OR 5 250 - 10 UNS 2A 00022 5 2478 5 2349 51823 5 1755 0 0073 5 1287 28 5 142 5 163 5.1850 5 1944 0 0094 5.2500 M) 5 114 14 OR 5 250 - 14 UNS 2A 00019 5 2481 5 2378 5 2017 5.1953 0 0064 5 1630 28 5 173 5 ISS 5.2036 5 2119 0 0063 5 2500 tep 5 1s2 10 OR 5 500 10 UNS 2A 00022 5 4978 54549 5 4328 5 4255 0 0073 53787 2B 5392 5 413 5 4350 5 4445 0 0005 5.5000 14# 5 112 14 OR 5 500 - 14 UNS 2A 00019 5 4981 5 4878 5 4517 5 4453 0 0064 5 4130 2B 5423 5 438 5 4538 5 4620 0 0084 5 5000 p) 5 3/4 - to OR 5 750 - 10 UNS 2A 00022 5 7478 5 7349 5 6828 56755 0 0073 5 6287 28 5 642 5883 5 6850 5 0945 0 0095 5 7500 (4) 5 3/4 84 OR S T50 14 UNS 2A 00019 5 7481 5 7378 5 7017 5 6952 0 0065 5 8630 2B 5673 5 888 5.7036 5 7120 0 0004 5 7500 t4> 6
- to OR 6 000 10 UNS 2A 00022 5 9918 5 9849 5 9328 59254 0 0074 5 8787 28 5892 5 913 5 9350 5 9446 0 0096 6 0000 (4) 6 14 OR 6 000 14 UNS 2A 00020 5 9900 5 9877 5 9516 5 9451 0 0065 59129 2B 5923 5 938 5 9536 5 9621 0 0085 60000 i
tal sevies des gnation shown w dicates the UN ttwead form, however, the UNR thread form may be specaed by sut>st4uting UNR en place of UN et as Gesagnetsons for e te r
a use only.
Notes y
-1 (1) Thread classes may toe combined See para 4 2.
- 12) F or Class 2A ttweads hawmg an addeteve finish. the marynum mator and petdt diameters, aftes coateg, may equal the bassc stres. whose values are Q
shown los Class 3A m these columns See paras 41 1 and 41.3 ues g
(3) UN screes enterstal thread massmum mmor dsameter es bassC (Of an section 11 for Class 3A and basic meus allowance for Classes 1 A 3
z MI One or more et the numt>ess listed m this row have been changed to correct for calculahon and rounding errors The ongmal numbers Ikom past issues of 81 1H are bsted n appenden - - and are for reference only
l The n gt meeting of the ASME B1 Committee will be April 15-17, 1997 in Orlando, Florida.
Attachment i
Distribution:
PDR i
EMCB RF i
l Central Files j
BSheron Glainas JStrosnider GMillman l
DOCUMENT NAME: G:\\ DAVIS \\ASME.81 To receive a copy of this document, indicate in the box C= Copy w/o attachment / enclosure E= Copy with attachment / enc 1osure N = No copy DE:Ekh,lU 0FFICE DE:EMCB DE:EMCB C-JDavis:ahh DTerao M Mb NAME DATE
// / Y /96 ft/ 6 /96
// / Y/96 0FFLCIAL RECORD COPY
/