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ΤΕΧΝΙΚΟ EfliMΞAHTHFIO EJvWAI. 1

ΓΡΑΦFΙΟ ΠΞΚΜΗΡ!QΣΙ ΙΣ .

CONSE(~UE~~CES OF FI\TE GUILI,O'fINΈ Β1ϊΕΑΙ{S 1Ν KA.RDLι\ 1

FEED WA.TEit. CIRCUTJ.c\ΊΊON PIPli\fG

" λ LECTURE ΒΕ LEAR!~ED

,1. Janslcy ::•, Τ. Papadelis**

~·Iavidis Panos**

President of BTB-Jan;,ky GmbH

Operation Eng. in KARDIA - Po\ver plant

Be presented on symposiιιm: Ugntte and irs energy contιibιιιion to the elecrr. balance 2nd and 3rd October 1992 in Kozanj/Greece S11bsecιion 2

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1. Summary

2. Introdnctίon and Objectives

3. 11areήal Specifications aηά Operating Conditions

4. Cheπucal and Stress Analysίs, tνlcchanical-Technological Testings

5. Sequence of Eνents and Jν1acroscopic Finclings

6. Cn:cp Behaviour at 345°C

7. Remedial measures

8. References

9. Captures

..

..

.· ....

1. ·i

Tl1e t'ced -.v;.ιter ρipe ιη po\vcr p ! ιωt Κλ.Η.D.Ά 1, cper.ated ίιy p :::: 184 bcπ anJ Τ::: 3-tO"C ιυρωred iη five cross sections (gu.illotine brea.ks) afιcr ~ 30 000 qperaύng lωurs.

The bnrst feed pipe of 250 insid.e diarαete; and 18 nυη waΠ ιlιickness inade ο: 15 ΝiCι!ΜοΝΌ 5 (accorιίing to specificat!on 1972) \vas subjccted to

:;; rnechanical-tecr1no1oglcal testing

* stress ana]ys ίs aud

* fracωgraphic analysis

a3 a basis for final frac t.υre n~cchanic assessτnent.

T!1e ίE1aJysis r~utts Γ~νealed t.t-iat th~ state of the material f ound after ιh~ fa ilure of dJe pipe is characteriscιi by 1o\v Jιιcrility. Ιη addition, nurneroιιs π1ater1al micro separa­ιions \Vru ch occurrc'l under opel'atin5 conditions 'Nerc found νιithin individuHI frac­tυrαi cross scctions.

The cίrcυ ntferenrial fracturι:s p:-ιrallel to the circumferential scaω rct;j ~ns started in circumferentially cι ackcd Γegions and wid<:'ned in ducti le manne.r (sheίi_.1 np.) \τιith only 1υ\V cJefoπηation in tl1c fiaα:υred arens. T11e gu.illotine brca.k iu p~rent ~:υιteή~ll srarteJ in an area οη tbe c:Γcumf{'~ϊ·.rιce ·...vhich i1npactcιi the boiler strucαιre . Tlιe r·cst of ιhe fracrure is ductile by shear.

The rema.ining.partial cros3 secdon fractures in the base m<ιterial exhibjι prcdoω..ί­naot1y bήttle- fractures in impacted zones and are oήented perpencticula1·1y to the maί n sιress c4rect:i.on-(longitudina1) . ...

·. ~r .. ·~ ~~~, . = .

The analysi~reveals that fracαιres started in circumferentia1 cracks adjoined to geo­meαical ίmperfecrions in highly.-.stressed pipe cross sections in form uf cι·eep cracks . extension: After the crack reached the cήtical length under sustained loading τbc spΌntaneous rupture fol1owed .

. )

..

' Intvxiuction and Objecιives Ι

.\ mulciple circurnfcrential fracture in tbe section of the feed ρipe in the Benson type Η 6 t/h steam generat~x at ΚARDIA 1 power plant (300 MW el) .ΚΟΖΑΝΙ, Greece )Ccwτed, f~_l.

Γhe plant was put in service in 1974 and has been operated since then for approxi­mately 130,000 hours. During this operation peήod, the plant had 71 cold and 20Ί warrn start-ups.

The fractured part of the feed pipe \Vitb an inside ctiameter of 250 mm and a wall thickness of 18 n1ffi was manufactured from the mateήal 15 NiCuMoNb 5. The fced pipe between the ci.rculation pumps as far as the distributor header wit.1:1 350 outer d.iameter χ 22 mm \Vall thickness and, finally, the ήήg pipe around the boiler \Vitl1

300 Inin outside. cliameter χ 26 mn1 \vall thickness are also made from the material 15 NiCuMΌNb 5.

After the event, fiνe circumferential fractures were fQ.ιιnd. Four of the fractures adjoin the circumferenrial seam regions, one is located in parent mateήal. Circumferentiall)' oriented through-wall cracks with lengths of approx. 200 rrun are located at two cross secιions \Vhich impacted on boiler auxiliaήes.

According to inforrnation from the oρerator, there were no special registered occnr­rences at the άme of the eνent which would inclicate increases in intemal pressure. Νο signs of leakage were observed ίη the region in question of the pipe.

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·~

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.·

3. Material Specificarions and Operaring Conditions

At Lι'Ί~ · moment of the accident ίl1e plant was operated ar an e1cctrica1 outpuc of 240 MWei- The Benson boiler was producίng approx. 816 tJh stcam at a pres:.ure of 174 har and ternperature of Τ = 540°C. The oper:ιting para1neters of the connectinσ

.:>

pipes (feed piρι;) do-wrnstrcam the scparator header wlύ.ch sυρply til·~ Benson fumace walls witίι feed water are specified with Τ = 330 to 345°C and p = 184 bar (iniom:ιation from Public Power Corporarion PPC).

The transi~nt loaι.iings are stated 1Nith

* 71 cold starts a._rιd

* 207 wann starts.

The ΚARDIA po\ver g~nerating btocks are operaιed as base loacl· u..'1.ίts. It cσuld bc concίuded u'"!at cyclica.l s tressίn ·5 ill the region of the cJ.an11ged CI'OSS se · · tior~S ιad ηο imporτant role. Temperature fluctuιιtions in LJ-ιe d.amaged axca can be ex.pected \Vittι a m;wmιnn όf 20 Κ. These temρcrature transients cause alternaιing stress a.mρlitudι:s below th~ fat:igue duration values. They are not significar.t to conτrίbutc to iiιcipi:;nt cτJ.ck foπnatίon. The internal prcssure of 184 bar also remains largely constεϊ1t duήng oper:.ιtion .

. . Ίlιe ch~πιical composίtion anrl mateήa.l specL4i.cati.on according to piping manι:f acτuτcr is listed 1n fu~-2. ·

The reference stresses of υΊe cήtical cross secrion at tbe T-piece wit11 tlι~ w<11l thick­ness of 13.75 mm, fj~ure 3, resulιing from interual pressure can be deteπη.ίned \V i tι.'1 177 N/πun2• .

-The secondary stresses can b~ det~rmined from theπηally induced displacemenιs of the systems adjΌining ·the pip~. The moνement of tlιe furnace plays a decisive role \Vith regard to the loading i11 the feed pipe. The νertically posirioned furnace is susρended within the boiler frame structure, figure 4. The theπnally induced expansion of the boiler walls, therefore, takes p1ace in a downward direction towards the base of tl1e strucαιre. This expansion has been measured by the operator witl1 280 ηιm

. Vertically positίoned feed pipes between the separator (fixed point within boiler fnιme stnιcture) and the ήng main will expand in the same direction being heated to 340°0." Merely the difference between the two expansions will be absorbed in the feed pipe by defoπnation. In figure 5 are also the system movements plotted which are simulated by me~ns of the program package PIPESTRESS 111.

,

The caJculation fοϊ the critical cross sections of the T-pί,ece yie1<fιed in peak stresses of nearly 696 Nimm\_Accorcling the calculation results stresses ~η T-piece connection to the rnain pipe are highesϊwithin the whole feed water piping system .

. . .. . ,: . ' . .

Accorcling ASME-de.s1gή cιirve, figure ·6, ·3,500 loading cycles are allowable. tίll inci-· pient crack initiati~n occ~s . .

4. Chernical.Analvsis. Fractograplιical Examination and MeclΊanical-Technological Testings

The EDAX a~alysis was perfoπned at 40 and 20 kV1 figιires 7 and 8. Νο appreciable devia~όns in the chemical composition .. can be observed in compaήson with the specifications. · ·

One part Όf the cross section Q3 was cut out in the region shown in figure 9. Iri tl1e sketcl1 bottom left · there was the wall · thickness measured with 18.3 mm and the T-piece' wall thickness after the fracture with 13 πuη. Tlιe fracture area has a thick layer of corrosion; n9t removable even in an ultrasonic bath.

'.'

The few clean spots in the fracture a.re~ .$how ~.poradi.c. climpling, fiiures 1 Ο to 12 and also intergranular separation aήsing from creep daΏ?age.

Α part of the fracture in aoss section Q5 was sawed out, figιιre 13, and a fracto­graphic analysis was perfoπned . As shown in figures 14 and 15, there are once again signs of a creep damage ίη the frac tured surface.

: .. ,.J. • • .. Frorn one matι;:ό:alι-ήng ~ tensile test sp~cimen and Charpy V specimens have been manufacϊtured .. ~cc0rding· figu.re 16 . . The resu].t-of, t.h~ t~sti.ng, , figure i?, revealed low ductility···in· ffi~;ρi'ρe .'cross- clirection depending froxn the· position on circωnferehce. Also teήsile: tesHιιevealed increasv in yield $tI'ess to 702 N/mm2 • . ...•. ' - , .r ·

.. .:· "' · . ...

,.)

. . ..... ,.: ._ . .. ... . ....·.

. ... ,• • • ..~ • 1 • ••

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5. Seque:r:1ce of Events and Macroscoi1ic Findings ' (/

In figure 1, the ind.ividual fractur~ cross sections within. tbe pipe are identified by Ql to Q5. figure 18 sho\VS the pl::in view of the rnill level together with furnace area and the eight mills and the position of broken piping parts aiter explosion.

Since numψous intergranu1ar separations \νere found in the fracture areas of the cir­cnmferential seam sections and also in tb~ test Cbaipy V sρecimens , it can be as­sumed that a circumferential fractur·e starreιl in cross-secti.011 Q4 wlιich js accon:!inz p.ipe anaJysis r~sults together vιith Q3 cross section the most 1ύ.ghly stι·es sed.

The placcment of the broken ρipes sl-,ow ι:~at the pi·ρe oricnted to~;ιarcis the KOZ4.J'..ff . side i1ήρacted onto tl1e diagonal boilcr sιψport with the ρ:ipe bend and simultan·~~onsl:ι defornΊecl' . th~ welded-on ribs of :-ru.118. The piρe half pointing towards the PTOLEMAIS side first impacted on mil11. Most probably, section Α was caught οη ηιίll 1 and part Β was 11nrled into tlι.e dirι::.~ϊίon of the boiler wall. Part C ·was founcι betwcen mills 2 and 3. · · · ,, . . .

·-The view-- of two cross sections· idenrified as· Q3 (PTOLEMAIS side) and Q4 (ΚΟ7ΑΝΙ side) can be seen in fw_~e .19 and 20. Both fractures are predoωj.nantly

parallel to LΓΊe T-piece weld edge app1ox. 5 nun behind. t:.1"1e heat. affected zone. The fracture of cros.s. section Q2 c~n be se..en- in fig,ι.ιr:e 21. Once again, there are νi.sible sίgns of a ·fracru:re· wlJ.ictι 1s jnclined wit11 respect to the longitudlnal axis. ·

6. Creep Behaviour at 345.,C ' .. ·.) .

As fracrure-πiechaD.icaI analysis reveal, there could occur circιυnferential fracru.res •. ..;:.. ~, .. , ~· ·1.,.. '-. . • - •

under .Ψe;;,~S1;lrneq·Όpera~ng conditions όnly if there was a long. initial crack circum-- fereήtia1ly~icin~1#ea·- ί2/. Only this cόuld ·explain why no signs of lea.kage have been detected pnor tό.'the ~pture event: After recommendatiόns for Kardίa 2 non-desιruc­tive testing which were based on ~nalytical results for Κατdία 1 structures, circumfer­entially. oήented crack<; 200 πuη long and 4 mm deep at 12 o'clock position on botb sides of the T-piece were found. · ·

Since the event took place without· changes of external influences such as internal pressure or bending stress, only two νaήable factors can be established as the cause of the event. Ιη the first place there ίs the time-dependent reduction in ductility. Secondly, duήng operation the rnaterial separations could grow. Both effects, howeνer, are part of the creeρ mechanisrn, νιhich should not be pronounced at a temperature of 340 to 350°C, figιιre 22.

If the known time dependant mateήal values are extrapolated to lower temperahires, it is possible in this way to obtain the creep behaviour with higher stresses. At appωx. 350°C, a stress of nearly 450 Ν/πυn2 would lead to failure. after 100,000 hours of . loading, figure 23. The stress analysis yielded reference si:resses for the T-piece .cir­cunιferential welds of 696 N/mm2

• If one combines the;interna.1 pressure and bending stresses acting in the longitudinal direction of the pipes without stress concentration factors, it is possible that a stress in longitudina1 direction results in 51 Ο N/mm2.

This stress amount at the given temperature makes it possible, to assιime creep behav­iour within the ~ross sections in ψιestion.

· The intergranual separations within the material which were documented both metal­lographica11y and also fractographically underline the,-theoretically extrapolated values.

T11e fact that the measured Charpy V notch toughness in longitudinal direction more or · · less contained the initial values can be deήved from Mises' ellipse, figure 24. Defor­mation takes place predorninantly jn circumferential direction both in the tension and in compression phase of bendίng. Ίills is the reason why the greatest embήttlement was measured in circumferential direction. '

The effect of creep by temperatures und.er 400°C is not new. About this subject for low carbon steel.s reported Kei1 131 in 1972.

7. Remedial Measures

The damage analysis reveals that higher pή1nary and secondary stresses induced in the mateήal at ·31~0c caμsed creep deformations of. structure.

' .. .;:..~.,.-:~ ,, .

The creep de_forination is accompanied in the stressor areas with crack initiation and propagation beside strain induced mateήal embήttlement. Α part of the embήttlement can be based on temperaturcs ageing ·too. The stress dependent embήttlement on the pipe circurnference \Vas clearly docnmented.

For the future operation of the Kardίa 1 and 2 plant peήodical NDT-testing with dye penet:Γant or 'metal check method should be provided in high stressed sections as ~ shown in figure 25. Furtl1er should be thought about stress limitarion in the pipe areas operating iri a temperature region between 320 and 360°C. Piping with higher flexibil­ity cap be recommende<i as a onc of possible so1utions.

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8. Refereήces --. ;

111 · κ: Gorctis: PIPESTRESS, DST Computer SeIΎices S.A.- Geoeva, Swltzei·land

.· 121 Bruch d~r Spι":isewasserlei~ng in der Anlage Kardia 1,

· BTB-Janskγ Beήcht Nr. 377, Mai 1992

121 Erαst Keil at all:

...

Zeitabh?ngigkeit der Festigkeits- und Verf9πnbarkeitswerte νοη \x./arωfesten Sttίhlen im Τ eπιpt:.raturbereίch unter 400°C .. ι\rchiv fiir das Eisenhίitten•;.ιesen1 Oktober 1972, S~ite 757 bis 762

'.

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Figure 22: ιι

Figυre 23:

Figure 24:

Figure~

Extrapolation of creep mateήal data for 15 NiCuMoNb 5

Creep behaviour of 15 NiCuMoNb 5 at 350°C

DeforrD.ation of Q3 and Q4 cross section within the·Mises ellipse

Piping sections recoπunended for NDT

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1

1 1

. 1

1

1

1

separator---

QS

- . damaged pipes

0 circ. c~ack

@ circ. crack

Fi ~ure 1: Location of guillorine rupturcs' withίn the pipe

Ι ι

Chemical Con1position in Percenta2e

c 0,17 Si = 0,25 to 0,5 Μη = 0;8 to 1,2 Ρ = 0,035 s = 0,035 Ni = 1,0 to 1,3 Cu = 0,5 to 0,8 Μο = 0,25 to O,S Nb = 0,02

Mechanical Pro:ρerties

' a) rooΊn temperature

Rpo,2 = 430 N/mm2

Rm = 610 to 760 N/mm2

ISO· V (0°C) = 31 J

b) Τ = 340°C ·.)

R.P0.2 = 355N/mm2 -~

Fj~τre 2: Material r.pec·ificaτion of 15 NiCuMoNb 5 according to Mannesma11n-Werksιoffblan 414 Β (manufacιurer)

Γ

-+

ι fuill.Ll;_ ΚΛ!~J)JΛ 1 T-ι: i cce :ιcι:ordi11g ιο rnnno f<1ι: tι1rcr

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~--~~~ ~14_0_00~~---1

(T-piece

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°' Ν ,

5 Sm

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χ

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Figure 4: Sketch of furnace moνemerιts

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101 ~-~~~~~~~~~~~~, ~~~~20~MnMoNi 55

010 small Ο aίr 1

' specimP;n Ο water 5 ------ -- --lf----r-- -----ι o.2ppm 02

., / ASflιE - fεilure curνe pipe with . owater circ. we!d appm 0

2

----.~--- ---

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5 ι...., 7 p1ate -... not smoott1e 1 -ί:t"c<-f- ~ parent

.weldment smooth~d ~------·'·-·· ..._ • <.m;:ι~~~'--2 --· ----· - ~ - .. ·------ -, r · Υ ,

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ASME. design curve

10·: ο 2 2 ι_,__s . , , ι ο 3 ~ ι_ι__l_s _ __ι1 ο-ί,~-2ι___ι_..ι.__ι._s__,,. ~~10 s

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Load Cycles to Crack ΝΑ

PUBLIC POWEA COAPOAATION.KAADIA1 ΒΤΒ

HAXIHUH OISTORTION 319 . 090mm ΑΤ ΡΟΙΗΤ 470 DISTORTIOH FACTOR 0.077

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PIPESTRESS

JOB 200

LOAD CASE 14

PLOT IDEN 2

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ΟΑΤΕ 08/19/92 ΤΙΜΕ 09: 37: 47

SCALE 1: 191

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ffi ι­ω Σ

ΗJΤΕ- ί: : LAS EL • RLQS I T -~ιece s1de 1 :ι - ΝΑΥ-8: 1!:!7:34

50.000 LIVE SECONOS

ίJϊ :·; !ΞLΕ/·Ι ~ο-

ι, , ;; ELC!·1 •. }.; ·ί) . 967 ~.052 ··-sr κ 2.417 Θ. 1 12 C!; r: .1.533 0 . 238 /'!Ν ~: 1.1. 367 0.853 t-' i:. ι.: 1 5 78. 90~ 96 . 9.13 ΝΙ f: 9 . SS~ Θ . ί Ι S

cu κ 4.533 Θ .392 t·10 κ 1 .217 :J.795

------ΤΟϊΑL ϊ <J •(). Je0

:.JSEO PEIF: ΕΟΑΧ

:· :ΝΤΞ-ί.-ΖΑF:

LAeEι • RLQS ( J-pιece s ι ~e >

Ι ~-ΜΑ Υ-92 11 :17:Ξ4 5Θ .00Θ LIVE SECCNDS

!':IJ• 4Θ.Ό τrιτ .. ~. TKOFr=3Q. ZAF CJRF.i:ΞCT!ON

ELEM χ ~ Α F -

ALK 0.0006 1. ~63 e. Ι 34 1. ;302 SIK ·3 .1301 1 1 • ~'3S 0. 180 1 . ΘG3 ~F :1: ·ϊ>.0023 0.~~s 0.952 1. 40~ ι'1/\ι '\ 0 .. ~084 0 . 979 0. '380 1 . 002 FEr: 0 . 9498 1 .000 0.994 ι . 0e3 ΝΙΚ 0 . 0070 Ι .ΘΖΙ Θ.590 1 . 000 CUK 0.0038 0.976 0 . 652 1 . ~'ι)0

ΜΟΙ\ 0.Θ077 0 .9 10 0.9ϊ2 Ι . ·ί)Θ0

'.J Ι =~ ELEM CΡΞ ELiΞ i·1

AL 1\ 0.etiS? 0.4Ζ

SI κ 2.4 ' '3".' 0 . 56 C:l Υ. ~.s ::J ~. 1 a ΜΝ κ 1.ι.86n7 0.97 FE ~: 1579.9000 35.33 ΝΙ κ '3.5500 1 . 1 s cu :-< 4 . 5333 e u~ ΜΟ κ Ι. : 1 S7 0 .37

------TOTAL 100.~0

14-ΜΑΥ-9'2 . 11 19: 04 - ·SUPER RA TE= 0C~S TI M E-FS= 122 / 122 PRST=

QUANT 60LSEC 60LSEC

Β =RLQS(T- pi ece side) 1 ·j ΪΑf ~ Ι<Q<

---~-..;__,_,._ι _Cι-1<ιχn-----+--------+-

10 . 00 . ' 69Cl"'-IT 3 . 76Ι<ΕV Β EDA X

Figure 7: EDAX-analysis with 40 kV

:~τε:-·~ : ELEN ί< ί Α ,... ,.

ι . .:,sΕι " RLQS <T -p i ece i .~- :1ΑΊ-92 11: 41 ::;2 ALK 0.0004 1 .085 0. 267 1 . €{/1 .

5Ιι) . 0i30 LI VE SECONOS " SIK 0.0017 1. ι 16 0 .379 1 .001 NBL 0.0010 0.91~ 0 . ϊ3 Ξ 1 . 0ι()0

ί.JΤ ., ... · /10L 0.0043 0.901 ~. '789 : .000

ΕL!Ξ~1 CP S ELEi1 CRI\ 0.0026 0.998 0.986 1. 304 .~ι κ 0.900 Θ . 044 ΜΝΚ 0.0095 0.98 1 0.595 1 .00 1 sr !<; i --.-... ::i :i ~ 0. 169 FEK 0.9617 1 .000 0.999 t . 002 ΝΒ ι Ι . Θ S Ι 0 . 1~5 ΝΙΚ 0.0069 1 .018 0.8G2 1 . 000 MG ι 4 :! 46 0 . 43: CUI< 0.0050 Θ.97Θ Θ.891 1 .000 ι: R κ. 3.4.50 0. Ζ6ϊ ΝΝ κ 10.817 0 . 956 FE κ 972.533 56.825 Ν Ι κ 5. 1'!33 0 . 699 Ι.JΤ % cu κ ;f.

3.000 ·0 ·. 503 ELEM CPS ΞLΕΜ '

------ ι\l κ 0.9000 0. 15 TOTAL ΙΘΘ.000 51 κ 4.3333 0.40

·• Νθ ι 1 .0514· 0. 16 ιJSEO PEIF: ΕΟΑΧ ΗΟ ι 4. 1456 0.50

. CR κ 3.4500 0 .2 1

lNTE-7.-:ZAF: , ΜΝ κ 10.8167 0 .97

L.-19!ΞL .. Rι:.OS <T-piece ~i de ) F!Ξ κ 972. 633.4 96. 15

ί J - !1AY.-9'Z 11 : 42: 22 ΝΙ κ 5 . 1833 Θ.79

6'3 . 000 LIVE SECONOS· cu κ 3 : 0000 0.58 Υ,ΙJ :: 20 . Θ TILT= 0. n :OFF =30 . ------

ίΑF CORRECTION TOTAL

1.4-ΜΑΥ-92 .1.1:45: 33 SUPER ΤΙΙΥ.ΊΕ =

PRST-RA TE= .· ·0cPS FS- 3i?/ 31.7 Β =RLQS( T-piece s i de ) ..,

;1:.ιf.·-·,

2 .0Θ

94CNT 4.Θ0 6.00

2.1.SKEV

Fίgυre 8:. EDAX-analysis ·wiτh 20 kV

ΙΘΘ.00

QUANT 60LSEC 60LSEC

EDA X

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Figure 9: Saw-cut for REM-ana.lysis from Q3 region

ι:Ji ί Ι

...

Figμre 10: Fracωre derail wίιh small ductile chains

1 !

...

. ·

Figυre 11: Intergra.nual. f.rzmre parτs

..

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Fίgιιre 12: Incergτanua.1 rupr~·rrac~s

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ί , . ι: · 1 '· ί; ;, . ι 1 :1: .. '

- .~., .... ---· ' " . · -~

~""'_,,, ~.(~

\ Herc{usgeschnitt-ene Bϊuchflό:che

Figιιre 13: Βοιh sίdes of Q5 rupcure in parent mateήal

.. . ,

Fi gure 14: Lntergranual rυpωre traces within Q5 cross section (a)

...

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-~ ·i~

.._,:)'• .ιa• ι:

Fίgure 15: Intergranual nφιure ιraces wiιhin Q5 cross section (b)

45°

genormte ISO-Kerbschlagproben {Langsproben)

genorrnte ISO-Kerbschlagproben. (Ouerproben) Μiιιe der Kerbe auf 135° Umf angspdsition legen

genormte ISO-Kerbschlagproben (Qι.ιerproben) Mitte der Kerbe auf 45° Umf angsposition legen · ·

genormte I SO-Kerbschl~gpr,o~en (Querproben) Mitte de( Kerbe auf 230° Urήf angsposition legen . ,, , .,~.; , /.:., .

Γ-ίgιιre 16: Saιηρlc cι~ι -οιιι r!n11 on 11irc cί rc11n1rcrc11ι:c

360 ο

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ο ,, φ

(11

a. IJ)

g ο ι::

1,004

1,003~

1,002

1,00 1

ϊ

ο 30 60 90 120150180210240270300330360

Clrc. Positlonφ 1° .__ ____________________________ _,

Amblont Temperatιιre

. "") 40 ";) , Ι ~ Μίn. P.equirerr.enιs at Ambfont Tampιiranιre accoιdin1 ~ 36 t W&rf:~ tof tbtati 41 4 RS for 1 S NiCuMo/\b 5 . c: ~ 32 1 •

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_g 2β ι- ' > 24 >. Ω.. .... 20 JS

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10· ~ ... ,. -.... . ~ .

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ο 30 60 90 , 20 150 180 21 ο 240 270 300 330 360

Clrc. Posltlonφ / 0

'• . Fίgure 17: Charpy V ιoughncss at ambίent temperaτure, 80° and 150°C compared

witb NDT-fιndings

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Figure 19~ CίrcuΠ'ieren rial fracrure Q3 wirh fracαιre swface details at 6 ο' c!ock position (PTOLEMAIS side)

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Fi gι1re 20; Cίrcumferenti:ι.1 fr:ιcrure Q4 (Ί-picce side)

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fjgure 23: Stress- rime d.iagram for rnateήal 15 NiCuMoNb 5 under 350°C

(ambient temperature)

Q

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Fig;ure 24: Defoπnation of Q3 and Q4 wίthin the Mises ellipse

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