small punch creep tests for grade 92 forgings · 2018. 10. 6. · seven specimens rwere extracted...
TRANSCRIPT
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Small Punch Creep Tests for Grade 92 Forgings
ECCC WG 3A report
Kappou, E
Holmström, S
2018
EUR 29360 EN
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This publication is a Technical report by the Joint Research Centre (JRC), the European Commission’s science
and knowledge service. It aims to provide evidence-based scientific support to the European policymaking
process. The scientific output expressed does not imply a policy position of the European Commission. Neither
the European Commission nor any person acting on behalf of the Commission is responsible for the use that
might be made of this publication.
JRC Science Hub
https://ec.europa.eu/jrc
JRC113068
EUR 29360 EN
PDF ISBN 978-92-79-93959-4 ISSN 1831-9424 doi:10.2760/12580
Luxembourg: Publications Office of the European Union, 2018
© European Atomic Energy Community, 2018
Reuse is authorised provided the source is acknowledged. The reuse policy of European Commission documents is regulated by Decision 2011/833/EU (OJ L 330, 14.12.2011, p. 39).
For any use or reproduction of photos or other material that is not under the EU copyright, permission must be
sought directly from the copyright holders.
How to cite this report: Kappou, E. and Holmstrom, S., Small Punch Creep Tests for Grade 92 Forgings, EUR 29360 EN, Publications Office of the European Union, Luxembourg, 2018, ISBN 978-92-79-93959-4, doi:10.2760/12580, JRC113068.
All images © European Atomic Energy Community, 2018 unless otherwise specified
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Contents
Acknowledgements ................................................................................................ 1
Abstract ............................................................................................................... 2
1 Introduction ...................................................................................................... 3
2 Materials and methods ........................................................................................ 4
2.1 Material and specimens ................................................................................. 4
2.2 Test rig and experimental procedure .............................................................. 5
3 Experimental ...................................................................................................... 7
3.1 Description of testing procedure and methods ................................................. 7
3.2 Results and discussion .................................................................................. 9
2 Conclusions .................................................................................................... 12
References ......................................................................................................... 13
List of figures ...................................................................................................... 14
List of tables ....................................................................................................... 15
Annexes ............................................................................................................. 16
Annex 1. Test curves and top views of tested samples, Q/T F92 ............................ 16
Annex 2. Test curves and top views of tested samples, N/T F92 ............................ 23
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1
Acknowledgements
Special thanks to my supervisor Stefan Holmström for his precious help and guidance. I
would also like to thank Matthias Bruchhausen and Stefan Ripplinger for the knowledge
they transmitted to me. Special thanks to Franchini Acciai SpA for the test materials and
material expertise. Support from the ECCC WG1 and WG3A are gratefully acknowledged.
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Abstract
This report has been prepared for the ECCC WG 3A as an in kind contribution of JRC. The
report compares the creep strengths of two F92 forgings (Grade 92 steel) with differing
heat treatments. The two heat treatments are normalizing and tempering and quenching
and tempering. The comparison is entirely based on small punch creep (SPC) data
analysis. The SPC test samples were extracted from different orientations of the bulk
materials. The calculated equivalent stresses of the tests are converted using the
equations recommended in the soon to be published small punch standard. Also, a new
simplified method of determining the minimum deflection rate and deflection at minimum
deflection rate is described and result in equal creep strength estimates. It is shown that
the quenched and tempered steel is about 30% stronger than the normalized and
tempered forging in short duration creep.
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1 Introduction
Miniature testing techniques have many uses and are excellent for testing in service
materials, such as nuclear power plants, to support life extension investigations and/or
determining the current material state. The small punch test (SP for "tensile" properties
and SPC for creep properties) is a method for evaluating the mechanical properties of a
material with minimal amount of material causing negligible destructive intrusion on the
components under investigation [1-5]. In the SP tests a thin disc shaped specimen is
manufactured from the bulk material in a specified direction. The SP tests do not only
allow for the evaluation of real components by using materials with limited size, but can
also pin-point critical locations impossible to be targeted by the conventional methods
[5][6]. As for creep, the SPC test is a simple and economical method that has the
potential to for some extent replace the shorter duration conventional uniaxial creep test
[7][8].
The work presented in this report has been performed for the European Creep
Collaborative Committee (ECCC). ECCC has been active as leading European network in
the assessment of high temperature materials for standardisation, pressure equipment
design, and component integrity since 1992. The ECCC was founded as an EU project,
but is now independently governed by European industry as a series of Joint Industrial
Projects (JIP). JRC is a member of the ECCC JIP2 and 3 (2015-2020). JRC is actively
contributing in kind to the network for the Work Groups 1 (general modelling), 3a
(Ferritic steels) and 3b (Austenitic steels). Miniature testing techniques is a sub-work
group under WG1 with a special interest in small punch creep testing (SPC) and the test
results conducted on the ECCC F92 materials is JRC contribution to WG3a. This report is
linked to the two first mentioned WGs.
The main outcome of this report is supporting the validation of the SPC tests for
determining the short term creep properties of steels. Here fourteen SPC tests conducted
on two heavy wall tubular forgings of grade 92 are assessed. The two forgings were
subjected to different heat treatments, namely normalizing & tempering (N/T) and
quenching and tempering (Q/T), respectively (designated as F92).1 The test results are
mainly compared with regard to their equivalent stresses and rupture times.
1 The details of the heat treatments are confidential.
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2 Materials and methods
2.1 Material and specimens
The small punch ECCC test programme in Work Group 3a (Ferritic steels) was adapted to
support the ongoing standardization work of ECISS / TC101 / WG1 and was extended to
evaluate the differences in creep resistance induced by two heat treatments performed
on forged grade 92 materials. The test programme includes room temperature and high
temperature SP tests for estimating the proof strength (Rp02) and the ultimate tensile
strength (Rm) as well as determining the differences in creep strength. In this report the
emphasis is laid on the creep strength evaluation. In
Table 1, the specimens coming from the two materials under investigation, i.e. F92
forgings produced by FRANCHINI ACCIAI SpA (Mairano, Italy), are presented.
Table 1. The ECCC F92 forgings and their tensile (uniaxial) properties at room temperature.
Test
groups
Heat
treatment
Rp02
(RT)
MPa
Rm
(RT)
MPa
El
(%)
RA
(%) Rp02/Rm
Uniaxial
creep data
CT &
CD
Normalized
and
tempered
(N/T)
470 645 25.4 58 0.73 Assessor only
1)
DA
Quenched
and
tempered
(Q/T)
648 775 21.5 61 0.84
Not
disseminated 2)
1) The uniaxial time to rupture data for the F92 steel is confidential within ECCC 2) Might become available within ECCC
The difference in proof strengths between the two materials shows that the Q/T is
stronger and has higher yield strength. This explains the larger deflections found in the
N/T specimens (for the same force) at loading and during the SPC tests.
The extraction orientation of the small punch test specimens could also have had a small
effect on the properties of the material. The specimens can be extracted from the target
component in different directions as shown in Figure 1. For a pipe type of component L is
the longitudinal direction, R the radial direction and C the circumferential (hoop)
direction. The specimen extraction directions in the test reported here, are given in Table
2 as indicated by the letter R or L appended to the material name. For the assessment
presented here the orientation of the specimen was not taken into account.
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5
Figure 1. Orientation of SPT specimens [9].
2.2 Test rig and experimental procedure
In small punch creep (SPC) tests, a cylindrical rod or puncher with a hemispherical tip or
a flat punch combined with a ball is forced through the metal disc shaped specimen. In
the case of SPC the force is constant and the specimen is deformed as a function of time
by creep. The temperature is held constant in the test and the test is continued until the
specimen ruptures. The main test result is the time deflection curve.
The specimen holder consists of two dies that clamps the specimen so that the specimen
cannot bend upwards. At JRC a flat puncher is combined with a 2.5 mm ball. The
receiving hole in the lower die has a diameter of 4 mm with 0.2 mm deep 45 chamfer.
The deflection u is measured from below, via a ceramic rod transferring the movement to
an LVDT. The temperature T is controlled and measured by a calibrated N thermocouple
(TC) integrated in the sample holder touching the inner die. A furnace is heating the test
assembly. During the test argon gas is flowing into the specimen holder to avoid
oxidation. A simplified SPC set-up is shown in Figure 2.
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Figure 2. Simplified presentation of a small punch test device [2].
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7
3 Experimental
3.1 Description of testing procedure and methods
Seven specimens were extracted in the L and R directions for the N/T F92 steel. These
were compared to seven Q/T specimens extracted in the L direction. The specimens were
tested at different forces and temperatures with the aim of estimating the uniaxial creep
strengths of the respective materials. Other mechanical properties such as fracture strain
and reduction of area were also targeted. The assessment on equivalent stress as a
function of time to rupture and creep rate is based on the time-deflection-time curves.
The equivalent stress is calculated from a "force to stress conversion" equation =F/, as
it is described below in Equations 2-3.
A comparison was also conducted between the standard way of calculating the minimum
deflection rate [9] and a new simplified methodology to extract a representative
deflection for equivalent stress calculation. Since there is a strong dependence between
the estimated equivalent stress and the measured deflection at the minimum deflection
rate a robust methodology for extracting it is very important [7].
The calculation of minimum deflection rate (du/dt) from the time-deflection rate curve is
not always an easy issue. The minimum deflection rate is defined as the minimum slope
in the time-deflection curve and traditionally its value can be extracted from the
minimum point in the time-deflection rate curve. The differentiation of "noisy" data can
lead to scatter if sub optimal amount of data points are used for calculating the deflection
rate. The deflection rate versus time curve can cause significant differences in the
location when finding the "minimum" location. Especially for less ductile materials than
for brittle, more scatter has been observed. As a result, it is difficult to determine the
position of the minimum. A not very smooth curve could create problems in the
determination of the deflection. The new method based on the time to rupture could
simplify the conversion of SPC equivalent stress and reduce the scatter for the creep
strength estimation.
According to the new method, instead of finding the minimum deflection rate and the
deflection at minimum deflection rate the alternative deflection and rate are calculated
directly from the time-deflection curve without differentiating. The deflection umin is
replaced by the deflection at ½ life (u1/2) and the minimum deflection rate is the slope
between the deflections at 1/3 and 2/3 of life as given in Equation 1. The simplified
method is shown in Figure 3.
�̇�1/2 = (𝑢2
3−
𝑢1
3 ) (
2𝑡r
3−
1𝑡r
3⁄ ) (1)
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Figure 3. Prediction of u1/2 and u1/2-rate by using the new method.
After using both methods to determine the deflection at minimum deflection rate values,
the corresponding equivalent stresses are calculated. As incorporated in the new small
punch pre-standard, the most difficult part of using SPC tests for predicting the uniaxial
creep properties is the conversion between the applied force F in a SPC test to the
equivalent uniaxial stress at equal rupture times.
The empirical force to stress (EFS) ratio =F/ that is a fully empirical model based on a
large number of test for multiple materials that have both uniaxial and SPC data
[7][9][10].
The equivalent stresses according to the EFS using the deflection at minimum deflection rate (Ϭumin) and by using the deflection at ½ life (Ϭu1/2), were calculated by Equation 2
and Equation 3 respectively.
1 =𝐹
Ϭumin= 1,920 ∗ 𝑢min
0,6530 (2)
2 =𝐹
Ϭu1/2= 1,920 ∗ 𝑢1/2
0,6530 (3)
For calculating an estimate of the strength factor between the two heat treatments the
Larson-Miller (LM) model was used to include the tests performed at different
temperatures. The Larson-Miller Parameters method (PLM) is based on the Arrhenius
equation and gives the relation between stress, temperature and rupture time [2]. It has
been widely used in life prediction and it is the simplest time-temperature parameter
approach. It has been found that this model works rather well in interpolation and in a
limited range for extrapolations towards shorter test durations [2][7]. The PLM is defined
in Equation 4, where T is temperature given in Celsius (C) and tr the time to rupture in
hours (h). The constant C of the PLM has been optimized earlier for P92 steel [7]. For the
F92 materials the parameter C=32 was used.
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𝑃𝐿𝑀 =(log(𝑡r)+𝐶)∙(𝑇+273)
1000 (4)
3.2 Results and discussion
In Table 2 the results are given for each SPC test. For each test temperature, force, time
to rupture (tr), minimum deflection rate (min-rate) and deflection at minimum deflection
rate (umin) are given together with the calculated equivalent stress. The values of u1/2-
rate and u1/2 were also calculated, by using the simplified methodology. All test curves
with their extracted values are given as Annexes 1-2. The equivalent stresses were
predicted by using the EFS equations and the PLM calculated for comparing the creep
strengths.
Table 2. SPC test results.
Specimen Material Force (N)
Temperature (
0C)
tr (h) min-rate u1/2-rate umin (mm) u1/2 (mm) Ϭumin (N) Ϭu1/2 (N) PLM (C=32)
CD-050 N/T-L 500 600 26.75 0.016514 0.017068 1.472393 1.467646 202.3 202.7 29.18205
CD-046 N/T-L 550 600 14.78 0.030319 0.031849 1.607512 1.613841 210.1 209.6 28.95713
CD-051 N/T-L 550 600 12.35 0.031517 0.034893 1.509416 1.515745 219 218.3 28.88903
CD-048 N/T-L 600 600 3.61 0.129885 0.135455 1.484101 1.484417 241.5 241.4 28.42270
CT-010 N/T-R 300 650 147.14 0.002424 0.002819 1.351196 1.384739 128.4 126.3 31.53682
CT-006 N/T-R 350 650 56.11 0.006573 0.007687 1.486945 1.478375 140.7 141.2 31.15036
CT-009 N/T-R 500 600 38.27 0.010446 0.011010 1.489164 1.516061 200.8 198.5 29.31784
DA-003 Q/T-L 500 600 96.11 0.002361 0.002598 1.551186 1.575552 195.5 193.5 29.66696
DA-004 Q/T-L 550 600 52.13 0.004561 0.004844 1.198989 1.228102 254.4 250.5 29.43502
DA-008 Q/T-L 600 600 34.09 0.007325 0.008299 1.098994 1.127474 293.8 289.0 29.27398
DA-007 Q/T-L 450 650 12.12 0.037315 0.040968 1.637258 1.656561 169.9 168.6 30.53607
DA-001 Q/T-L 550 650 4.28 0.106064 0.112141 1.431572 1.478722 226.6 221.9 30.11882
DA-002 Q/T-L 350 650 66.62 0.007057 0.007723 1.104370 1.078110 170.8 173.5 31.21921
DA-009 Q/T-L 300 650 197.68 0.001919 0.002123 0.924953 0.947736 164.4 161.8 31.65516
As shown in Annex 2, the test specimen CD-046 was tilted during the tests since the
specimen was not properly centred in the lower die. As a result, the puncher did not
punch the specimen in the centre. Thus, a re-test was conducted at the same
temperature-load conditions (CD-051). The comparison of the results of these two
specimens showed umin and tr values very close to each other. The tilted specimen did not
affect the calculated equivalent stress very much.
The calculated equivalent stresses (Ϭumin) of specimens made from N/T-L and Q/T-L
materials tested in 600OC, are plotted against tr in Figure 4. The equivalent SPC stresses
depend on the SPC test curve. Thus, N/T specimens with higher umin give lower
equivalent stresses at equal applied force. In contrast, the stronger Q/T specimens with
lower umin have higher equivalent stresses compared to the N/T at the same applied
force. The linear fits of Q/T and N/T specimens, respectively, indicate small deviations
from linear behaviour at 600°C.
The Ϭumin of both materials tested at 650OC are also plotted versus tr in Figure 4, though
it is apparent that some of the Q/T don’t fit as well on a linear fit.
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10
a) b)
Figure 4. N/T-L and Q/T-L specimens plotted in a tr- Ϭumin plot at a) 600OC, b) 650OC.
The equivalent stresses (Ϭumin) of both N/T and Q/T specimens, for all temperatures, are
plotted against the PLM in Figure 5. The lower equivalent stresses of N/T specimens in
comparison to Q/T can clearly be seen. The Q/T strength is approximately 1.3 times the
N/T strength.
Unexpectedly, two of the Q/T specimens showed similar behaviour as the N/T material.
The specimen DA-007 and DA-003 showed lower equivalent stresses, similar to N/T
specimens. The discrepancy may be due to the large umin measured in these tests. A
possible source of error is the offset of the LVDT at loading.
In order to check this, the deflection at the beginning of the test, u0 (see Figure 3), i.e.
deflection after loading was extracted. The u0, was also extracted for the test at the same
temperature and a higher load. Thus, the u0 of DA-003 has been compared with the u0 of
"normally" behaving DA-004 as given in Table 3. Despite the 50 N higher force for DA-
004 than DA-003 it had a higher u0 value. This finding can indicate inaccuracy of LVDT
signal at loading for the outlier DA-003. Similarly, the u0 of DA-007 was compared with
the u0 of DA-001 with similar outcome.
Figure 5. The Larson-Miller fitting results of both N/T and Q/T specimens. The blue arrows indicate the specimens that showed large u0 values.
y = -1.5393x + 341.48R² = 0.9851
y = -1.0755x + 235.31R² = 0.7649
0
50
100
150
200
250
300
350
0 20 40 60 80 100 120
Ϭumin
tr
Q/T-L
N/T-L
600
y = -0.1851x + 195.93R² = 0.3197
y = -0.1353x + 148.28R² = 1
0
50
100
150
200
250
0 50 100 150 200 250
Ϭumin
tr
Q/T-L
N/T-L
650
y = -45.38x + 1584.5R² = 0.6955
y = -34.784x + 1223.6R² = 0.9905
0
50
100
150
200
250
300
350
28 28.5 29 29.5 30 30.5 31 31.5 32
Equ
ival
en
t st
ress
Larson-Miller/1000, C=32
Q/T
N/T
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Table 3. u0 of Q/T specimens that showed unexpected deflections (marked with *) and the tests
that were compared for deflection at loading.
Specimen Force (N) Temperature (0C) U0 (mm)
DA-003* 500 600 0.87
DA-004 550 600 0.57
DA-007* 450 650 0.77
DA-001 550 650 0.78
The higher tensile strength and higher yield of the Q/T material can also explain their
lower values of minimum deflection rate for the rather short tests.
With the aim of comparing the standard and the new simplified assessment method the
equivalent stresses of all tests were plotted against each other. The same was done for
the minimum deflection rate. Figure 6 shows the correlations between the determined
test results. The two calculated slopes and the R-squared values are very close to unity,
indicating that both methods give the same predictions.
a) b)
Figure 6. N/T and Q/T specimens plotted together in a a) Ϭu1/2 versus Ϭumin chart, b)
u1/2-rate versus umin-rate.
y = 0.9917xR² = 0.9979
0
50
100
150
200
250
300
350
0 50 100 150 200 250 300 350
Ϭumin
Ϭu1/2
y = 0.9808xR² = 0.9994
-3
-2.5
-2
-1.5
-1
-0.5
0
-3 -2.5 -2 -1.5 -1 -0.5 0
log
(min
-rat
e)
log (u1/2-rate)
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2 Conclusions
In this report the two heat treatments of F92 forgings have been compared for their
creep strengths and deflection rates. The main conclusions are;
The Q/T material is about 30% stronger than the N/T in short term creep.
The softer N/T material has higher deflections at minimum deflection rate causing
lower equivalent stresses at equal force than the Q/T material.
The new simplified method of predicting the minimum deflection rate and the
deflection at minimum deflection rate give the same results as the more scatter
prone standard methodology.
A tilted specimen did not affect the calculated equivalent stress and not the time
to rupture.
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References
[1] M. Bruchhausen, S. Holmström, I. Simonovski, T. Austin, J.-M.
LapetiteS.Ripplinger, F. de Haan, “Recent developments in small punch testing:
Tensile properties and DBTT”, Theoretical and Applied Fracture Mechanics, vol.
86, pp. 2-10, 2016.
[2] M. Bruchhausen, S. Holmström, J.-M. Lapetite, S. Ripplinger, “On the
determination of the ductile to brittle transition temperature from small punch
tests on Grade 91 ferritic-martensitic steel”, International Journal of Pressure
Vessels and Piping, 2017.
[3] C. Wen, T. Xu, K. Guan, “Correlation Factor Study of Small Punch Creep Test
and Its Life Prediction”, Materials, vol. 9, Issue 10, 2016.
[4] Y. Zheng, S. Yang, X. Ling, “Creep life prediction of small punch creep testing
specimens for service-exposed Cr5Mo using the theta-projection method”,
Engineering Failure Analysis, 2016.
[5] P. Dymáček, “Recent developments in small punch testing: Applications at
elevated temperatures”, Theoretical and Applied Fracture Mechanics, 2016.
[6] D. Andrés, R. Lacalle, and J. A. Álvarez, “Creep property evaluation of light
alloys by means of the Small Punch test: Creep master curves,” Materials &
Design, vol. 96, pp. 122–130, 2016.
[7] S. P. Jeffs, R. J. Lancaster, and T. E. Garcia, “Creep lifing methodologies applied
to a single crystal superalloy by use of small scale test techniques,” Materials
Science and Engineering: A, vol. 636, pp. 529–535, 2015.
[8] S. Holmström, Y. Li P. Dymacek, E. Vacchieri, S.P. Jeffs, R.J. Lancaster, D.
Omacht, Z. Kubon, E. Anelli, J. Rantala, A. Tonti, S. Komazaki, Naveena, M.
Bruchhausen, R.C. Hurst, P. Hähner, M. Richardson, D. Andres, “Creep strength
and minimum strain rate estimation from Small Punch Creep tests”, Mater. Sci.
Eng. A, vol. 731, pp. 161–172, 2018.
[9] S. Yang, X. Ling, Y. Zheng, “Creep behaviors evaluation of Incoloy 800H by
small punch creep test”, Mater. Sci. Eng. A, vol. 685, pp. 1-6, 2017.
[10] ECISS/TC 101-prestandard, “Metallic materials - Small punch test
method”, 2017.
[11] F. Dobeš, P. Dymáček, “Fracture-based correlation of uniaxial and small
punch creep data”, Theor. App. Fra. Mec., 2016.
https://www.sciencedirect.com/science/article/pii/S0167844216301677?via%3Dihub#!https://www.sciencedirect.com/science/article/pii/S0167844216301677?via%3Dihub#!https://www.sciencedirect.com/science/article/pii/S0167844216301677?via%3Dihub#!https://www.sciencedirect.com/science/article/pii/S0167844216301677?via%3Dihub#!https://www.sciencedirect.com/science/article/pii/S0167844216301677?via%3Dihub#!https://www.sciencedirect.com/science/article/pii/S0167844216301677?via%3Dihub#!https://www.sciencedirect.com/science/article/pii/S0167844216301677?via%3Dihub#!https://www.sciencedirect.com/science/article/pii/S0167844216301677?via%3Dihub#!
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List of figures
Figure 1. Orientation of SPT specimens [9]. .............................................................. 5
Figure 2. Simplified presentation of a small punch test device [2]. ............................... 6
Figure 3. Prediction of u1/2 and u1/2-rate by using the new method. .............................. 8
Figure 4. N/T-L and Q/T-L specimens plotted in a tr- Ϭumin plot at a) 600OC, b) 650OC. .10
Figure 5. The Larson-Miller fitting results of both N/T and Q/T specimens. The blue
arrows indicate the specimens that showed large u0 values. .......................................10
Figure 6. N/T and Q/T specimens plotted together in a a) Ϭu1/2 versus Ϭumin chart, b) u1/2-
rate versus umin-rate. ............................................................................................11
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15
List of tables
Table 1. The ECCC F92 forgings and their tensile (uniaxial) properties at room
temperature. ........................................................................................................ 4
Table 2. Results of tested specimens. ....................................................................... 9
Table 3. u0 of Q/T specimens that showed unexpected deflections (marked with *) and
the tests that were compared for deflection at loading. .............................................11
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16
Annexes
Annex 1. Test curves and top views of tested samples, Q/T F92
Sample: F92 DA-001 (650OC, 550N)
F92 DA-001 (650
OC, 550N)
T=650OC
F=550N
DA-001
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
4.28h 0.106mm/h 1.695h 1.431mm
Time-deflection curve & Time-deflection rate curve (T=650OC F=550N)
0.1
1
10
100
1000
10000
0
0.5
1
1.5
2
2.5
0 1 2 3 4 5
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
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17
Sample: F92 DA-002 (650OC, 350N)
F92 DA-002 (650OC, 350N)
T=650OC
F=350N
DA-002
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
66.62h 0.007mm/h 36.43h 1.104mm
Time-deflection curve & Time-deflection rate curve (T=650OC F=350N)
0.001
0.01
0.1
1
10
100
1000
10000
100000
0
0.5
1
1.5
2
2.5
0 10 20 30 40 50 60 70
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
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18
Sample: F92 DA-003 (600OC, 500N)
F92 DA-003 (600OC, 500N)
T=600OC
F=500N
DA-003
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
96.11h 0.0024mm/h 38.15h 1.551mm
Time-deflection curve & Time-deflection rate curve (T=600OC F=500N)
0.001
0.01
0.1
1
10
100
1000
0
0.5
1
1.5
2
2.5
0 20 40 60 80 100 120
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
-
19
Sample: F92 DA-004 (600OC, 550N)
F92 DA-004 (600OC, 550N)
T=600OC
F=550N
DA-004
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
52.13h 0.0046mm/h 19.32h 1.198mm
Time-deflection curve & Time-deflection rate curve (T=600OC F=550N)
0.001
0.01
0.1
1
10
100
1000
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 10 20 30 40 50 60
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
-
20
Sample: F92 DA-007 (650OC, 450N)
F92 DA-007 (650OC, 450N)
T=650OC
F=450N
DA-007
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
12.12h 0.037mm/h 5.548h 1.656mm
Time-deflection curve & Time-deflection rate (T=650
OC F=450N)
0.01
0.1
1
10
100
1000
0
0.5
1
1.5
2
2.5
0 2 4 6 8 10 12 14
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
-
21
Sample: F92 DA-008 (600OC, 600N)
F92 DA-008 (600OC, 600N)
T=600OC
F=600N
DA-008
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
34.09h 0.007mm/h 13.30h 1.098mm
Time-deflection curve & Time-deflection rate (T=600
OC F=600N)
0.001
0.01
0.1
1
10
100
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 5 10 15 20 25 30 35 40
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
-
22
Sample: F92 DA-009 (650OC, 300N)
F92 DA-009 (650OC, 300N)
T=650OC
F=300N
DA-009
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
197.7h 0.002mm/h 86.98h 0.925mm
Time-deflection curve & Time-deflection rate (T=650
OC F=300N)
0.001
0.01
0.1
1
10
100
1000
0
0.5
1
1.5
2
2.5
0 50 100 150 200 250
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
-
23
Annex 2. Test curves and top views of tested samples, N/T F92
Annex 2A. N/T-L samples
Sample: F92 CD-050 (600OC, 500N)
F92 CD-050 (600
OC, 500N)
T=600OC
F=500N
CD-050
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
26.75h 0.016mm/h 13.51h 1.472mm
Time-deflection curve & Time-deflection rate (T=600OC F=500N
0.01
0.1
1
10
100
1000
0
0.5
1
1.5
2
2.5
0 5 10 15 20 25 30
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
-
24
Sample: F92 CD-046 (600OC, 550N)
F92 CD-046 (600OC, 550N)
T=600OC
F=550N
CD-046
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
14.78h 0.030mm/h 7.109h 1.607mm
Time-deflection curve & Time-deflection rate (T=600OC F=550N)
0.01
0.1
1
10
100
0
0.5
1
1.5
2
2.5
0 2 4 6 8 10 12 14 16
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
-
25
Sample: F92 CD-051 (600OC, 550N)
F92 CD-051 (600OC, 550N)
T=600OC
F=550N
CD-051
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
12.35h 0.031mm/h 5.988h 1.509mm
Time-deflection curve Time-deflection rate (T=600OC F=550N)
0.01
0.1
1
10
100
1000
0
0.5
1
1.5
2
2.5
0 2 4 6 8 10 12 14
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate mm/h)
-
26
Sample: F92 CD-048 (600OC, 600N)
F92 CD-048 (600OC, 600N)
T=600OC
F=600N
CD-048
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
3.610h 0.129mm/h 1.789h 1.484mm
Time-deflection curve & Time-deflection rate (T=600OC F=600N)
0.1
1
10
100
1000
0
0.5
1
1.5
2
2.5
0 0.5 1 1.5 2 2.5 3 3.5 4
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
-
27
Annex 2b. N/T-R samples
Sample: F92 CT-010 (650OC, 300N)
F92 CT-010 (650OC, 300N)
T=650OC
F=300N
CT-010
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
147.14h 0.0024mm/h 59.99h 1.351mm
Time-deflection curve & Time-deflection rate (T=650OC F=300N)
0.001
0.01
0.1
1
10
100
1000
0
0.5
1
1.5
2
2.5
0 20 40 60 80 100 120 140 160
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
-
28
Sample: F92 CT-006 (650OC, 350N)
F92 CT-006 (650OC, 350N)
T=650OC
F=350N
CT-006
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
56.11h 0.006mm/h 29.34h 1.487mm
Time-deflection curve & Time-deflection rate (T=650OC F=350N)
0.001
0.01
0.1
1
10
100
1000
0
0.5
1
1.5
2
2.5
0 10 20 30 40 50 60
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
-
29
Sample: F92 CT-009 (600OC, 500N)
F92 CT-009 (600OC, 500N)
T=600OC
F=500N
CT-009
RUPTURE TIME
MIN DEFLECTION RATE
TIME AT MIN DEFLECTION
RATE
DEFLECTION AT MIN
DEFLECTION RATE
38.27h 0.0104mm/h 16.59h 1.489mm
Time-deflection curve & Time-deflection rate (T=600OC F=500N)
0.01
0.1
1
10
100
0
0.5
1
1.5
2
2.5
0 10 20 30 40 50
de
fle
ctio
n r
ate
(m
m/h
)
de
fle
ctio
n (
mm
)
time (h)
deflection (mm) deflection rate (mm/h)
-
30
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-
31
KJ-N
A-2
9360-E
N-N
doi:10.2760/12580
ISBN 978-92-79-93959-4