Determination of Reference Temperature T0 for Steel JRQ in an Unirradiate State and Construction of Master curve
The paper considers the results of testing reactor steel JRQ involving determination of the crack-growth resistance and the reference temperature To, construction of Master Curve, and evaluation of the boundaries of the regions with different failure probability. The tests were conducted on sm...
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Інститут проблем міцності ім. Г.С. Писаренко НАН України
2002
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| Назва видання: | Проблемы прочности |
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| Цитувати: | Determination of Reference Temperature T0 for Steel JRQ in an Unirradiate State and Construction of Master curve / A. Ballesteros, V.A. Strizhalo, E.U. Grinik, L.S. Novogrudskii, L.I. Chirko, and M.P. Zemtsov // Проблемы прочности. — 2002. — № 1. — С. 41-51. — Бібліогр.: 5 назв. — англ. |
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irk-123456789-467282016-04-14T10:31:47Z Determination of Reference Temperature T0 for Steel JRQ in an Unirradiate State and Construction of Master curve Ballesteros, A. Strizhalo, V.A. Grinik, E. U. Novogrudskii, L.S. Chirko, L.I. Zemtsov, M.P. Научно-технический раздел The paper considers the results of testing reactor steel JRQ involving determination of the crack-growth resistance and the reference temperature To, construction of Master Curve, and evaluation of the boundaries of the regions with different failure probability. The tests were conducted on small specimens (1/2T) made from blocks of steel JRQ supplied by the IAEA within the framework of the Round Robin program. Рассмотрены результаты исследования трещиностойкости корпусной реакторной стали JRQ и построена зависимость коэффициента интенсивности напряжений от температуры (—196...+50С), которая является так называемой "Master curve”. При исследовании вязкости разрушения использовали малые компактные образцы толщиной 1/2T, которые вырезали из заготовки стали JRQ размером 225Х198Х 165 мм, поставленной МАГАТЭ. Испытания проводили в соответствии со стандартом ASTM E 1921-97 "Determination of Reference Temperature T0 for Ferritic Steels in the Transition Range”. Для уточнения температуры T0 и выполнения необходимых расчетов проводили также испытания на ударную вязкость и динамические испытания по определению модулей упругости E и G в интервале температур —196 ...+350°С. Построена "Master curve” по результатам испытаний двух типов компактных образцов на различном оборудовании и определены ее доверительные интервалы для различных вероятностей. Розглянуто результати дослідження корпусної реакторної сталі JRQ і побудовано залежність коефіцієнта інтенсивності напружень від температури (—196... + 50°C), яка є так званою “Master curve”. При дослідженні в ’язкості руйнування використовували малі компактні зразки товщиною 1/2T, що вирізали з поставляємої МАГАТЕ заготовки сталі JRQ розміром 225 X 198 X 165 мм. Випробування проводили у відповідності до стандарту ASTM E 1921-97 “Determination of Reference Temperature To for Ferritic Steels in the Transition Range”. Для уточнювання температури To і виконання необхідних розрахунків випробування по визначенню модулей пружності E і G в інтервалі температур -196 ...+ 350°C. Побудовано “Master curve” за результатами випробувань двох типів компактних зразків на різному обладнанні і визначено її довірчі інтервали для різних імовірностей. 2002 Article Determination of Reference Temperature T0 for Steel JRQ in an Unirradiate State and Construction of Master curve / A. Ballesteros, V.A. Strizhalo, E.U. Grinik, L.S. Novogrudskii, L.I. Chirko, and M.P. Zemtsov // Проблемы прочности. — 2002. — № 1. — С. 41-51. — Бібліогр.: 5 назв. — англ. 0556-171X http://dspace.nbuv.gov.ua/handle/123456789/46728 539.4 en Проблемы прочности Інститут проблем міцності ім. Г.С. Писаренко НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| topic |
Научно-технический раздел Научно-технический раздел |
| spellingShingle |
Научно-технический раздел Научно-технический раздел Ballesteros, A. Strizhalo, V.A. Grinik, E. U. Novogrudskii, L.S. Chirko, L.I. Zemtsov, M.P. Determination of Reference Temperature T0 for Steel JRQ in an Unirradiate State and Construction of Master curve Проблемы прочности |
| description |
The paper considers the results of testing reactor
steel JRQ involving determination of the
crack-growth resistance and the reference temperature
To, construction of Master Curve, and
evaluation of the boundaries of the regions with
different failure probability. The tests were conducted
on small specimens (1/2T) made from
blocks of steel JRQ supplied by the IAEA
within the framework of the Round Robin program. |
| format |
Article |
| author |
Ballesteros, A. Strizhalo, V.A. Grinik, E. U. Novogrudskii, L.S. Chirko, L.I. Zemtsov, M.P. |
| author_facet |
Ballesteros, A. Strizhalo, V.A. Grinik, E. U. Novogrudskii, L.S. Chirko, L.I. Zemtsov, M.P. |
| author_sort |
Ballesteros, A. |
| title |
Determination of Reference Temperature T0 for Steel JRQ in an Unirradiate State and Construction of Master curve |
| title_short |
Determination of Reference Temperature T0 for Steel JRQ in an Unirradiate State and Construction of Master curve |
| title_full |
Determination of Reference Temperature T0 for Steel JRQ in an Unirradiate State and Construction of Master curve |
| title_fullStr |
Determination of Reference Temperature T0 for Steel JRQ in an Unirradiate State and Construction of Master curve |
| title_full_unstemmed |
Determination of Reference Temperature T0 for Steel JRQ in an Unirradiate State and Construction of Master curve |
| title_sort |
determination of reference temperature t0 for steel jrq in an unirradiate state and construction of master curve |
| publisher |
Інститут проблем міцності ім. Г.С. Писаренко НАН України |
| publishDate |
2002 |
| topic_facet |
Научно-технический раздел |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/46728 |
| citation_txt |
Determination of Reference Temperature T0 for Steel JRQ in an Unirradiate State and Construction of Master curve / A. Ballesteros, V.A. Strizhalo, E.U. Grinik, L.S. Novogrudskii, L.I. Chirko, and M.P. Zemtsov // Проблемы прочности. — 2002. — № 1. — С. 41-51. — Бібліогр.: 5 назв. — англ. |
| series |
Проблемы прочности |
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2025-07-04T06:10:38Z |
| last_indexed |
2025-07-04T06:10:38Z |
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| fulltext |
UDC 539.4
D e te rm in a tio n o f R efe ren ce T e m p e ra tu re T0 fo r S teel J R Q in an
U n ir ra d ia te d S ta te a n d C o n s tru c tio n o f M a s te r C u rv e
A. Ballesteros,a V. A. Strizhalo,b E. U. G rinik,c L. S. Novogrudskii,b L. I.
Chirko,c and M. P. Zemtsovb
a Tecnatom S.A., Madrid, Spain
b Institute of Problems of Strength, National Academy of Sciences of Ukraine, Kiev,
Ukraine
c Scientific Center “Institute for Nuclear Research,” National Academy of Sciences of
Ukraine, Kiev, Ukraine
УДК 539.4
О п р е д е л е н и е э т а л о н н о й т е м п е р а т у р ы T0 д л я с т а л и J R Q и
п остроен и е “ M a ste r c u rv e ”
А. Баллестероса, В. А. С триж ало6, Э. У. Г риникв, Л . С. Н овогрудский6,
Л. И. Ч и рков, М. П. Земцов6
а “Tecnatom S.A.”, Мадрид, Испания
6 Институт проблем прочности НАН Украины, Киев, Украина
в Научный центр “Институт ядерных исследований” НАН Украины, Киев, Украина
Рассмотрены результаты исследования трещиностойкости корпусной реакторной стали
JRQ и построена зависимость коэффициента интенсивности напряжений от температуры
(—196...+50С), которая является так называемой "Master curve”. При исследовании вяз
кости разрушения использовали малые компактные образцы толщиной 1/2T, которые выре
зали из заготовки стали JRQ размером 225Х198Х 165 мм, поставленной МАГАТЭ.
Испытания проводили в соответствии со стандартом ASTM E 1921-97 "Determination of
Reference Temperature T0 for Ferritic Steels in the Transition Range”. Для уточнения темпе
ратуры T0 и выполнения необходимых расчетов проводили также испытания на ударную
вязкость и динамические испытания по определению модулей упругости E и G в интервале
температур —196 ...+350°С.
Построена "Master curve” по результатам испытаний двух типов компактных образцов на
различном оборудовании и определены ее доверительные интервалы для различных веро
ятностей.
К л ю ч е в ы е с л о в а : вязкость разрушения, температура вязко-хрупкого пере
хода, J -интеграл, “Master curve”, прочность.
Introduction. The known methods for obtaining reliable data on fracture
toughness under conditions of plane deformation require tests to be conducted on
long specimens and involve high consumption of hard-to-get materials. For
reactor steels, for which it is necessary to determine the transition temperature
© А. БАЛЛЕСТЕРОС, В. А. СТРИЖАЛО, Э. У. ГРИНИК, Л. С. НОВОГРУДСКИЙ, Л. И. ЧИРКО,
М. П. ЗЕМЦОВ, 2002
ISSN 0556-171X. Проблемы прочности, 2002, N2 1 41
A. Ballesteros, V. A. Strizhalo, É. U. Grinik, et al.
shift in the irradiated state as compared to the unirradiated one, the use of
large-size specimens is unacceptable at all, and surveillance specimens are small
in size and their tests involving the methods of nonlinear fracture mechanics are
rather labor consuming and expensive. Employing Master Curve approach for
ferritic steels enables obtaining reliable data and the temperature dependence of
the crack-growth resistance variation at the lower boundary of transition over the
wide temperature range by testing small specimens [1]. According to the recent
standardizing documents, Master Curve is constructed on the basis of the results
of testing small-size specimens at a single temperature value such that slow
steady growth of a crack before the beginning of instability is practically
precluded. This makes it possible to simplify considerably the procedure for
determining the /-integral and to use the experimental basic approach of
nonlinear fracture mechanics. Below we consider the results of determining the
reference temperature T0 and constructing Master Curve on the basis of the
experiments performed for reactor steel in an unirradiated state.
M aterial and Specimens. Compact-tension specimens for the construction
of Master Curve and standard Charpy specimens for the determination of
brittle-to-ductile transition temperature were fabricated from blocks of steel JRQ
with dimensions of 225 X 198 X165 mm, its chemical composition is given in
Table 1.
T a b l e 1
Chemical Composition of Steel JRQ
C Si Mn Ni Mo Cr P Cu S Al V
0.18% 0.24% 1.42% 0.84% 0.51% 0.12% 0.017% 0.14% 0.004% 0.014% 0 .002%
For static fracture toughness tests we used 1/2T CT specimens of two types
(Fig. 1), whose orientation corresponded to the T-L direction [2] of the JRQ steel
billet. These specimens differed in dimensions and design of the attachment
points of the displacement transducer. Specimens of the second type had side
notches made after growing an initial fatigue crack (see Fig. 1b). The dimensions
of the second type specimens corresponded to those of the surveillance specimens
installed in reactor pressure vessels of the nuclear power plants in Ukraine.
Specimens of these two types were tested to assess how differences in dimensions
and design affect the magnitude of the reference temperature and the trend of
Master Curve for steel JRQ in an unirradiated state. Fracture toughness tests were
performed in accordance with [1] at a temperature of T28 j — 28. The temperature
T28 j was determined from the results of testing Charpy specimens (10 X 10 X 55
mm) using a two-column pendulum impact testing machine with a store of impact
energy 300 J in the temperature range from — 196°C to +270oC.
The first type specimens (see Fig. 1a) were tested at a conventional
laboratory of the Institute of Problems of Strength of the National Academy of
Sciences of Ukraine using Instron-1126 testing machine with a hydromechanical
converter with an ultimate load of 250 kN that allowed us to perform both stress-
and strain-controlled tests. Most of the second type specimens was tested using an
electromechanically driven Instron-8500 testing machine with an ultimate load of
100 kN equipped with remote control and installed in a hot chamber of the
42 ISSN 0556-171X. Проблемы прочности, 2002, N 1
Determination o f Reference Temperature
Institute for Nuclear Research of the National Academy of Sciences of Ukraine to
correspond to the requirements of the ENUCRA program (see Fig. 1b). Only
some of those specimens were tested in the Instron-1126 testing machine for
comparison.
12.7
50
10
12
1/2 T CT
b
Fig. 1. Dimensions of 1/2T CT specimens of the first (a) and second (b) types in mm.
a
In impact toughness testing the specimens were heated in an electrical
resistance furnace, and cooled in a mixture of liquid nitrogen with alcohol. In
fracture toughness testing using the Instron-1126 testing machine 1/2T CT
specimens were cooled in a cryogenic chamber also using the mixture of liquid
nitrogen with alcohol (see Fig. 1a), specimens of the second type tested in the hot
chamber on the Instron-8500 testing machine were cooled in the vapors of
nitrogen (see Fig. 1b). Both methods of cooling allowed obtaining a stable low
temperature in the range under study.
ISSN 0556-171X. npo6n.eubi npounocmu, 2002, № 1 43
A. Ballesteros, V. A. Strizhalo, H. U. Grinik, et al.
The temperature was measured with thermometers and thermal converters,
which had been put to metrological tests. For measuring loads and crack opening
displacement, elements of the measurement systems (devices, gauges, and
transducers) of the Instron testing machines were used that allowed determining
loads and displacements to a high accuracy, and obtaining reliable P — V
diagrams. The procedure for measuring temperature, load and displacement, and
also the technique for growing initial fatigue cracks met the requirements of [1].
To get a deep insight into the mechanical behavior of the steel investigated
over the operating temperature range, and to obtain data on strength and elasticity
characteristics essential in the determination of the load causing initial fatigue
crack, and the limiting value of K j c and its current values with respect to the
./-integral values, short-term strength tests were performed with an Instron
testing machine and elasticity was determined by the dynamic method with the
use of a special resonant equipment [3].
When testing short-term strength, standard five-fold specimens were
employed with the working section 10 mm in diameter and 50 mm in length. The
modulus of elasticity E and shear modulus G were found for cylindrical
specimens 8 mm in diameter and 120 mm in length from their resonance
frequency in bending and torsional vibrations, respectively.
Construction of M aster Curve. The Master Curve concept is based on the
results of fundamental investigations performed by Wallin [4, 5] and involves the
following principles:
- probability of brittle fracture P f for a specimen chosen arbitrarily from
the batch is described by a three-parametric equation of Weibull [4]:
P f = 1 — exp
( K — K \ 4
Ic min
K 0 K min j (1)
where K 0 is the scale parameter, whose magnitude is governed by the specimen
thickness and test temperature, and K min is the least crack-growth resistance,
whose magnitude according to [1] is assumed to be equal to 20 MPaVm;
- the level of the crack-growth resistance depends on the specimen thickness
and this relationship is described by the following formula [5]:
K B Y
B
1/4
(2 )
X Ywhere K ic and K i c are the values of the stress intensity factors for specimens
of thickness B x and B y at the same probability of brittle fracture P f ;
- the median value of the crack-growth resistance (at P f = —0.5) as a
function of the temperature for 1T CT specimens is described by the equation,
which is the equation of Master Curve [1]:
K/c(m ed) - 30+ 70exp[0.019(T — T0 )], (3)
44 ISSN 0556-171X. npo6n.eubi npounocmu, 2002, № 1
Determination o f Reference Temperature
where T0 is the reference temperature at which K j c(med) is taken to be equal to
100 MPaVm [1].
Using Eqs. (1)-(3) for specimens of any thickness at any fracture probability
temperature dependences of the crack-growth resistance can be calculated from
the results of testing the material for crack-growth resistance at a single
temperature value. The procedure of such tests and regulating requirements for
them are described in detail in [1]; they were used for obtaining the data
considered in the present study.
The temperature at which the fracture toughness tests were performed was
defined as
where C = -28°C for 1/2T specimens, and the temperature T28j , as noted above,
was determined from the results of impact toughness testing the Charpy
specimens. The data obtained from such tests for the specimens with the L-T
(along the rolling direction) and T-L (across the rolling direction) orientations are
given in Fig. 2. As follows from these results, a considerable scatter of the impact
toughness values is observed in the region of the brittle-to-ductile transition, that
is indicative of instability of the property of the JRQ steel billet to resist brittle
fracture that was also confirmed by the results of fracture toughness tests. The
T28 j value was determined for the T-L orientation and amounted to — 52°C. Thus,
the crack-growth resistance tests according to the guidelines of [1] and on the
basis of Eq. (4) should be carried out at the temperature T = — 80°C.
T = T28 j + C , (4)
200
®
A .
1 - T-L orientation
2 - L-T orientation
0
-200 -150 -100 -50 0 50 100 150 200 250 300
Temperature (°C)
Fig. 2. Results of Charpy testing of unirradiated JRQ material.
ISSN 0556-171X. npo6n.eubi npounocmu, 2002, № 1 45
A. Ballesteros, V. A. Strizhalo, É. U. Grinik, et al.
To calculate the limiting value of the stress intensity factor at this
temperature we used equation
K Jc(limit) = V E b 0 O y I 30, (5 )
where E is the modulus of elongation, b0 is the ligament of the compact
specimen b0 = W — a 0 , and O y is the yield strength of the material at this
temperature. The mechanical characteristics of JRQ steel obtained for the
operating temperature range are given in Table 2, and the temperature
dependences of the moduli E and G are illustrated in Fig. 3.
T a b l e 2
Mechanical Characteristics of Steel JRQ
Temperature, OC Ultimate strength
a u, MPa
Yield strength
aY, MPa
Residual elongation
ô,%
20 640.0 490.0 18.0
— 80 790.0 630.0 18.5
— 196 990.0 960.0 0.5
E, MPa • 10 5 G , MPa -10 5
2.25
-200 -100 0 100 200 300 400
Temperature ( C)
Fig. 3. Temperature dependences of the elasticity and shear moduli E and G.
It should be emphasized that the break of monotonicity of the curve trend
was observed for the elastic modulus E in the region of the brittle-to-ductile
transition temperatures that is indicative of abnormal changes in the structure of
the material in this region as the temperature decreases.
For the values of E and Oy obtained at — 80°C, K Jc(1imit) = 233.0 MPaVm.
46 ISSN G556-Î7ÎX. Проблемыг прочности, 2GG2, № Î
Determination o f Reference Temperature
1/2T CT specimens were tested in the mixture of liquid nitrogen with alcohol
or vapors of nitrogen at — 80oC with a simultaneous recording of P — V diagrams.
From the results of processing the diagrams we determined the values of the
J -integral as a sum of its elastic and plastic components:
J c J e + J p . (6)
The elastic and plastic components were defined as
and
У = K l
e E
r =
J p B b 0
(7)
(8)
respectively, where K e is the value of the stress intensity factor determined by
the known procedure [1], ^ is the coefficient dependent on the dimensions of the
CT specimen bo and W , A p is the work of plastic deformation determined from
the corresponding area of the P — V diagram, and B is the specimen thickness.
The quantity K jc was calculated for each individual specimen depending on
the particular J c value from the relation
K Jc = VJ cE . (9)
The values of J c and K j c for qualification specimens of two types, which
remained after the rejection performed according to the requirements of the
standard [1], are listed in Tables 3, 4.
T a b l e 3
The Values of Crack-Growth-Resistance Characteristics for the First Type Specimens
at T = — 80°C
No 1 2 3 4 5 6 7 8
Jc, kJ/m2 8.45 31.0 32.5 41.8 51.7 21.5 34.3 86.9
KJc, MPaVm 43.00 82.5 84.6 95.9 106.6 68.6 84.9 58.3
T a b l e 4
The Values of Crack-Growth-Resistance Characteristics for the Second Type Specimens
at T = -80°C
No 1 2 3 4 5 6 7 8* 9*
Jc, kJ/m2 23.7 27.2 68.1 22.3 14.1 28.6 16.5 25.1 50.0
K jc, MPaVm 72.2 77.4 122.4 70.1 55.6 75.6 60.2 74.1 104.9
* Specimens 8 and 9 were tested in the Instron-1126 testing machine using the mixture of alcohol
with liquid nitrogen.
ISSN 0556-171X. Проблемы прочности, 2002, N2 1 47
A. Ballesteros, V. A. Strizhalo, É. U. Grinik, et al.
Master Curve was constructed and the temperature T0 was determined for
the 1T specimens. For this reason, on the basis of the data given in Tables 2 and 3,
K 0 and K j c(med) were determined successively for specimens of thickness 1/2T
and 1T from Eqs. (1) and (2). Below are given their values for the specimens of
the first type:
8
K 0(1/2T)
2 (K M i) - 2 0 )
i=1
N - 0.3068
1/4
+ 20= 86.4 MPaVm,
K 0(1T) = 20 + [K0(1/2T) - 20]
j \ 1/4
B i
\ B (1T)
= 75.8 MPaVm,
K
1
Jc(1T)(med ) 4= t [ K 0(1T) - 2 0 ][ln(2 )] + 2 0 = 70.9 MPaVm,
and for the specimens of the second type:
K 0(1/2T)
2 (K jc ( i) - 2 0 )
i=1
9 - 0.3068
1/4
+ 20= 90.1 MPa Vm,
K 0(1T) = 20 + [K0(1/2T) - 20]
I \ 1/4
B i
\ B (1T)
= 74.9 MP^Vm,
K ,
1
= t [K 0(1T) - 20][ln(2)]+ 20= 70.6 MP^Vm.Jc(1T)(med) 4 i
The magnitude of the reference temperature was determined from Eq. (3):
Tn = T -
1
0.019
ln
K Jc(1T)(med) - 30
70
where T = - 8 0 oC.
We obtained To = —51.70C for the specimens of the first type and
T0 = — 51.30C for those of the second type.
We assumed T0 = — 520C for K j c = 100 MPaVm.
Thus, the final equation of Master Curve for unirradiated steel JRQ has the
form
48 ISSN 0556-171X. npoôëeubi npounocmu, 2002, N2 1
Determination o f Reference Temperature
K Mmed) = 30+ 70exp[0.019(r + 52)]. (10)
Master Curve is depicted in Fig. 4; it is known that this curve corresponds to
the 50% cumulative failure probability. Standard deviations for the T0 value
obtained with allowance for the statistical character of fracture of ferritic steel
JRQ are defined as
3о = (11)
where N is the number of the qualification specimens and 3 is the coefficient
dependent on the magnitude of K j c(med).
Fig. 4. “Master Curve” results obtained using JRQ materials: 1 - specimens I type, Instron-1126; 2 -
specimens II type, Instron-8500; 3 - specimens II type, Instron-1126.
In our case, N = 8 and 3 = 18-8 for K j c(med) = 70.9 MPaVm. Therefore,
for the specimens of the first type, <7 = 6.6°C. For K j c(med ) = 70.6 MPaVm,
N = 9 and 3 = 18.8. Therefore, for the specimens of the second type, o = 6.3°C.
The tolerance bounds are determined from the following equations based on
the use of Eq. (1):
the lower 1% tolerance bound:
Kjc(0.0i) = 23.5 + 24.4exp[0.019(T- T))]; (12)
the lower 5% tolerance bound:
K jc ( 0 .0 5 ) = 25.2 + 36.6exp[0.019(r - 2^)];
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A. Ballesteros, V. A. Strizhalo, Й. U. Grinik, et al.
the upper 95% tolerance bound:
Kjc(0.95) = 34.5 + 101.3exp[0.019(T- 20)]; (14)
the upper 99% tolerance bound:
Kjc(0.99) = 36.1 + 112.8exp[0.019(T- З Д (15)
Figure 4 shows the curves corresponding to the above tolerances that bound
the scatter range of the results of crack-growth resistance testing with a given
failure probability when realizing the method of Master Curve. Within the scatter
range of Master Curve points are marked that correspond to the values of K j c
obtained for 1T CT specimens on the basis of the results of crack-growth testing
1/2T CT specimens of steel JRQ at -50°C, -80°C, - 100°C, - 110°C, and - 196°C.
C O N C L U S I O N S
1. The equation of Master Curve for steel JRQ in an unirradiated state has
the following form:
K jd m e d ) = 30+ 70exp[0.019(T + 52)].
2. Reference temperatures determined for the two types of 1/2T CT
specimens of steel JRQ are little different and amount to -51.7 °C and - 51.3°C, for
the specimens of the first and second types, respectively.
3. The procedure for determining the reference temperature T0 from testing
small 1/2T CT specimens in the hot chamber was developed on the Instron-8500
testing machine within the framework of the ENUKRA program. It gives
repeatable results that agree satisfactorily with those of testing using certified
equipment of high accuracy on the basis of the Instron-1126 testing machine
under comfortable (i.e., without remote control) laboratory conditions. Therefore,
the procedure for fracture toughness testing within the framework of the
ENUCRA program can be treated as efficient and dependable, and the results
obtained employing this procedure can be considered as reliable.
Р е з ю м е
Розглянуто результати дослідження корпусної реакторної сталі JRQ і по
будовано залежність коефіцієнта інтенсивності напружень від температури
(—196... + 50°C), яка є так званою “Master curve”. При дослідженні в ’язкості
руйнування використовували малі компактні зразки товщиною 1/2T, що
вирізали з поставляєм ої М АГАТЕ заготовки сталі JRQ розміром
225 X 198 X 165 мм.
Випробування проводили у відповідності до стандарту ASTM E 1921-97
“Determination of Reference Temperature To for Ferritic Steels in the Transition
Range”. Для уточнювання температури To і виконання необхідних розра
хунків проводили також випробування на ударну в ’язкість та динамічні
50 ISSN 0556-171X. Проблеми прочности, 2002, № 1
Determination o f Reference Temperature
випробування по визначенню модулей пружності E і G в інтервалі темпе
ратур -1 9 6 ...+ 350oC.
Побудовано “Master curve” за результатами випробувань двох типів ком
пактних зразків на різному обладнанні і визначено її довірчі інтервали для
різних імовірностей.
1. A S T M E 1 9 21-97 . Standard Test Method for Determination of Reference
Temperature To for Ferritic Steels in the Transition Range // Annual Book
of ASTM Standards. - 1998. - Vol. 03.01. - P. 1068 - 1084.
2. A S T M E 399-74 . Standard Test Method for Plane Strain Fracture Toughness
of Metallic Materials // Annual Book of ASTM Standards. - 1974. -
Vol. 03.01. - P. 509 - 539.
3. A ll-U n io n S ta te S ta n d a r d 2 5 1 5 6 -8 2 “M etals. Dynamic M ethod for
Determining Characteristics of Elasticity.”
4. W allin K . The scatter in K Ic results // Eng. Fract. Mech. - 1984. - 1 9 .-
P. 1085 - 1093.
5. W allin K . The size effect in K Ic results // Ibid. - 1985. - 22. - P. 149 - 163.
Received 26. 09. 2001
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