Investigations regarding the possibility of the use of test-specimens with reduced dimensions in the Niblink method of testing

(1)

LABORATORIUM VOOR

SCHEEPSCONSTRUCTIES

TECHNISCHE HOGESCHOOL

-

DELFT

RAPPORT Nr.

BETREFFENDE:

Investigations regarding the possibility of the use of test-specimens with reduced dimensions in the Niblink method of testing.

By dr.eng. S. Kubera.

(2)

July 1971.

INVESTIGATIONS REGARDING THE POSSIBILITY OF THE USE OF

TEST-SPECIMENS WITH REDUCED DIMENSIONS IN TI-lE NIBLINK METHOD OF TESTING.

by

S. Kubera. SHIP STRUCTURES LABORATORY,

Deift University of Technology, Mekeiweg 2, Deift,

The Netherlands.

Report no.

(3)

CONTENTS:

Int'roduction page 3.

Assumptions for the tests I, 3.

2.1. Material and dimensions

of the test-specimen t, 3.

2.2. Test conditions for series 1 and 2 2.3. Welded spècimens series with

reduced dimensions 't 5.

Test procedure 't 6.

3.1. Instrumentation of the drop-weight test t' 6.

3.2. Calibration tests 6.

Results of the calibration tests t' 7.

Results of the tests carried out

on the specimens series land 2 " 8.

Results of the tests carried out on the welded specimens

Conclusions from the tests

References Appendix 't _11.

t

11. I, 13. 'I _lLt.

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3

INVESTIGATIONS REGARDING THE POSSIBILITY OF THE USE OF

TEST-SPECIMENS WITH REDUCED DIMENSIONS IN THE NIBLINK METHOD OF TESTING.

By S. Kubera.

Introduction.

The NIBLINK method of testing /1/ is intended for testing low strength ferritic steels. The method is useful for estimation of critical regions

of weidments from the viewpoint of brittle fracture danger.

In the above method of testing, the dimensions of a test-piece were de-termined rather intuitively, including two important parameters, viz. the plate thickness and full cross-section of the weidment. Thé results of numerous of the tests carried out in different laboratories /2-7/,

indicated the specific features of the method as well as the limits of application. Some reservation still exists concerning the procedure of the testing because of the not very clear physical meaning of the crack opening displacement (COD) value measured by the tests, obtained on the test-piece as the result of repeated impact loading /8/.

The present paper deals with the research carried out in the Delft University of Technology, Ship Structures Laboratory, with the purpose

to prove the possibility of reduction of the specimen-dimensions in the NIBLINK test-procedure. Simultaneously the purpose of the investigations

was the collection of some special information enabling the-better under-standing and interpreting of the values measured by the tests. For these reasons the experiments were carried out applying more complicated

meth-ods of measurements than the usual NIBLINK testing-method /10/.

Assumptions for the tests.

2.1. Material and dimensións of the test-specimen.

All specimens were made from the same plate of a low carbon steel of a thickness t 30 mm.

The yield-point for the plate material was 25,4 kg/mm2 and the tensile

strength 40,1.i kg/mm2.

-For the bomparison tests, regarding the possibility of reduction of the test-specimen dimensions (fig. 1), two series of the test-specimens were used.

Series 1: with reduced height only, consisting of three _{groups of}

specimens:

Series 2: with reduced height and length:

-- N-B/2 h 65 mm, s 325 mm

- M/2

hz40mm,s228mm

- S/2 h ± 20 mm, s 152 mm.

Dr.Eng., Naval Architect.

Gdansk Technical University, Ship Research Institute, Gdansk, Poland.

- NIBLINK specimen (N-B/i) h

65mm, s

325 mm

- -intermediate specimen (M/1) h 40 mm, s 325 mm

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c: 4/2

7 i

FOR NIBLINK TEST SPECIMEN: h=65 ;

_{W=75 ;}

S=325 ;

L=360 ;

B= thickness of the. plate.

FIG:1 The dimensions of the test piece.

Notch dimensions see fig. 2

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116 2 Q2

(7)

All th specimens had the same notch dimensions as the' NIBLINK test piece (fig. 2)..

The breadth (B) of all of the specimens was constant and equal to the thickness of the plate (30 mm).

The dimensions of the S/2 specimen correspond nearly to the dimensions

of a standard test-piece for COD-testiog recommended by the CODA-panel

/9/. According to this proposal, the specimen should be of square cross-section (B W); the loading span (S) should be < the specimen-width (W)

and the notch-depth: a

2.2. Test conditions for series 1 and 2.

In the NIBLINIK-tes-t, the drop-hammer mass is related to the plate

thick-nss and corresponds to a weight in kg equal ò the plate thickness in mm.

Hence for N-B specimen used in the investigations the drop-hammer weight was fixed as. P 30 kg. For the specimens with reduced dimensions, the drop-weight was decreased relatiire to the crdss-section reduction.

It means that for all the specimens the following criterion was fulfilled:

energy of blow

-. equal for the same height of blow. notch cross-section

(8)

4 IR2

60 50-A40

30

o 10

X

(V) II

o-FOR ALL SPECIMEN:.

IMPACT ENERGY

- CONST

NOTCH CROSS-SECTION

tJmax

_nQ

FQR_SE

u,

II

Q-zo

HEIGHT

F SPE.IMEN (cm)

L = 3,25

L = 32,5

L=23,0

L=15,2

'FIG.3 Comparison of the

_mox

and

for the specimen:

series 1 and 2.,

4 '3

max max max

bending stress in notch cross-section,

_'rnax

is the deflection of the

spec-imen, calculated for static conditions). (Fig. 3).

Aöcording to the NIBLINK test procedure, the height of the first blow for ali specimens was the same (H 20 cm) and for the following blows

increased in steps of H 5 cm or H 10 cm.

_All the specimens in seriès i were tested at room temperature (T

20°C).

One part of the specimens in series 2 was tested at low temperatures

00, _100, _{-2O, -30°, -Lo°C).}

Specifications of the specimens of series 1 and series 2 are given in-table I (appendix 1).

2.3. Welded specimens series with reduced dimensions.

-The fundamental advantage of a specimen of the NIBLINK-type is that such a specimen with its dimensions -is sufficiently sensitive to give real information regarding the resistance of the tested material to fracture initiation. The NIBLINK-type specimen is especially useful for tests of all regions of weidment which can be critical, (these are HAZ, weld-metal

or parent plate material).

To check if this feature is not akianged by reduction of the specimen-'dimensions, a second stage of i s-t.g'at;ions was realized with use of

welded specimens (type W), with the dimensions like for the specimens of

type S.

All the.test-joints were weldedmanually. The weidments -were prepared by use of electrode-type CONARC 51 of higher strength (50-60 kg/mm2), or electrode-type RESISTEÑS of lower strength (L15-50 kg/mm2). For each

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elec-4/IZ. 2

STRAIN GAUGES

NOTATION:

ON SPECIMENS FOR CALIBRATION

75

37.5

I

.1

20

19 21

17 i6 -- 8

Q Strain gauge type PL.3 in direction X

Strain gauge type PC.5 in direction X and Y or Z

FiG: 1.

Location of the strain gauges on the specimen for calibration test.

HHL

30 SIZE

SPEd

NB

MEN

S

W

75

30

L

360

180

M 61 16

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6

trode one welded plate was made at room temp,erature (T z +20°C), and

one at lower temperature (T z 0°C). The specimens _{were machined with}

a notch cross-section in the weld-axis _{or in the HAZ (lo mm from the} we Id-axis).

All the welded specimens were tested _{at the following temperatures:} +200, 00, _-2O _{and -L1.O°C.}

Specifications of the welded specimens _{are given in table II} (append-ix 1).

3. Test procedure.

3.1. _{Instrumentation of the drop-weight test.}

In a conventional NIBLINK test procedure one variable is determined,

namely the Crack Opening Displacement (COD), being _{the residual value} after a blow, measured in the rion of _{the notch. The COD-value is} measured by means of a special COD-dial gauge.

For the investigations being ;the subject of this _{report, special} in-strumentation was applied for measurement of the. impact force

trans-mitted to the test-specimen by a

blow

and for measurmen-t of the-dynamical COD-value which corresponds to this force. )

Bytests at low temperatures, the temperature _{of the specimen was}

checked by means of a thermocouple connected directly to the specimen.

3.2. Calibration tests.

In the first stage of the investigations it _{was of special interest} io recognize the dynamical behaviour of a test-specimen under an impact loading and also to confirm that there is an essential similarity be-tween phenomena occurring at tests on a normal specimen

imen with reduced dimensions.

For this purpose two specimens (N-B and S) were used with 21 strain gauges fixed at corresponding points on both of the specimens (fig.

L)

Se report no. 160.

(12)

spec--7

In corsequence of the above calibration, all the specimens of series 1

and 2 were tested applying one strain gauge in the region of the notch.

For determining the relation between the force, COD and deflection fbr

the specimen, two specimens (N-B and S) Were tested in static condi-tions.

14 _{Results of the calibration tests.}

From the calibration tests on th N-B and S specimens, useful information was obtained regarding the magnitude of the strains in the particular

points of the specimens, caused by the successive blows.

The diagrams of fig. 5 and fig. 6 show the distribution of the strains in the notchcross-sections for both kinds of the test-pieces. The dia-grams, basically, are similar but there is a distinct higher intensity

of the strain-increase for the smaller specimen (fig. 7).

This effect may be explained as the greater influence of the notch depth

in consequence of the reduction of the specimen-height. Confirming the

above conclusion may be the phenomenon of a distinct shift of the actual

neutral axis.for the smaller, specimen shown on diagram fig. 7.

The diagrams fig. 8 and fig. 9 show the changes in the magnitude of the

maximum strain ( ) in the particular points of the notch

cross-sec-max

f ion, respectively for' the N-B and S-specimen. This maximum value of ttain'is the sum of the elastic and the residual value:

C C + C

max E R

Both the values

E and CR were recorded during the tests. As is visible

on the diagrams fig. 10, 11 and 12, there is a fundamental difference in the development of these two values. It is worthy to notice the high de-gree of similarity in the form of he curves of CE and

R for both the specimens.

.Besides the strain measurements the magnitude of the. impact force (F') and the residual COD (the last with aid of the special COD-dial gauge) were also measured. On fig. 13 there is a dimensionless comparison of

,the residual strains (CR) indicated by th'e strain .gauge at the tip of

the notch (No. 1), and the CODR_vlue, for the consecutive blows. From

this it may be concluded that only in the .very early stage of the

pro-cess, there is a linear correlation between these two values.

The strain gauges located at some distance from the notch cross-section (in the regions where only elastic strains occur), indicated the analogy of the strain-magnitude in these points and of the magnitude of the

im-pact force for corresponding blows (fig. 14).

Tle impact force curve in the final stage of the process shows an abrupt

deflection for both the specimens. This is caused by the reduction of the stiífness of the specimen at the beginning of the fracture. It can be expected that by the first blows, when the elastic deflection of the specimen is predominant, the impact force will be linearly depending on the square root of the energy of the blow ( En). As is visible on the

diagram fig. 15 (giving the impact force as a function of En), the

values of the impact force indeed approach to the straight line for the

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-8-On the diagram fig. 16 the impact force (Fmax) related .to the height _of

the specimen for both specimens was expressed _{as function of CODR.}

From this diagrain may be noticed.the relative higher loading of _the

specimen S, what is in good agreement with the picture of the phenomena resulting from the strain distribution in the notch cross-section for

both the specimens (fig. 5 and 6).

5. Results of the tests carried out on the specimens series 1 and 2.

In the series 1 and 2 altogether '42 test-pieces were tested. (Fig. ₁₇ and 18).

Records were obtained of the dyiamical and residual COD-value (COD

max

and CODR respectively) as function of the time, the impact force (F), and the strains in the tip of the notch.

The diagrams (fig. 20 till 36 - appendix) show the results of the above

values measured for each of the test-pieces group with different

dimen-sions.

It is visible that for ths test-pieces series i (NB/i; M/l; S/i - fig. 21,

22, 23) the reduction of the specimen height involved _{a distinct increase}

of the COD-value and the strains in the notch tip (fig. _{29 and 30).}

As result of the higher degree of the deformations in _{the region of the} notch, the specimens type M/l and S/i fractured after _{a smaller number} of blows. Simultaneously for the specimen with reduced _{height, a}

reduc-tion of the impact force was noticeable (fig. 31, 3'+).

In consequence of the length-reduction, the test-pieces _{in. series 2} 04/2. and S/l,, fig. 24, 25), indicated a less severe increase of the

COD-and strain-values, COD-and also a corresponding increase _{of the impact force}

(fig. 35, 36). The results for the specimens series _{2 better approach to}

values for the N-B test pieces, but the analogy _{was still not}

satisfac-tory (fig. 19) because of the too high COD rate increase.

For all the g'oups, the specimens tested under the condition of height 6f the blow-increase H 5 cm indicated higher values of COD than

the specimens tested for H 10 cm, for equal height of blow.

By the tests at low temperatures, the results for the N-B test-pieces

were rather easier for interpretation, because of more blows to the

frac-ture, as compared to the S/2 specimens (fig. 23, 25, 28, 31). Generally speaking it seems that the siope of and the deviation from the straight part of the COD-curve are more valuable to make comparisOns than only the COD-value for the last blow. The scàtter in the magnitude of the COD for the lat blow is visible also on the diagrams regarding the dynamical

COD measurements (fig. 27), and in particular for the tests at low tern-peratures (f 1g. 26, 28).

(14)

-9-

FIG: 17

Speamens

of.

the

series

i

after

tests.

ti/a

la

Crarirvnc

M

the

serIes

2 after

tests.

r

(15)

1,0

-

0,8-F' E U, E

o

-'

0,40,2

-COD =

f( hS)

'Ra

s

-4

40 .5

I

- SPECIMEN HEIGHT

(mm)

M

N-B

(16)

6. _{Results of the tests carried out on the welded specimens.}

Altogether 32 of the welded test-specimens with the dimensions like for

the specimens group S/2 (fig. 37) were tested.

'1i

FlG37 The specimen for investiqetion of the COD-votue for the

weLd-metaL and for the HAZ.

The comparison of the results for the _{welded specimens (fig. 38 till '31)}

is

interesting

_{because it indicates clearly that the method of testing}

is reliable enough to assess properties of _{the.weldments. The results} of the tests allow to distinguish not only rather _{rough differences} be-tween weld-metal and HAZ, but also more refined differences _{as the} qual-ity of the weld-metal (better results for the CONARC 51 electrode),. property of HAZ (better for RESISTENS electrode) and the ì.nfluence of the

welding conditions (worse results for the specimens _{welded at low} temper-ature: T _{O C in comparison to the specimens welded} _{at T}

.+20°C).t

e

7. Conclusions from the tests.

The tests were carried out _{on the test-pieces of one kind of the steel and} of once the thickness of the plate. This gives _{some limitations for}

gener-alization of the results.

The specimens with reduced dimensions were rather less'favourable in com-parison with the NIBLINK test specimen, because of too high rate of increase of the COD-value for the consecutive blows,Thjs disadvantage, it seems, Is easy to remove by changing the depth and sharpness of the notch More

satisfying results can be obtained also by the reduction of the steps of

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12

-the increase of -the impact loading by test.

In any case the results from the welded specimens allow of the conclusion that the specimen with reduced dimensions (in such a way that height of

the specimen thickness of the plate; and span length of the specimen I-tx height) may find application and may replace the specimen of NIBLINK

type, provided that some additional tests will be carried out to define

more accurately the requirements for the specimens and to establish the

(18)

13

-References.

/1/ Van den Blink, W.P. and J.JW. Nibbering:

"Proposal for the testing of Weld Metal from the Viewpoint of Brittle Fracture Initiation".

Metal Construction, 1969.

/2/ Guerrera, V., U. Girardi and L. Savarese:

"Different Types of Niblink and Longitudinal Drop Weight Tests

on Submerged Arc Weld for Determination of Brittle Fracture

Initiation Temperature". I.I.W. Doc. 2912-124-69.

f3/ Müncner, L. and J. Vrbensky:

"Brittle Fracture Initiation of Weld Metal Using Niblink Testing Method".

I.I.W. Doc. II-C-2912-70.

¡'4/ Ingham, T. and B. Watkins:

"Testing of Weidments Using Standard COD and Niblink Test Pieces". I.I.W. Doc. 2912-13c-69.

15/ Frederick, G. and R.V. Salkin.:

"Rf1exions sur Deux Essais COD Dynamiques".

Centre National de Recherches Mtallurgiques RA 77470.

/6/ Düren, C.:

"Some Aspects Regarding the Niblink-Test Procedure". I.I.W. Doc. 2912-113-69.

/7/ Düren, C.:

"Behaviour of Brittle Fracture of Welded Joints on Steel St. 52-3 in the Niblink Test, Impact Test and Pellini Test".

I.I.W. Doc. 2912-146-70..

/8/ Baker, R.G., M.G. Dawes, R.E. Dolby, G.R..Egan, J.D. Harrison

and G.G. Saunders:

"An Assessment of Brittle Fracture Tésting Techniques". I.I.W. Doc. 2912-137-69.

191 "The Use of Critical Crack Opening Displacement Techniques for the Selection of Fracture Resistant Materials".

First report of the CODA panel, 1969.

/10/ Kubera, S.:

"Measurements of Dynamic Crack Opening Displacements of Notched Steel Test Specimens under Impact Loading, According to the "Niblink" Test Pr9cedure".

S.S.L. report no. 160, July 1971.

/11/ Burdekin, F.M., R.E. Dolby and G.R. Egan: "Fracture Initiation in WeldedJoin-ts". Conference on Fracture, Brighton 1970.

/12/ Kanazawa, T., S. Machida., S. Momota and Y. Hagiwara:

"A Study of the C.O.D. C.çncept for Brittle Fracture Initiatiol-i". Conference on Fracture, righton 1970..

(19)

APPENDIX.

TABLE I. The Specimens Series i and 2.

15

-TABLE I. (Continuation).

The Specimens Series 1 and 2.

No. specimen no. h (cm) H max (cm) E max (kg/cm) En (kg/cm) S (cm) P (kg) A H (cm) T (°C) blow to fracture 3Lt 122/k 2 15,2 9,25 10 1- 20 5 60 555 1.850 35 122/5 2 15,2 9,25 10 + 20 6 70 650 2.500 36 122/6 2 15,2 9,25 10 + 20 6 70 650 2.500 37 122/7 2 15,2 .9,25 5 - 2 25 230 15 38 122/8 2 15,2 9,25 5 0 8 55 510 2.770 39 122/9 2 15,2 9,25 5 - 30 2 25 230 LQ _122/lo 2 15,2 9,25 5 - 20 35 325 1.020 fl 122/11 2 15,2 9,25 5 - 10 6 lî5 416 1.800 42 122/12 2 15,2 9,25 5 0 7 50 462 2.265

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16

-TABLE II. The Specimen Series

specimen

No. notch electr.

Tid

Ttest H blow to H

no. fracture max

oc oc cui cm 1 2111/1 W 60 20 20 5 36 200 2 2111/'2 W 60 20 0 5 26 145 3 2112 W 60 20 - 20 5 16 95 4 2113 w so 20 - 40 5 11 70 5 1111/1 HAZ 60 20 20 5 7 50 6 1111/2 HAZ 60 20 0 5 'f 35 7 .1112 HAZ 60 20 - 20 5 'f 35 8 1113 HAZ 60 20 - '40 5 1 20 .9 2121/1 W 60 0 20 5 36 200 10 2121/2 W 60 U 0 5 28 155 11 2122 w 60 O - 20 5 23 130 12 2123 W 60 0 - '40 5 7 50 13 1121/1 HAZ 60 0 20 5 5 40 l'-f 1121/2 HAZ 60 0 0 5 2 25 15 1122 HAZ 60 0 - 20 5 2 25 16 1123 HAZ 60 0 - '40 5 3 30 17 1211/1 W '-f0 20 20 5 17 100 18 1211/2 W 40 20 0 5 14 85 19 1212 W 40 20 - 20 5 9 60 20 1213 W 40 20 - '-f0 5 4 35 21 2211/1 HAZ 40 20 20 5 10 65 22 2211/2 HAZ 40 20 0 5 6 45 23 2212 HAZ 40 20 - 20 5 6 45 24 221 HAZ 40 20 - 40 5 1 20 25 1221/1 W 40 0 20 5 18 105 26 1221/2 W -40 0 0 5 l'-f 80 27 1222 W '40 0 - 20 5 6 45 28 1223 W 40 0 - 40 5 1 20 29 2221/1 HAZ '-f0 0 20 5 8 55 30 2221/2 HAZ

40

0 0 5 '-f 35 31 2222 HAZ '40 U - 20 5 3 30 32 2Q23 HAZ 40 0 - 40 5 1 20

(22)

I

l'i

u/

AWl_AA

':

IF

?AVr

EW4V

44'

I

47;

1

p

irF

'ft

A

!?.b!lIlIIIIIIlIIII

IpIll_

20cm

N°2 _N°4

- N°5

N°3 N°1

IN GAUGES

!INO5

1NO3

I

'I

110 cm

loo cm

90 cm

80 cm

70 cm

60 cm

50 cm

40 cm

N°1.

SCHEME OF IMPACT.

LOADING:

MAGNITUDE

MEASURED

FROM DIAGRAM

X

4 z

ZERO LINE

i

65

CMAX

SPECIMEN

HEIGHT

75 mm

I

w

>

I.-D.

wo

(n-J

o

LL

o

1Ii

C.D

l2Ocn

30cm

=20cm

FIG. 5.

Distribution

_{of the maximum bending strain}

_{( E max)}

in the

notch

cross-section

of

the

N-B specimen

for

consecutive

_{heights of}

_bLow.

NOTCH X

4 z

(4)

ZEO LINE

.4

w

o o

z

_z

LOCATION OF STRAIN GAUGES.

N°2

N°4

A

20 N°3

60 cm

50 cm

40 cm

30cm

H=20 cm

(n

:1

Q

II E C) .1 C%1 o

SPECIMEN HEIGHT: 30mm

w

I-D

wo

(n-J

zcn

o

OLi

o

H= 70cm

FIG. 6.

Distribution

of

the maximum bending

strain

_{( E maxi}

in the notch

cross-section

of

the

specimen

S

for

consecutive

heights of

blow.

(23)

X

E

w

50 cm

40 cm

30cm

H=2Ocm

o

z

J,

X

-I

D

w

_z

-j

4

C-)

I-w

'X

o.

w

I

u,

. o :

z

LOCATION OF

STRA?N

GAUGES

o

z

w

>

I-D

o

(J)

z

o

00

'X

o'-LjI

_(D

XI

4 UI

(t)

₁₂₀₀₀

L3

z.

4 8000

(J)

FIG. 8. Maximum strajis

in

particular

points

of

the

notch

cross

-section

of

N - B specimen , for

consecutive

blows.

Strain gauge :

N°

1, 2, 3, 6,5 and

12. FIG. 7.

Comparison of the maximum bending strains

in

the

notch

cross- section

of

the

N-B

and S specimens ,

for heights

of

blow

H=

20, 30, 60

and 50 cm.

NB

o

(24)

L

z

(n

A

24000

20000

16000

12000

8000

4000

8000

12000

16000

oo.

NB SPECIMEN

EE =f(N,E)

ER =f(N,E)

p"

N°2

ELASTIC

I

_¡

I RESIDUAL I

i

-ii

I

o

--_0

_-.-°'

_.N°3

110

HEIGHT

'

k

120

0F BLOW [cM]

FiG. 10.

Magnitude

of

the

eLastic

strain (E

_E

and

residual.

strain

(ER)

in

particular

points

of the notch

cross-section

of

N-B

specimen

for

consecutive

blows.

Strain

gauges:

N° 1,2, 3, 4.

(25)

ri

L

z

4

I-(J,

80

90

HEIGHT

loo

OF BLOW [cM].

FIG. 9.

Maximum strains in particular

points

of the

notch

cross-section

of

S specimen,

for

consecutive

(26)

12000-h

8000-4000

4000

8000

12000-. SPECIMEN CE

f( NE)

16000-

_ER

f( N,E)

ELASTIC

- - - RESIDUAL

o,'

o-:

Noi 100

OF BLOW fcm]

FIG. 11.

_{Magnitude of the}

elastic

strain

( E

E

and

residual

strain

_{( ER}

in

particular

points

of

the

notch

cross- section,

S specimen, for

consecutive

bLows.

Strain

gauges :

N° 1,2,3,4

24000-

2000016000

-12000

8000-4000

4000

8000-

12000-

16000-

.-

'-o

2O :

- -î: -4-_-°;

80 o

--..-u-.-

40

ELASTIX

- - - RESIDUAL

EE _ f(N,E

) R

f(N,E)

k:

I I .

o ZI

e'

O

I1

I,

for consecutive

bLows.

. 120

EIGI OF BLOW [cm]

,i!

I

/

60

,-

80 HEIGT )

I

'

/

(27)

L:J

w

D

_T

w

I

o

₄

OIL

ciq

O. C-)

D

T

w

t;

4

Ii.

w

i 00

80

60

40

20 10 20 30 40 50 . 60 70

80

90

100 110 120

HEIGHT OF

FIG. 13.

Comparison

of the relative

magnitude

of

residure

strain

N° i

in

vicinity

of

the notch )

and

relative

magnitude

sured

by means

of

COD - dial . gauge

)

for

consecutive

the

N-B

and S

_specimer.

BLOW [cM]

( strain

gauge

of

COD

(mea-blows

,

for

ri

X E -X

z

4 I

O

.0-O 10

20

30

40

50

60 70

80

90

100 110 120

130. 140

.

HEIGHT OFBLOW [cMJ

FIG. 14

Magnitude

of strain

indicated

by

the

strain

gauge

N° 6 and

10

for

consecutive

btows

in

relation

to the

maximum

impact

force

C F max )

for

specimen

N-B

and

S. 1400

1200

800

(28)

LJ

Lu

o

I-o

-X

A

60

50

40

30

20 lo

O

¡:i:;

_.(S//

_::

fi

IMPACT FORCE f('/)

I

/-I

I

FIG. l

_{Comparison of the impact force for consecutive blows for}

specimens N-B and S

, as

function of VEn

LJ

A

60

40 H 2

20

H = 50 H 40 H 30 40 H 30 H= 60

MAXIMUM IMPACT FORCE

SPECIMEN HEIGHT

su

I

'4

Fmax/ñ

,,N-B" Fmax/h

J1J

_C.O.D

FIG. 16

_{Maximum impact force Fmax. (in relation to specimen height) measured}

_{on the}

bridge part, as function of the C.O.D.-values measured after blow, by

means of

C.O.D.-ctiat gauge. Comparison for specimens N-B and S.

0,4 0,6

0,8

1,0 1,2 1,4 1,6

b

O 2 4 6 8 10 12

(29)

12

a

q

1.0 L) E

Q6

TaoL

S

C.O.D. MEASURED BY CQD -DIAL GAUGE

o I

20

30 40

BLOW HEIGHT(cm)

spedmen no

o

110/1

Ah:1O

A 114/2

Ah5

o

110/3

òh:5

110/4

AhlO

£

110/5

AhlO

110/5 A

h: 5.

1.4 Q8

Q'

0.2 1.0 ₅₀ ₆₀

₇₀

₈₀ ₉₀

_loo

110 120

BLOW HEIGHT (cm)

FIG. 20.

Residual

value of the

COD as

function

of

the

height

of

the

blow.

Results

for

the

(30)

1.4 0.8 0.6 0.4

02 -

0.06

ci

Q

o

-

0.04 0.02

Z

C.O.Dr = f( h)

AREN1 MATERIAL G22 KG/cmt

T=20°C

20 30

SPEC.

M,1

specimen dimensions:

325

360 CO.D. MEASURED BY CQD-DIAL GAUGE

Specimen no

A 111/i

ah1O

o 111/2

_'Ah10

O 111/3 _Ah=1O

£ 111/4

ôh=5

. 111/5

Ah5

111/6

Ah5

FIG. 21.

Residual

value,

of

the COD

as

function

of the

height

of

the blow.

Results

for

the

specimens

sertês 1,

group M/l, tested

at

temperature

T = + 2.0 °C.

40

50

60

70 90 90 100 110 120

(31)

o

112/5 A h=5 112/6 A h=5

-

0.02 50 I I 20 30 ¿0 50

60

70

80

90 100 110 120

BLOW HEIGHT (cm)

(32)

E

Q

°8

ZCOD.r = f(h)

SPEC. N-B12

specimen dimensions:

E

- a

0.06

o

CO.D. MEASURED BY C.O.D.-DIAL GAUGE

325 360 :

AH=5cm

0.02

/

specimen no

i"

. 120/i

T=-30C

120/2

T=+20C

.1

I

6120/3

T 0°C 20 3Ú ¿o

so

o 120//.

T-1O°C

BLOW HEIGHT (cm)

L 120/5

_T-20°C

o 120/6

T=-40°C

1.6 12 0.4 0.2 20 30

¡.0 ...50

60

70 80 90 100 110 120

BLOW HEIGHT (cm)

FIG. 23.

Residual p-value

of the COD as function' of the height

of the blow.

Results

for

the

specimens,

(33)

li.

î:

8

Q6 0.4 o I I C.O.D.r

f(h)

C.O.D. MEASURED BY C.OD.DIAL GAUGE

20 30 40

BLOW HEIGHT(crn)

specimen dimensions:

L

1H]

50

t I I

SPEC. M,2

PAR ENT MAT ERIAL

C= 22

KG/rn

_m

T =420°C

specimen no

12V

Ah10

A 121/2

oh=10

14/3

Ah10

£ 12x4

Ah5

D 121,

6h=5

o 12Y6

6h5

20

40

50

60

70

80

90 100 110 120 t

_{BWW HE[GHT(cm)}

FIG. 24

Residual value of the C.O.D. as function of the height

of the blows.

(34)

1.4 1.2 1.0 O.8

Ô

o

(j.

0.6

0.4 0.2

0.04 rEi

Ô

0.02

0.06 30 40

BLOW HEIGHT

50

CM]

I I

SPECIMEN S/2

. C.O.D.

.= f(H)

PARENT MATERIAL G= 22 kg/mm2

TESTS IN DIFFERENT TEMPERATURES

SPECIMEN DIMENSIONS:

L 152

-

180

30 C.O.D. MEASURED BY .C.O.D.

- DIAL GAUGE

20

30

40

50

60

70

80

90 100 110 120

BLOW HEIGHT [CMI

FIG. 25.

Residual

value

of

the COD as

f unctie

of the

height

of

the bLow

Results

for

the specimens

serres 2

,.

group Sl 2

tested

cit

temperature

T

+200, 00; - .200 and

L0°C..

o

A

specimen

N°

122/2

122/4

H=5

H=10

T= +20°C

T= +20 °C

122/5

¿ H=10

1= +20 °C

X _{122 / 6}

_{E H=10}

_{T=+20 C}

o

+

_{122 / 7}

_{t H=5}

₁₌

_{40 °C}

.

122 / 8

1H=5

1= 0 °C

D

122/9

H= 5

T= - 30 °C

122/10

H=5

1=-20 °C

*

122 /11

T= - 10 °C

(35)

VI 1200

ci

o

(S (mm)

14001.0

-1000 800 600 400 200 O 0.6 a3 SPECIMEN

_NBA

THE DYNAMIC

CRACK

OPENING DISPLACEMENT (C.D.max)

OE9

AT

DIFFERENT TEMPERATURES.

8

0.7

05 a'

02

0.1 C.O.I:lmox =f(h)

40°C

specimen no

o

a 110/5

T=+200C

o 120/3

1= 120/4 T=-10 D 120/5

T=-20C

A

_120/i

_T=-30

+

120/6 T=-4C?C I I I I I I I I I I 20 30 1.0 50 60 70 80 90 100 110 120

BLOW HEIGHT (cm)

FIG. 26

_{The dynamic crack opening disp1acement (C.O.D.max.)}

_{as function of the height of the blow.}

(36)

1400 -

THE VAWES FROM RECORDS BY TESTS:

1000

C

FIG. 27

flD.mof(h)

c.OD.- DEVICE

20 30 40

THE DYNAMIC CRACK OPENING DISPLACEMENT

_(caD.max)

AND RESIDUAL CRACK OPENING DISPLACEMENT

_(CO.Dr)

C.O.D.r = f(h)

SPEC. S,2

LOCATION OF THE C.OD.DEVICE

specimen no

o

_12/

oh= 5

0

_122,í

_ah40

o

122/5

ah=10

..

122/8

The dynamic crack opening displacement (c.o.D. max.)

_{and residual, crack opening displacement (C.O.D. r)}

_as

function of the height of the blow.

Results forthe series 2,

_{group Sf2, tested at temperature 1= 20°C.}

800

0.5.

(mm) 800 114

400 - 0.3

(12

200

-0.1 120 70 80 90 100 110

BLOW HEIGHT [CMJ

(37)

1400

1200

1000

800

600 b 400

o

C-)

200

0.7 0.6. 0.5 0.4 0.3

o

C-) 0.2 0.1

FIG. 28.

The

the

I I I I 20 30

40

50

60 SPECIMEN 9/2

C.O.D.max = f(H)

THE DYNAMIC CRACK OPENING DISPLACEMENT(C.O.D.max)

AT DIFFERENT TEMPERATURES.

specimen

N

70 80

90

100 110 120

BLOW HEIGHT

CMJ

dynamic crack opening

displacement (COD max)

as function

of

the

height

of

blow.

Results

for

series

2 ,

group SI 2 , tested

at

temperatures

T

+ 200;

0° ; -10 ° ; - 20 O ; -30 °;

and 1.0 OC.

D

o

122/5

122/12

T= +20 °C

T

0°C

122/11

1= 10 °C

£ 122/10

1= 20 °C

. 122/9

T= 30°C

I 122 / 7

1= 40°C

I F I

(38)

14000 8000 6000 4000 2000 400 200 0 20

SPECIMEN No

12(1/3 1=

o 124/4

T=-100C

+120/5

T='-200C AH5

.124/1

T=-30C

0120/6

1=-4CC T=+20°C

30.

¿0 50 60

BLOW HEIGHT (cm)

T=+20°C

SPEC. NB112

NOTCH STRAIN GAUGE INDICATiONS

LOCATiON ON THE SPECIMEN

NOTE: for each specimen there are

two dgroms;one (the highest value)

show the maximum strains by blow

second show the residual value

after blow.

SPECIMEN No

A 110/2

Ah=5

o 114/3

Ah=S

110/4 oh=10

o ii6,i

Ah=10

£ 110/6

Ah5

o T=+20C 0 20 30 40 50 70 80 90 100 110 120 BLOW HEIGHT (cm)

FIG. 29

Maximum (Emax) and residual (Er )

strains

in

tI'ie

region

of the

notch.

Results

for

the

(39)

80

90

100 110

BLOW HEIGHT ßJ

FiG..30. Strains in the region of the notch.

Results for the specimens series i, s/i type.

11.000

12000

10000

8000

r1

L

6000

4

c

I-(n

4000

2000

O

(40)

14000 12000

4000

2000

u. u A122/12

0122/li

o122 I 10 + 122/9 122/7 300 400 T = O °C

1=410°C

T = -20

T = - 30 T = - 40 C 100

200

NOTCH

STRAIN GAUGES INDICATIONS

STRAIN GAUGE LOCATION ON THE

SPECI ME N.

STRAIN

GAUGE

NOTCH

NOTE: Fof each specimen there are two

diagrams1 one (the highest value)

show the maximum, strains by blow

second show the residal

vaLue

after

blow.

SPECIMEN

N°.

0 122/2

AH5

* 122/4

H=10

A 122/5

H 10

T = + 20 °C

0 122/8

AH5

I I ¡ I

SPEC.

2 50 60 70 80

90

100 110 120

GLOW. HEIGHT (cm)

FIG. 31.

Maximum (E max)

and resuduat (E r) strair

_{¡n the}

_region

_of

_the

_{notch. Results}

_{for the}

_specimens

series 2,

S/ 2

type-..

D

TEST

PIECE

ER = f(H)

i

f(H)

Emax

400 SPECIMEN N°;

20

30 40 50 10000 8000

6000

20

30

40

(41)

ri

LJ

9000

8000

7000

6000

5000

w

4000

C-)

o

u-i-

3000

o

2000

1000

IMPACT FORCE

= f(BLOW HEIGHT)

SPECIMEN N-81 i

T=20°C

o

A

I

FIG. 32

_{Impact force as function of the height of the}

_blow.

_{Results for the specimens series i}

_{, group}

N-8/1 (NIBLINK)

..tasted at temperature 1= +20 °C.

130

specimen

N°

z H

(cm)

110/2

5

110/3

5

110/4

10 110 5 10

1106

5 T I 20 30

40

50

60

70 80

90

100 110 120

(42)

9000

8000

7000

6000

5000

4000

3000

2000

1000

IMPACT FORCE = f(BLOW HEIGHT)

SPECIMEN N-B/ 2

20

30 40

50

60

70

80

90

100 110

BLOW HEIGHT

[CMII

FIG. 33.

Impact

force

as function

of

the

height

of the blow.

Results

for

the, specimens

series 2,

group

N-B /2

-10°

120/5

5

-20°

120/6

5

-40°

(43)

9000

8000

7000

6000

5000

L

4000

C-,.

o

Li

i- 3000

L)

2000

1000

I

o

-

IMPACT FORCE = f(BLOW HEIGHT)

SPECIMEN

M/l

_T=+20°C

I I

o

A

D

10

20

30

40

50

60

70 80 90 100

BLOW HEIGHT

[CM]

FIG. 34

_{Impact force as function of the height of the blow.}

_{Results for the specimens series 1, group M/l,}

tested at temperature. 1= +20°C.

specimen

N°

H

(cm)

111/1 10 111/2 10 111/3 10 111/4 5 111/5 5 111/6 5

110

120

(44)

9000

8000

7000

6000

5000

4000

w

C-)

3000

2000

1000

0 IMPACT FORCE = f (BLow HEIGHT)

SPECIMEN M/2

T=20°C

I I I

u

D

A

.

o

I I I

specimen

N°

H

(cm)

BLOW HEIGHT [cr

FIG. 35

Impact force as function of the height of the blow.

Results for the specimens series 2, group M/2,

tested at temperature 1= + 20°C.

(45)

9000

8000

7000

6000

151

5000

w

4000

o

u-3000

2000

1000

O

IMPACT FORCE

f (BLOW HEIGHT)

SPECIMEN S/2

.

o

A

u

D

X

*

+

specimen

N°

20°

122/9

5

30°

122/10 5

20°

122/11 5

10°

122/12 5

0°

10 .

20

30 40 - 50

60

70

80

90

100 110 120

BLOW HEIGHT [CMI

FIG. 36.

Impact

force

as

function

of the

height

of

the

blow.

Recuits

for

the

specimens

series 2 , group

S/2, tested

at

temperatures

T = + 20° 0°, -10°, -20°, -30° and

(46)

1.4 '1.2 1.0 0.8

r1

LJOE6

d

o

0.4 0.2 o

I

A u u

I

-

0.06

-

'0.04

L

o

-

0.02 O

SPEC. W/1

r

TP

C.OD.

= f(H)

NOTCH IN WELD AXIS, ELECTRODE MAT.

G=4045kg/cm1a

TESTS BY DIFFERENT TEMPERATURES,

H =5

20

30

40 A

50 SPECIMEN DIMENSIONS

(t30

o

*

A

.

20 30 40 50 60 70

80

90

100 110 120 130

BLOW HEIGHT [CM]

FIG. 38.

ResiduaL

value

of the COD as function of the height of blow.

Results

of the

tests

of

the welded

specimens, group WI).

specimen

N°

temperature by

weLd °C

test

1211/1

+20

1211/2

+20

0 1212

+20

20

1213

+20

40

1221/1 0

+20

1221/2 0 0 1222

0

20

1223 0

40

152 180

c.O.D. MEASURED BY

C.O.D.DIAL GAUGE

IL

(47)

Z

C..Oflr = f( h) SPEC. W12

Results of the tests of the welded

specimens, group W/2

(48)

o

L) 0,4

02 SPECIMEN W13

Q_0R

f (H)

NOTCH IN HAZSELECTROOE MAT. G:40-45

TESTS BY DIFFERENT TEMPERATURES.aHS

SPECIMEN DIMENSIONS

C.O.O. MEASURED BY C.O.D.- DIAL GAUGE

TEMPERATURE BY

SPEC.

WELD

TEST

N°. °C 2211/1

+20

221112

+20

0

2212

+20

-20

2213

+20

-40

2221/1

0 +20

2221/2

0 O

2222

0

-20

2223

0

-40

20 30 40 60 60 70

80

90 100 110 120

BLOW HEIGHT [CM]

FIG. ¿0.

Residual value

of the COD as

function

of the height

àt

blow.

Results

of the

tests

of

the welded

specimens

group

W/3.

(49)

1.0 E

u 12

d

Q

t-) 1.0 0.8 0.6

0f.

0.2 50 BLOW HEIGHT(cm) I i i i i

C.O.D.rf(h)

SPEC. W14

NOTCH IN HAZ,ELECTRODE MAT. C50+60 KG/m

TESTS BY DIFFERENT TEMPERATURES. AH=5

specimen dimensions:

C.OD. MEASURED BY COED-DIAL GAUGE

0

20 30 1.0 50 60 70 80

90

100 110

BLOW HEIGHT (cm)

FIG. 1.1.

Residual value

of

the

COD

as

function

of

the

height

of

the

blow.

ResuLts

of

the

tests

of

the

welded

specimens

group

W /4.

120

specimen

No

temperature

by

weld

test

°c

+ 1111/1

+20

A _1111/2

₊₂₀

₀ 1112

+20

-20

1113

+20

- 60

°

_1121/i 0

+20

o

_1121,2

₀

a

1122 0

-20

*

1123