Journal of Mechanics Engineering and Automation 6 (2016) 186-189 doi: 10.17265/2159-5275/2016.04.003

2D Finite Element Computer Analysis of Strength for

Brazed Joint of Cemented Carbide and Silver Brazing

Filler Metal

Meribe Richard Chukwuma1, Kazuya MORI1, Kento Takenouchi1, Yuki Fijishita2, Takeshi Eguchi2 and Kazufumi

Sakata2

1. Kumamoto University, Kurokami 2-39-1, Chuo, Kumamoto

2. Nakayama Seimitsu Co. Ltd.

Abstract: Brazing has a wide acceptance in industries and its simplicity in variety of application attracts more and more patronage. The strength of brazing joint determines the reliability of brazed engineering components. So the need to ascertain the reliability or to predict its failure (without some destructive testing) becomes high even with a computer aided analysis using the Finite Element Analysis. Here, we have employed the services of FEA software, Abaqus CAE, as a tool for the computer calculation to investigate a joint case of cemented carbide brazed with silver-based filler metal. In this paper, 2D analysis has been adopted because the thickness of the material (in 2D) does not influence the final calculation results. We have applied constant loading and constant boundary condition to explore data from the elastic and plastic strain analysis through which we were able to predict the maximum joint strength with respect to the joint thickness. The pattern of the meshing was also significant. And the result could be transferable to a real-life field situation. The final results showed that there is an optimum thickness of the filler metal with the maximum strength which matches that obtained from experiment.

Key words: Finite element analysis, brazing, cemented carbide alloy, silver brazing.

1. Introduction

In the field of processing using the die, the use of

materials with superior wear resistance is an easy

method of cutting cost. One of the particularly

superior materials is PCD (polycrystalline diamond)

with its high heat and wear resistance. PCD is sintered

on hard metal, cemented carbide as shown in Fig. 1

with the braze material in the gap. Fig. 2 shows an

example of a PCD punch. The strength of the PCD

tool depends on the strength of the brazing. The

authors obtained relationship of the bending strength

with the brazing thickness to study the brazing of the

super high alloy, as shown in Fig. 3. The difference

between cemented carbide ○ and ● is application of

Corresponding author: Meribe Richard Chukwuma, Ph.D.

student, research field: reliability and strength of materials.

pressure to brazed joint [1]. From the result of

experiment, it was understood that strength improves

when brazing thickness is more than 25 µm. In this

article, the analysis was based on the phenomenon that

joint strength decreases when brazing thickness

becomes thin using a finite-element analysis and

attention was paid to the extreme difference between

the hard metal and the brazing filler material and that

was considered.

2. Finite-Element Analysis

The authors performed a finite-element analysis in

reference to the specimen which was used (as in Fig. 4)

for experiment [2]. In experiment, specimens of

cantilever bending test of section dimensions, 4 mm ×

4 mm were used and, load was applied at the position

of 20 mm from the brazing joint. The mechanical

properties of the hard metal (cemented carbide) and

D DAVID PUBLISHING

Fig. 1 Manutools.

Fig. 2 Appli

braze mater

shown in T

specimen

distribution

the brazed

analysis, the

created the

part of the b

as it was as

force with th

The materia

method are

below (Tabl

the finite ele

Fig. 6 expre

and shade. T

too small to

brazed part.

is big. Becau

cemented ca

braze part

carbide is 9

yield stress (

biggest strai

material at

2D Finit

ufacturing me

ication of ceme

rial which w

Table 1. This

for the ex

is assumed

joint. Ther

e load orien

same effect

brazed joint

ssumed a mo

he boundary

als’ fixed v

also same as

le 1) same as

ement analys

esses the size

The deformati

o understand

It can be un

use of differe

arbide is 7

in a Youn

times bigger

(proof stress)

in and brazing

a stress of

te Element CoCa

ethod of polycr

ented carbide t

as used in th

s specimen i

xperiment,

constant at t

refore, in th

ntation was a

of tensile str

(area of stres

odel specimen

condition as

values in the

s shown in th

s in experime

sis is shown

e of the distor

ion of the cem

it from this

derstood that

ence of mecha

times bigger

g’s modulus

than the silv

). Fig. 7 show

g thickness o

400 MPa. T

omputer Anaarbide and Si

rystalline diam

to punch.

he experimen

s a bending

but the st

the upper par

he finite-elem

axial which

ress at the up

ss concentrat

n under a ten

shown in Fig

e finite elem

he table of v

ent. The resu

in Figs. 6 an

rtion by the l

mented carbid

figure; from

t the deforma

anical proper

r than the si

s and ceme

ver braze part

ws relations of

of the silver b

The deforma

lysis of Strenilver Brazing

mond

nt is

test

tress

rt of

ment

also

pper

tion)

nsile

g. 5.

ment

value

ult of

nd 7.

light

de is

m the

ation

rties,

ilver

nted

in a

f the

braze

ation

bec

µm

thic

of F

3. D

G

bec

Fig.thic

Fig.defomat

Fig.elem

ngth for BrazeFiller Metal

omes small

. This relate

ckness of mo

Fig. 3.

Discussions

Generally, str

omes thin [3

. 3 Bending ckness.

. 4 Cantileverormation at brterials).

. 5 Mesh pament analysis.

ed Joint of C

at brazing th

es that stren

re than 25 µm

s

rength is hig

3]. On the oth

strength of sil

r beam specimrazing material

attern and bo

emented

hickness of m

gth increased

m in result o

gher if brazi

her hand, in

lver brazing v

men (bold line bls in case of thi

oundary condi

187

more than 20

d at brazing

of experiment

ng thickness

brazing with

versus brazing

by the plastic ick brazing

ition of finite

7

0

g

t

s

h

g

e

188

Fig. 6 Strmagnitude of

Fig. 7 Strain

Table 1 Meand cemented

Young’s mod

Poisson’s rati

Tensile streng

0.2% proof st

Yield strength

silver brazin

decreases if

was conside

stress distrib

and stress re

It is belie

stress that

materials. Fi

that occurred

2D Finit

ain distributif the strain).

n versus brazin

echanical propd carbide.

dulus (Gpa)

io [-]

gth (Mpa)

tress (MPa)

h (MPa)

ng alloy and

f brazing thic

ered in our

bution when

edistribution.

ved fracture

was redistrib

ig. 8b shows

d when stress

te Element CoCa

ion (grey lev

ng joint thickn

perty of the b

Brazing fmetal

76

0.36

445

-

338

d cemented c

ckness is thin

investigation

it is a perfe

occurred at t

buted in the

stress distrib

s on the brazi

omputer Anaarbide and Si

vel represents

ness.

razing filler m

filler Cemented carbide

570

0.23

1270

2940

-

carbide, stren

n. This princ

n. Fig. 8a sh

ctly elastic b

the point of y

e whole bra

bution (bold l

ing material

lysis of Strenilver Brazing

the

metal

ngth

ciple

hows

body

yield

azing

line)

Fig.

reac

mat

T

stre

(thi

reac

thic

phe

mat

mat

4. C

In

phe

cert

soft

resu

(

muc

(2

µm

defo

(

ngth for BrazeFiller Metal

. 8 Stress dist

ched the dest

terial.

The stress d

ess distributio

in line in Fig.

ch the fract

ckness is t

enomenon oc

terials is rema

terials.

Conclusion

nvestigation

enomenon tha

tain point of

t silver brazi

ult, I got the f

1) The size o

ch smaller th

2) When silv

, in the fini

formation goe

3) From stres

ed Joint of C

(a) Thick braz

(b) Thin braz

tributions of b

truction poin

istribution (t

on in case o

. 8a). In other

ture point i

thinner. It

ccurs when

arkably lower

ns

was cond

at strength is

brazing thic

ing alloy and

following con

of the deform

an silver braz

ver brazing th

ite-element a

es minimum a

ss redistributi

emented

zing filler

zing filler

razing filler.

nt in case of

thin line) is

f thick brazi

r words, braz

in low load

is thought

the strength

r than the stre

ducted to

increased if h

ckness when

d cemented c

nclusions:

mation of the h

ze strain size;

hickness beco

analysis, the

and becomes

ion line at fu

thin brazing

lower than

ing materials

ing materials

d if brazing

t that this

h of brazing

ength of base

verify the

higher than a

brazing with

carbide. As a

hard metal is

;

omes than 20

size of the

constant;

ull-scale yield

g

n

s

s

g

s

g

e

e

a

h

a

s

0

e

d

2D Finite Element Computer Analysis of Strength for Brazed Joint of Cemented Carbide and Silver Brazing Filler Metal

189

of brazing, it can be explained why strength increases

if brazing thickness goes large until a particular point.

References

[1] Watanabe, K., Mori, K., Fujishita, Y., Kirihara, K., and Sakata, K. 2013. “High Reliability Brazing Technique on Brazed Joint of Cemented Carbide/Silver Solder.” Japan Society of Materials Science Reliability, Destruction Dynamics Combination Symposium Lecture Memoirs:

105-8. [2] Takenouchi, K., Mori, K., Richard, M., Fujishita, Y.,

Eguchi, T., and Sakata, K. 2015. “Improvement of Reliability of Brazing Joint on Cemented Carbide Alloy with Low Melting Point Silver Brazing Filler Metal.” Japanese Mechanics Kyushu Branch Office Nagasaki Lecture [memoirs].

[3] Association of Japan of welding. JWES joining, welding technology Q&A1000. http://www-it.jwes.or.jp/qa/details. jsp?pg_no=0080010080.