High cycle fatigue of austenitic stainless steels

European Commission Directorate-General For The Information Society And Media Directorate-General For Research And Innovation

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Nuclear energy and safety

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• Publié par: EUROPEAN-COMMISSION-DIRECTORATE-GENERAL-FOR-THE-INFORMATION-SOCIETY-AND-MEDIA-DI
• Nombre de lectures: 13
• Langue: English
• Poids de l'ouvrage: 3 Mo

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Commission of the European Communities
nuclear science
and technology
High cycle fatigue
of
austenitic stainless steels
Report
EUR 13084 EN Commission of the European Communities
nuclear science
and technology
High cycle fatigue
of
austenitic stainless steels
J.P. Gauthier, D. Lehmann
Commissariat à l'énergie atomique
Centre d'études nucléaires de Saclay
F-91191 Gif-sur-Yvette
In cooperation with
Dr Picker
AEA — Technology
Risley
Dr Meurer
Interatom
Bergisch Gladbach
CONTRACT No RA 1 -0091 -F
Final report
This work was performed under the
Commission of the European Communities
for the: working group 'Codes and standards'
activityp 3: 'Materials'
within the Fast Reactor Coordinating Committee
Directorate-General
Science, Research and Development
1990 EUR 13084 EN Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Telecommunications, Information Industries and Innovation
L-2920 Luxembourg
LEGAL NOTICE
Neither the Commission of the European Communities nor any person acting on
behalf of then is responsible for the use which might be made of the
following information
Cataloguing data can be found at the end of this publication
Luxembourg: Office for Official Publications of the European Communities, 1990
ISBN 92-826-1904-4 Catalogue number: CD-NA-13084-EN-C
© ECSC-EEC-EAEC, Brussels · Luxembourg, 1990
Printed in Belgium FOREWORD AND EXECUTIVE SUMMARY
The Commission of the European Communities is assisted in its actions
regarding fast breeder reactors by the Fast Reactor Coordinating
Committee which has set up the Safety Working Group and the Working
Group Codes and Standards (WGCS). The letter's mandate is to harmonize
the codes, standards and regulations used in the EC member countries for
the design, material selection, construction and inspection of LMFBR
components.
The present report is the revised final report of CEC Study Contract
N° RA1-0091-F performed under WGCS/Activity Group 3 : Materials. As most
AG3 work, this study concerned the evaluation of material data to be
used in LMFBR design codes. The main contractor was CEA (France) with
UKAEA (UK) and INTERATOM (FRG) as participants.
The report concerns the evaluation of high cycle fatigue properties of
three austenitic stainless steels : type AISI 316 (UKAEA tests), type
AISI 316L (CEA tests) and type AISI 304 (INTERATOM tests). The data on
these steels comprised some 550 data points from 14 casts. This data set
covered a wide range of testing parameters : temperature from 20 to
625°C, frequency from 1 to 20,000 Hz, constant amplitude and random
fatigue loading, with and without mean stress etc. However, the testing
conditions chosen by the three partners differed considerably because
they had been fixed independently and not harmonised prior to the tests.
This created considerable difficulties when the results were pooled for
the evaluations to be performed in the present study.
Experimental procedures and statistical treatments used for the three
sub-sets of data are first described and discussed. Results are
presented in tables and graphs. Although it is often difficult to single
out the influence of each parameter due to the different testing
conditions, several interesting conclusions can be drawn :
- The HCF properties of the three steels are consistent with the 0.2 %
proof stress, the fatigue limit being larger than, the latter at
temperatures above 550°C. The type 304 steel has lower tensile
properties than, the two other steels and hence also lower HCF
properties.
- Parameters which clearly have a significant effect on HCF behaviour
are mean stress or R-ratio (less in the non endurance region than in
the endurance region), temperature, cast or product.
- Other parameters have probably a weak or no effect but it is difficult
to conclude due to insufficient data : environment, specimen
orientation, frequency, specimen geometry.
Recommendations for future work conclude the report. One of these is
that partners of collaborative actions should agree on a common test
matrix and experimental procedures prior to any testing.
L.H. Larsson
III CONTENTS
Page
1 - INTRODUCTION 1
2 - SUPPLY OF AVAILABLE DATA and EXPERIMENTAL METHODS 2
2.1 - Supply of available data 2
2.2 - High cycle fatigue experimental methods 4
3 - PRESENTATION OF THE DATA COLLECTION 6
3.1 - Establishment of the data bank
3.2 - Presentation of the data 7
3.3 - Use of the data bank 8
4 - EVALUATION OF THE HIGH CYCLE BEHAVIOUR OF THE 304-316-316L
AUSTENITIC STAINLESS STEELS
4.1 - Methodology
4.2 - Comparison of the behaviour of the different types
of materials 9
4.2.1 - Type 304 and 316 steels
4.2.2 - Type 304 and 316Ls 10
4.2.3 - Type 316 and 316L steels
4.2.4- Conclusion 11
4.3 - Effect of other experimental parameters
4.3.1 - Effect of a mean stress
4.3.2 -t of R ratio2
4.3.3 - Effect of temperature
4.3.3.1 - Type 316 steel
4.3.3.2 - Type 304 stell3 - Type 316L steel 1
4.3.4 - Effect of environment3 5 -t of the orientation of the specimens 1
4.3.6 - Effect of cast to cast (or product to product)
variability 1
4.3.6.1 - Type 304 steel
4.3.6.2 - Type 316L steel4
4.3.7 - Effect of the frequency5
4.3.8 -t of the specimen geometry 1
5 - GENERAL DISCUSSION6
5.1 - Data base 1
5.2 - Experimental methods
5.3 - General data8
5.4 - Comparison between materials
5.5 - Effect of different parameters9 5.5.1 - Parameters having a significant and
sometimes strong effect 19
5.5.1.1 - Material2 - Mean stress-and R ratio 20
5.5.1.3 - Test temperature4 - Cast or product
5.5.2 - Parameters having probably a weak effect or no
effect but for which it is difficult to conclude
due to lack of data 21
5.5.2.1 - Environment2 - Specimen orientation
5.5.2.3 - Frequency
5.5.2.4 - Specimen geometry
6 - RECOMMENDATIONS AND PERSPECTIVES2
7 - CONCLUSIONS 23
REFERENCES6
APPENDICES9
Appendix 1 Data to be provided 31
Appendix 2 UKAEA datax 3 INTERATOM data4
Appendix 4 (4-1, 4-2, 4-3) : CEA data5 x 5 Truncation of peaks in narrow band random
amplitude high cycle fatigue testing using
a resonant machine8
TABLES 41
FIGURES 73
VI — 1 - INTRODUCTION
For major LMFBR components high cycle fatigue (HCF) has not yet
been considered as an essential cause of damage. However, it appears that
in some situations this factor has to be considered. These situations are
essentially related to thermal oscillations (thermal striping) or vibra­
tions.
Up to now, essentially data on low cycle fatigue (LCF) are avail­
able and very often, for high cycle fatigue evaluation, these low cycle
fatigue data are extrapolated for higher cycles to rupture. Some results
and the collection of low cycle fatigue data made in a previous study
contract (RAP-027-F) indicate that these extrapolations are generally over-
conservative.
As the available data, in terms of endurance limit, are relatively
scarce in each country, it appeared to be very profitable to put all the
data together and to derive some recommendations for high cycle fatigue
evaluation. The purpose of this study is:
1. to collect information on methods for HCF evaluation in different
countries
2. to collect the available data in terms of :
. individual results
. determination of the endurance limit using statistical methods (stair­
case)
This data collection would be restricted to load controlled tests
but would include push pull tests, rotating bending tests etc...
3. To analyse the data examining the connection between LCF tests (strain
controlled) and HCF tests (load controlled) as well as the influence of
specimen geometry and surface roughness.
The contract was placed with CEA, who has subcontracted with UKAEA
(Risley) and Interatom (Bensberg).
1 -This report details HCF data supplied by CEA (France), UKAEA (Great
Britain) and INTERATOM (Germany), and derived from a data bank especially
built by CEA in the frame of this CEC contract.
These data are discussed and analysed. The main work concerns the
effect of different experimental parameters on the S-N curves, which are
derived from the tables 10 to 58 of the data bank. A particular emphasis is
made on the relative behaviour of the different types of stainless steels:
304, 316 and 316 L.
2 - SUPPLY OF THE AVAILABLE DATA and EXPERIMENTAL METHODS
2.1- Supply of available data
Appendices2, 3 and 4 give respectively the UKAEA, INTERATOM and CEA da­
ta according to a format previously agreed by the participants (Appendix 1).
The stainless steels tested are :
- type AISI 316 for UKAEA
- type AISI 304 for INTERATOM (DIN 1.4948/X6CrNil8-ll)
- type AISI 316L for CEA (AFNOR Z2CND17-12)
UKAEA data include the effects of :
- cast to cast variation
- form of product
- type of cycling (sine or NBR : narrow band random, corresponding to an
irregularity factor of I =99 %)
For the NBR loading, the effe