Transcript
KSME
International Journal,
Effect
No. J, pp.
lJ-J8.
Temperature
2000
11
Frac Fr actu ture re
Chang-Sun Chang-Sun Se Seok ok (Sungkyunkwan University)
Frac Fractu ture re ough ough
ss
er orme orme
600'C, C, an temper temperatur atur ranging ranging from from -160'C to 600' n lo lo ad ad in in g m pl pl i an
carb carbon on
plat plat
naly nalyze ze acco accord rdin in J -i -i nt nt eg eg ra ra l
ITCT
rela relati tion on o n l ud ud e ur ductil ductile-b e-brit rittle tle trans transit ition ion temp temper erat atur ure, e, an
-IS'C re
decr decr ased ased incr increa easi sing ng temp temper erat atur ure. e. mate materi rial al arou around nd -30·C. decre decreasi asing ng temper temperatu ature re wa signi signifi fica cant. nt.
Key Words:
duct ductil il brit brittl tl tran transi siti tion on temp temper erat atur ur of the - 3 0 ' C , th tende tendency ncy decrea ease se it Ie to decr
J-Inte J-Integra gral, l, Fractu Fracture re Toug Toughn hnes ess, s, Tempe Tempera ratur tur
ffec ffect, t, DBT
ment
J-int J-integ egra ral( l(Ri Rice ce
plas plasti ti
Intr Introd oduc ucti tion on deve develo lo Elas Elasti ticc-pl plas asti ti
frac fractu tu
tempe tempera ratu ture re data fractur tur toug toughne hness ss paramete paramete whic whic defi define ne IC frac
toug toughn hnes ess, s,
ther therma ma
an
of
pe
ur temp temper erat atur ure. e.
Jun temp temper erat atur ur te
these
19
Ther Theref efor ore, e, dete determ rm ne
eval evalua uati tion on
re
values es at re valu
transi transitio tio
shelf an tran transi siti tion onal al toug toughn hnes es sson sson Th objec objectiv tiv pape pape effect of temp temper erat atur ur
(Joy (Joyce ce
elas elasti ticc-pl plas asti ti le
de igni igning ng
such
frac fractu ture re
perf perfor orme me
temp temper erat atur ur
systems.
transinon mate ia construction. Th mate ns io pari pariso so in mu
temperature hose hose
2. Fracture Toughness Test
that that
e no no u temp temp atur atur
un tion tion of he degr degree ee tole tole te he DBTT dete determ rm ne es gnin gnin of mechanical
pe a rb rb o th normal normaliz ized ed conditi condition on ha be uc
pl
used used ex ensi ensive ve
io
cons constr truc ucti tion ons. s. (Fra (Franco ncois, is, 1986 1986 With With th adva advanc nceeCorres Correspon pondin din Autho Author, r, E-mail:
[email protected] TEL: +82-331-290-7477; FAX: +82-331-290-7482 u n k yu yu n a n nive nivers rsit ity, y, 30 Chunch Chunchunun-don dong, g, Jang Jangan an-g -gu, u, uwon uwon Kyon Kyongg ggii-do do (Man (Manus uscr crip ip Febr Februa uary ry 27 999; 999; evis evis ctob ctober er 999) 999)
s ho ho w
Table
Tabl Tabl
y.
orie orient ntat atio io st nd of 'W
0.2S
12
Chang-Sung Table
Chemical compositio of A516 Or70 (wt %)
0.24 1.07 0.013 0.00 0.06 0.035 0.20 0.38
0.21
Ta le
ec anical rp rtie
A516 Or70
Temperature Tensil Strength Yiel Strength
rc:
628
-3
Orientatio of specimen
Elongation(%)
451
2.2 Test procedure Fracture
18
ed
c ed u ture rangin from -160·C to 00·C 10
598
20
569
200
ductile-to-brittle transition
549
373
29
363
31
27
400
34 600
hich covers
441
uppe
of
160·C
lOO·C
is ac me
~ T ~ 6 0 0 · C .
C at al o uall
temperat re environm ntal chambe
temp ra ur pa er lc performe exte omet spli contro encl in electrically te spli
63
tempera Temperatur mount
_._f-
the
unit:mm Sp
CO
U'l
mately a j W = 0 .
20·C and lOO·C. Figure the CO sche atic diagra temperat re
_._.
HC te ting system bser th uctile brittl transitio temp r unit:mm
h ig h temperature extensometer
specimen
Fig.
Specimen we
·C with self-adaptive
ig temperatur extensometer wa mounted th speci
gage
SO.8
S p c im e
controlled to better than temperature controllers
otched to an initia where 'a
jW rati
te
performe
-160·C
temperatur in
temperatur temperatur
environmenta chamber. Figure
ti diagra atur fractu toughnes te ti ystem. Afte atig precrackin at room temperature,
Effect
Temperatur on th Fracture Toughnes
re uction
of
13
Gr
carrie
dynami universa testin machin at test tempera loadin interr pted unloadings(Smith riest, 986) an autographi re or
an
load-line displacement ea te t, pecime
ofload
obtained were om letely
6 - 1 2 . Result
hown crac directly from th fractured surface. Al procedures
with -15'C, O' 0' an IOO'C are 13-16. T ab l le values of R-curves [J C,(t.a) C2
obtained -160'C
HIGH
dWPERATlm
ENSG'1ETER
-30'C,
ri
ad ng
to
ct th de
SPECIMEN
ig
was
Il.
calc late
01
I)
J Q = ~ ( 2 + 0 . 5 2 2 ~ )
load-lin with high temperatur extensometer
em inin 500
i'
<400
380
zoo
-\
Te.p. 1110
ig system
10'C
114 k N / .
CRACKEXTENSION
ig
J-,1 cu vefo A516Gr7 stee with hi temperature extens meter at 20' 500
408 380
1110
-\
emp.
100
100'C
103 kN/m
CRACKEXTENSION
ig testing system
J-,1 curv or A5 Gr teel with ig temperatur extensometer at lOO'C
14
1:1
Chang-Sun
eo
500
580
400
40Q
300
300 1:1
101
100
p.
100
91
.:,
108·C tNt.
100 ••
100
CRACKItXTINSION
curv fo A5l6 temperature extensometer at 500·
J - ~ a
J - ~ a
temperature extensometer at 200· r - - - - r " " T T " - - - - - - . , - - - - ....
400
300
34MI
.: 3 0 0 · C
9.
J,e:
th
5OOr----r--n--------,----,
400
100
500·C
J,e: 85 Nt
CRACKItXTINSION
580
p.
.:,
Te p.
tN
,e
CRACKItXTINSION
CRACKEXTENSION
J - ~ a
Fig. 12
temperature extensomete at 300·
80
600·C tNt.
....
J - ~ a
temperature extens mete at 600·
5OOr----r-rr------,------, 500
400 400
300
p. J,e:
100
400·C tNt.
Te p.
180
-15·C
J,c: 113 tN
CRACKEX'1'I'.NSION CRACKEXTENSION
temperature extens mete at 400·
curv fo A5l6
J - ~ a
Results
the fracture toughness parameter
-15·C
IC
versus t h t em p er at u r a r e s u mm ar iz e in Table 4. th -IOO·C
t em pe ra tu re s r an gi n
to - 3 0 · C , th
specimen
were broken
after some ductile deformation. However, - 13 0 C ,
- 14 0 C ,
-150·C
an
from
-160·C
th
tests,
brittle fracture occurred withou ductile deforma-
tion at maximum load.
v al u v al ue s u si n (Rice, 1968)
th
then calculated following conversion equation.
Effect
Temperatur on th Fracture Toughnes
500
16
r7
15
150 119
4811
~ l i l a
90
380 100
..
Te.p.
108
60
El WIlH COD GAGE
(;)WIT
30
O'
J,c: 118 k N / .
HIGH TEMPERATUR EXTENSOMETER
100
300
ZOO
400
TEMPERATURE ("C)
CRACK EXTENSION e.m)
Fig. 14
The effect of temperatur on th uppe shel region of DBTT
J-l!.a curv fo A516 Gr70 stee with CO
Discussion
5OO,..---r-rr--------,-----,
xp
4811
ta
s ho w
l oa d- li n
displacement ca be measured su cessfull by th
308
temp ratu
ome ul
rc
100 Te.p.
101
temp ratu
lO'C
lOO'C, respectively bu
loa
118 kN/m
he
displacement obtained
That
atur extensometer CO
CRACK EXTENSION emm>
Fig. 15
J-l!.a curv fo A5l6 Gr70 stee with CO gage at 20'C
500..---.....,....,.,...-------,------,
gage. Th
ve temperatur dete mine
that temperatures Figure
elasti
toughness,
400
nsome
uppe shel
ductile-brittle transition temperatur BTT) de crease with increasing temperature. Th IC value
300
follows:
ZOO
Te.p.
100
J.
100' C
f l c = - O . 0 6 T + 115
kN/.
te pe CRACKEXTENSION
J-l!.a curv fo gage at loo'
A516
u r [ 'C ]
elastic-plasti fracture toughness[kN/m].
Gr70 stee with CO uppe shel temperature. Th
(2) temp summ ri ed
(3)
C, (
tu
L ~ a )
ductile-brittle transition R-curve
C,] 88
Tabl
ha while C, slightly reaching essentiall constant IC
in reas
initiall
Chang-Sun
16 effect of temperatur on
Test Method
Temperature R-Curve [j
rc:
-rrrrrr.:
IC
CdLla) C,]
11C
51
Toughnes
suppor provided Engineering tructu al Sungkyunkwan
References
transition Francois D.
le
ignificant
986, "Relation betwee Vari us
te
dency transitio temperature behavior of frac ture toughnes as similar to th re ults of others. Watainab
Fracture Toughnes Transitio Curve, Engineer in Fracture Mechanics, Vol. 3, No.2,
to
" Ch ar ac terization of Transition Temperature Be avio of IC Fracture Toughnes Parameter,"
160·C
temperatur
-IYC,
correlated as ollows 4000 (T-15)
10
-465.
(4)
417-430.
K. L., 1988 "Effec of
temperaturej't J, Fracture Behavior Vessel Steel, A S T M STP969 pp 392-401.
ue[kNjmJ.
Conclusion Th
ollowi
conclusion were obtained fr
ASTM
150-165.
18
Chang-Sun
,"Fracture oughness Frac ur Ni-Fe-Cr Alloys," Engineerin Mechanics, No.2, pp. 223-228. Mahmood, L. Irradiated Partiall Denitrided 422-430. Mild Steel, ASTM L., 999, "Role nd ignificanc of Sour Hardenin in Radiation Embrittlemen of Journal Nuclear I ro n Materials 270, pp 115-128. Unloading Compliance thod fo Crac ng re ompact Tensio cracke Charp Sp mens," ASTM pp. 375- 393. "A Path Independent Integral Approximat Journal Applied Mechanics, 379-386. V. 1988, "Determination
ok
of Material Characteristic Values in Elastic-Plas J -I n g r Testing ra sist nc urve," Journal an Evaluation I-II. Leng Me sure en by Compliance Fracture Toughnes Testing, Experimental Mechanics, pp. 122-127. Yo obor "Fractur ough Engi ee in Frac ur T ra ns it io n gi n, Mechanics, 589-600. S t n da r le Fracture oughness," A nn ua l ASTM Standards, Strain Fracture Toughness of Metallic Materials, Annual ASTM Standards, 399-90.
