BRITISH STANDARD AUTOMOBILE SERIES BS AU 142 1968 Methods of test for Brake linings materials UDC 629 113 59 BS AU 142 1968 This British Standard, having been approved by the Automobile Industry Stand[.]
Trang 1Methods oftest for
U C 6 9.1 3-5
Trang 2This Bri shStan ard, ha ing
b en a pro ed b the
Automo ileIn ustry
Stan ardsCommi e an
en ored b the Chairman
oftheEng ine ring Divisional
Cou cil, was publishedu der
theauthoriy ofthe General
Cou cil of theInst uton on
3 J n ary1 6
© BSI0 -2 0
The folowing BSI reference
relates to the work on this
stan ard:
Commi e reference AUE/
-Automobi e Indus ry Stand ards Commit e of the BSI, is b sed upon d ta
she t SMMT C-3E:19 4 ( as rev ised in February19 7) of the Society of Motor
Manufac urer and Tra er Limited
I should be noted that the tes s in this s and ard are not intend ed to replace
the tes ing of brakes on a v ehicle or d y namometer, it being ac epted that a
ful as es ment of a l ning can be ma e only u der operating conditions The
tes s may , howev er, be used for checking the consis ency ofmanufac ure
Forthis purpose, the sup l er an the pur haser should reach ag re ment on
the selec ion of the tes s, the samplng procedures and the l mit to a ply to
theresult
The tes procedures des ribed are for the determination of cer ain phy sical an
chemical proper ies; they can be used for any lning material, an as a q ualty
cont ol check on that material
The proper ies should be identified with a p r icular brake l ning and not with
the brake or v ehicle on which this l ning is used
The tes proced ures are not intend ed to as is the d esig ner to fin suita le
materials for any p r icular a plcation since the proper ies do not neces ariy
bear any direc relationship to the perormance of the l ning in serv ice
A British Stand rd do s not purpor to include al the neces ary prov isions of
a cont ac User of British Stand ard s are responsible for their cor ec
a pl cation
Compl anc with a British Standard does not of itselfconfer imm unity
f om leg al o l g ations
Sum m ary ofpag es
This d ocument comprises a f ont cov er, an insid e font cov er, p g esi andi ,
p g es1 to15 and a b ck cov er
This s and rd has be n upd ated ( se copy rig ht d ate) and ma hav e had
amend ment incorporated This wi l be indicated in the amendment ta le on
the inside f ont cov er
Am endm ents is ued sinc publ cation
Trang 3Pag e
4 Asses ment offic ion and wear for qualty cont ol purposes 7
Fig ure 1 — Schematic diag ram of ty pical f ic ion materials tes machine 10
Fig ure 3 — Stand ard drum heating curv e, f ic ion materials tes machine 12
Fig ure 4 — Stand rd d rum co l ng curv e, f ic ion materials tes machine 13
Trang 51 Scope
This BritishStand ard g iv es method s for tes ing brake l ning fic ion materials to determine cer ain
phy sical and chemical proper ies The tes s g iv en include:
1) Density
2) Hard nes ( Brinel and Rockwel )
3) Cros breaking s reng th, for drum brake lnings
4) Acetone ext ac
5) Los of weig ht b ig nition
6) Asses ment of f ic ion an wear
2 Terms and definitions
For the purposes ofthis BritishStand rd the folowing definitions a ply :
2.1
brake lning
a piece of f ic ion material ma e to a sha e specified b a brake man fac urer
2.2
sam ple
a selec ion of brake lning s taken f om any b t h or del v ery of a p r icular material
2.3
spe imen
that p r of a sample brake lning on which tes s are perormed
3 Tests
3.1 General Specimens taken f om samples of brake lning s shal be subjec ed to the tes s des ribed in
this s and rd The siz of the sample and the n mber of specimens tes ed f om the sample shal be ag re d
betwe n the pur haser and the man fac urer W here alternativ e method s of tes ing are g iv en the
man fac urer shal , u les otherwise ag re d with the pur haser, selec the method he consider mos
suita le for the p r icular material
3.2 Density Two alternativ e methods are g iv en:
3.2.1Method1) The weig ht in g rammes of the specimen shal be d etermined within an ac uracy of±0.1 %
The mean d imensions of the specimen shal be determined within an ac uracy of±0.2 % and the v olume
computed in cubic centimet es The sha e of the specimen wi l d etermine how this is done; in the case of
an u dri led specimen which is in the form of an ar , the v olume Vis g iv en by :
The density of the specimen shal be computed as folows:
Density= g /cm
3
where W=weig ht of specimen in g rammes
where,
V=v olume in cm
3
A
1
=mean leng th of outer curv ed surace in centimet es
A
2
=mean leng th of in er curv ed sur ace in centimet es
b =mean width
t =mean thick es
The mean v alues in centimet es shal be determined b measurement
eq ualy sp ced along the specimen
V=
A
1 A
2 +
2
W
V
Trang 63.2.2 Method2 S spend the specimen f om a b lance p n ho k b means of a leng th of thin thread and
d etermine the weig ht of the specimen in air within an ac uracy of±0.1 %
Immer e the specimen in water at a temperature betwe n18°C and2 °C in such a wa that it is fe ly
suspended an do s not touch the sur ace of the water or the wal s of the water-container, and re-weig h
within an ac uracy of±0.1%
I the weig ht of the threa is smal ( les than0.0 %) comp red to the weig ht of the specimen, it ma be
ig nored
In weig hing the specimen in water, air bub les a hering to the specimen shal be remov ed Their remov al
can be faci itated b the presence of a t ace ( e.g one p r in100 0) of d eterg ent in the water, or b dip ing
the specimen momentari y into indus rial methy lated spirit, prov ided that it is k own that the material is
not afec ed b this t eatment I the lat er procedure is ad opted, care shal be taken that the minimum
amou t of spirit is t ans er ed to the water in which the specimen is weig hed
The specimen mus be weig hed as q uickly as pos ible afer immer ing in water
The density of the specimen shal be computed as fol ows:
3
3.3 Hardnes Two alternativ e methods are g iv en:
3.3.1Method1 B r inel ha r d ne s This tes which is b sed on the Brinel principles des ribed in BS2 0-1
1)
shal be car ied out with a hard nes tes ing machine fit ed with a b l indenter of5 or10mm diameter
The tes shal be a pled to the working sur ace of the specimen I neces ary , a smal amou t of material
ma be remov ed f om this surace b g rind ing in order to prov id e a smo th surace for the tes The ambient
temperature at the machine shal be betwe n18°C and2 °C
The specimen shal be firmly held in position with ad eq uate sup or f om below with the working surace
normal to the direc ion of a pl cation of the loa , and a piece of aluminium foi 0.0 0mm thick, located on
the sur ace of the specimen so that the result ma be observ ed on the foi
The ind enter shal be a pl ed with the specified loa for a period of15second s The loa and b l siz ,
selec ed f om one of the folowing s ales, shal be such that the impres ed diameter is betwe n one q uar e
and half of the b l d iameter:
W here two of these s ales wi g iv e result within the a ov e lmitation, the s ale selec ed shal be that
which g iv es the g reater diameter of impres ion
The impres ion c eated on the foi shal be ex mined an it mean diameter, taken as the av erag e leng th
of two diameter taken at rig ht ang les to each other, measured in mi imet es The specimen u d erneath
the foi shal also be ex mined ; if it is ev ident that the indenter has s ruck a hard inclusion or other p r icle
l a le to falsify the result, the rea ing shal be dis arded an another obtained
The result for each specimen shal be determined f om the arithmetic mean of the measurement f om at
leas thre indentations These ind entations shal be at leas 12mm fom any ed g e an u iformly sp ced
along the specimen
The hard nes shal then be determined as the quotient of the a pled loa div ided b spherical area of the
impres ion For the s ale used an the av erag e d iameter of impres ion obtained in mi lmet es the Brinel
hardnes n mber can be obtained fom Ta le 1, Ta le 2 or Ta le 3
a
=weig ht in air in g rammes
W
b
=weig ht in water in g rammes
1)
BS2 0, “Method for B r inel h r dne s tet,Part1, “Te tn of metals”
Scale Bal diam ete Lo d
A
B
C
mm
10
10
5
kg f a
3
10
7
a
1kg f=9.8 66 N
W
a
W
a – W
b
Trang 7Ta le 1 — Brinel hardnes num ber Scale A
Diameter of b l =1 mm; lo d=3 kg f
Diam ete
ofim pr s ion
mm
2.5
2.6
2.7
2.8
2.9
3.0
3.10
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4.0
4.10
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5.0
6.01
5.5
5.14
4.7
4.4
4.15
3.8
3.6
3.41
3.21
3.0
2.8
2.6
2.5
2.41
2.2
2.17
2.0
1.9
1.8
1.7
1.7
1.6
1.5
1.4
1.4
5.9
5.51
5.10
4.7
4.41
4.12
3.8
3.61
3.3
3.19
3.0
2.8
2.6
2.5
2.4
2.2
2.16
2.0
1.9
1.8
1.7
1.7
1.6
1.5
1.4
1.4
5.9
5.4
5.0
4.71
4.3
4.0
3.8
3.5
3.3
3.17
2.9
2.8
2.6
2.5
2.3
2.2
2.15
2.0
1.9
1.8
1.7
1.6
1.61
1.5
1.4
1.41
5.8
5.4
5.0
4.6
4.3
4.0
3.8
3.5
3.3
3.15
2.9
2.8
2.6
2.5
2.3
2.2
2.14
2.0
1.9
1.8
1.7
1.6
1.61
1.5
1.4
1.41
5.8
5.3
4.9
4.6
4.3
4.0
3.7
3.5
3.3
3.13
2.9
2.7
2.6
2.4
2.3
2.2
2.13
2.0
1.9
1.8
1.7
1.6
1.6
1.5
1.4
1.4
5.7
5.3
4.9
4.61
4.2
4.01
3.7
3.5
3.31
3.1
2.9
2.7
2.6
2.4
2.3
2.2
2.12
2.01
1.9
1.8
1.7
1.6
1.5
1.5
1.4
1.4
5.7
5.3
4.9
4.5
4.2
3.9
3.7
3.5
3.2
3.0
2.9
2.7
2.6
2.4
2.3
2.2
2.1
2.0
1.91
1.8
1.7
1.6
1.5
1.5
1.4
1.3
5.6
5.2
4.8
4.5
4.2
3.9
3.7
3.4
3.2
3.0
2.9
2.7
2.5
2.4
2.3
2.21
2.10
1.9
1.9
1.81
1.7
1.6
1.5
1.51
1.4
1.3
5.6
5.2
4.8
4.51
4.2
3.9
3.6
3.4
3.2
3.0
2.8
2.7
2.5
2.4
2.31
2.19
2.0
1.9
1.8
1.8
1.7
1.6
1.5
1.5
1.4
1.3
5.6
5.18
4.81
4.4
4.17
3.9
3.6
3.4
3.2
3.0
2.8
2.71
2.5
2.4
2.3
2.18
2.0
1.9
1.8
1.7
1.71
1.6
1.5
1.5
1.4
1.3
Trang 8Ta le 2 — Brinel hardnes num ber Scale B
Ta le 3 — Brinel hardnes num ber Scale C
Diameter of b l =1 mm;lo d=1 0kg f
Diam ete
ofim pr s ion
mm
2.5
2.6
2.7
2.8
2.9
3.0
3.10
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4.0
4.10
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5.0
2 0
18.5
17.1
15.9
14.8
13.8
12.9
12.1
1 4
10.7
10.1
9.5
8.9
8.4
8.0
7.6
7.2
6.8
6.5
6.2
5.9
5.6
5.4
5.19
4.0
4.7
19.9
18.4
17.0
15.8
14.7
13.7
12.8
12.0
1 3
10.6
10.0
9.4
8.9
8.4
8.0
7.5
7.2
6.8
6.5
6.21
5.9
5.6
5.4
5.16
4.9
4.7
19.7
18.2
16.9
15.7
14.6
13.6
12.8
12.0
1 2
10.6
9.9
9.3
8.8
8.3
7.9
7.5
7.17
6.8
6.4
6.18
5.9
5.6
5.3
5.14
4.9
4.71
19.6
18.1
16.8
15.6
14.5
13.5
12.7
1 9
1 2
10.5
9.8
9.3
8.8
8.3
7.91
7.51
7.13
6.7
6.4
6.15
5.8
5.6
5.3
5.12
4.9
4.6
19.4
17.9
16.6
15.5
14.4
13.5
12.6
1 8
1 1
10.4
9.8
9.2
8.7
8.3
7.8
7.4
7.10
6.7
6.4
6.12
5.8
5.5
5.3
5.10
4.8
4.6
19.3
17.8
16.5
15.4
14.3
13.4
12.5
1 7
1 0
10.4
9.7
9.2
8.7
8.2
7.8
7.4
7.0
6.71
6.3
6.0
5.81
5.5
5.3
5.0
4.8
4.6
19.1
17.7
16.4
15.2
14.2
13.3
12.4
1 7
1 0
10.3
9.7
9.18
8.6
8.21
7.7
7.3
7.0
6.6
6.3
6.0
5.7
5.5
5.2
5.0
4.8
4.6
19.0
17.5
16.3
15.1
14.1
13.2
12.3
1 6
10.9
10.2
9.6
9.12
8.6
8.17
7.7
7.3
6.9
6.6
6.3
6.0
5.7
5.5
5.2
5.0
4.81
4.61
18.8
17.4
16.2
15.0
14.0
13.1
12.3
1 5
10.8
10.2
9.61
9.0
8.5
8.13
7.71
7.3
6.9
6.6
6.3
6.01
5.7
5.4
5.2
5.01
4.7
4.5
18.7
17.3
16.0
14.9
13.9
13.0
12.2
1 4
10.8
10.1
9.5
9.0
8.5
8.0
7.6
7.2
6.9
6.5
6.2
5.9
5.71
5.4
5.21
4.9
4.7
4.5
Diameter of b l =5mm;lo d=7 kg f
Diam ete
ofim pr s ion
mm
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.10
2.2
2.3
2.4
2.5
6 3
5 5
4 7
41.5
3 3
3 1
2 5
2 5
2 9
2 7
18.7
17.0
15.6
14.3
6 3
5 7
4 1
4 9
3 9
31.7
2 2
2 2
2 6
2 4
18.5
16.9
15.4
14.1
6 2
5 8
4 4
4 4
3 4
31.3
2 8
2 9
2 4
2 2
18.4
16.7
15.3
14.0
6 1
5 0
4 7
3 8
3 0
3 9
2 5
2 6
2 2
2 0
18.2
16.6
15.2
13.9
61.1
5 2
4 1
3 3
3 5
3 6
2 2
2 4
21.9
19.8
18.0
16.4
15.0
13.8
6 1
51.4
4 4
3 8
3 1
3 2
2 9
2 1
21.7
19.7
17.9
16.3
14.9
13.7
5 2
5 7
4 8
3 3
3 7
2 8
2 6
2 9
21.5
19.5
17.7
16.1
14.8
13.5
5 2
4 9
4 2
3 8
3 3
2 5
2 3
2 6
21.3
19.3
17.5
16.0
14.6
13.4
5 3
4 2
4 6
3 3
3 9
2 2
2 0
2 4
21.1
19.1
17.4
15.8
14.5
13.3
5 4
4 5
4 0
3 8
3 5
2 8
2 7
2 1
2 9
18.9
17.2
15.7
14.4
13.2
Trang 93.3.2 Method2 R ockwel ha r d ne s This tes is b sed on the Rockwel principles d es ribed in BS8 1-1
2)
Rockwel hard nes is defined in terms of the depth of penet ation of a spherical indenter into the specimen
The b l shal be a pl ed to the working surace of the specimen I neces ary , a smal amou t of material
ma be remov ed f om the surace b g rind ing in order to prov id e a smo th sur ace for the tes , but the
specimen ma be flat or ra iused prov id ed that it is firmly held in position, with the working sur ace
normal to the direc ion of a plcation of the load , an with a eq uate sup or f om below The ambient
temperature at the machine shal be betwe n18°C and2 °C
The machine shal be ca a le of a ply ing loa s of10, 6 , 10 and15 kg f, of uti ising b l s
of3.17 mm,6.3 mm and12.7mm diameter an of ind icating the depth of penet ation of the ind enter in
u it of0.0 2mm A direc rea ing Rockwel hard nes tes ing machine, v erified in ac ord nce with
BS8 1-2
2)
is suita le
A prelminary load of10kg f shal be a pl ed and the depth measuring dev ice set to3 ( read ing on the
Rockwel B s ale for the direc rea ing machine) afer10second s An a ditional loa , in ac ord ance with
the s ale used , shal be a pl ed for a period of15seconds and then remov ed The Rockwel hardnes
n mber shal be read d irec ly f om the s ale of the direc rea ing machine5seconds afer the remov al of
the a ditional loa and with the prel minary load s i l a pled I a direc read ing machine is not av ai a le
the depth of penet ation, e, shal be taken5seconds afer the remov al of the major load an with the minor
loa s i l a pled
The Rockwel hardnes =( 13 –e) where e is the observ ed depth of penet ation in unit of0.0 2mm
The result for each specimen shal be taken as the arithmetic mean of the rea ing s f om at leas thre
ind entations The indentations shal be not les than12mm f om any edg e and u iformly sp ced along
thespecimen
The loa an indenter siz shal be chosen f om the fol owing s ales:
The choice of s ale shal d epend on the hard nes of the specimen and shal, where pos ible, be such that
the Rockwel hardnes n mber l es betwe n4 and9 u it Scale R would be used for sof materials
witha read ing les than4 u it an K for the hard es materials In cases where a material can be
tes edon two s ales within the l mitation the one selec ed shal be that g iv ing the smal er n merical v alue
of hardnes
I is es ential alway s to use the same s ale for any p r icular material
3.4 Cros breaking streng th (drum brake l ning s) This tes is to d etermine the ultimate s res , due to
bending , of a specimen with a rec ang ular c os sec ion which is reg ular throug hout the g aug e leng th The
wid th of the specimen shal not be les than10mm an shal be u iform ( ±0.2 mm) ov er the g aug e
leng th In the case of lning s exce d ing5 mm width, a specimen5 mm wide shal be cut f om the cent e
ofthe lning and the c os -breaking s reng th measured ac os the specimen The ambient temperature at
the machine shal be2 °C±5°C
The mean width and mean thick es ofthe specimen shal be d etermined b at leas thre measurement
ac os the lning
The specimen shal be placed , with the concav e sur ace upwards, sy mmet icaly ac os two p ral el
sup or s with3.2±0.12 mm ra ius sup or ing edg es The leng th of the sup or s shal be at leas the
wid th of the specimen
For specimens up to and including6.5mm thick es , the sup or s shal be set2 ±0.2 mm a ar For
specimens of greater thick es than this, the g aug e leng th shal be10 ±0.2 mm I a specimen tes ed on
the2 mm g aug e leng th fai s to break when the loa reaches2 5kg f a new specimen shal be taken and
Scale Bal diam ete Lo d
R
L
M
P
K
mm
12.7
6.3
6.3
6.3
3.17
kg f
6
6
10
15
15
Trang 10The loa shal be a pl ed sq uarely ac os the width of the specimen b means of a third block,
with3.17 ±0.12 mm ra ius bearing ed g e, which is p ralel to and mid-wa betwe n the sup or ing
blocks The load shal be inc eased s ea iy so that the specimen f ac ures in5 to15seconds The load in
kg f at fai ure shal be noted
Any tes s in which the f ac ure oc ur at riv et holes shal be dis eg arded
3.4.1 The c os breaking s reng th of the specimen shal be computed as folows:
Cros breaking s reng th= kg f/cm
2
Thre tes s per brake l ning are recommended , one tes at each end and one in the cent e Each result shal
be recorded
3.5 Acetone extract In the folowing method , the specimen is ext ac ed b acetone and the ext ac is
isolated and weig hed
A Soxhlet ext ac ion a p ratus comprising an ext ac or comply ing with BS2 71
3)
and a suita le flask an
condenser, al con ec ed with g rou d g las joint shal be used
The acetone used in the ext ac ion shal comply with BS5 9
4)
A specimen of fine p r icles of the fic ion material shal be prep red b dri lng with a10mm dri , using
cond itions which d o not produce v isible ov erheating The samples shal be d ri led perpendicular to the
working face, but not nearer than6mm f om the edg es The d epth ofdri ing shal be such as to obtain a
representativ e sample of the f ic ion material, u contaminated with any sep rate b cking lay er should
this be present, or with the material of the b ckplate in the case of dis brake p d s For the lat er, this wi
normaly mean that the d epth of d ri l holes wi l be a out6 % of the p d thick es
The weig ht of dri lng s req uired for the specimen is2±0.2g an suficient holes should be d ri led to g iv e
this weig ht I is not ad v isa le to dri a much larg er weig ht and to take a p r of it for the required
specimen The time betwe n d ri ing the specimen and ext ac ing shal not exce d4 hour
The specimen shal be weig hed to0.0 1g , and shal be wra ped securely in a fi ter p per The wra ped
specimen shal be placed in an ext ac ion thimble, ( prev iously fat ext ac ed)2 mm b 8 mm sing le
thick es and t ans er ed to the Soxhlet ext ac ion a p ratus Suficient acetone shal be a d ed to fi l the
ext ac ion u it plus a fur her2 ml Ext ac ion shal proce d for six hour , or a shor er period b
ag re ment betwe n man fac urer and pur haser The cy clng rate during ext ac ion shal be10
to2 cy cles per hour On completion of the ext ac ion period the flask shal be remov ed at a s ag e when the
ext ac ion u it is nearly fi led with acetone This should leav e a out15ml of acetone in the ext ac ion
flask The content of the flask shal be t ans er ed to a preweig hed v it e us si ica c ucible, the flask
washed out with a proximately5ml of acetone and the washing s t ans er ed to the same c ucible The
c ucible shal then be placed on a water b th and the acetone ev aporated S ita le precautions ag ains
ac idental ig nition of the acetone should be taken The c ucible shal final y be dried for ten minutes in an
ov en at8 to8 °C, and shal then be t ans er ed to a desic ator, al owed to co l and reweig hed
The per entag e acetone ext ac =
where,W=load at faiure in kg f
L=g aug e length inmm
B=mean width of specimen inmm
D=mean thick es of specimen inmm
3)
BS2 7 , “ Soxhlet extr actor s”
4)
BS5 9, “Ac tone”
where,W
1
=weig ht of specimen
W
2
=weig ht of c ucible empty
W
3
=weig ht of c ucible plus ext ac
15 WL
B D 2
10 (W
3 – W
2 )
W
1