IS 3972-2-14: Methods of test for vitreous enamelware, Part 2: Test methods , Section 14 Resistance to adherence

2007·1.3 MB·English

by  Bureau of Indian Standards

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IS 3972-2-14 (2007): Methods of test for vitreous
enamelware, Part 2: Test methods , Section 14 Resistance to
adherence [CHD 9: Ceramicware]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
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“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
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“Knowledge is such a treasure which cannot be stolen”

IS 3972 (Part 2/See 14) :2007
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Indian Standard
METHODS OF TEST FOR VITREOUS
ENAMELWARE
PART 2 TEST METHODS
Section 14 Resistance to Adherence
(First Revision )

lCS 25.220.50; 77.080.01

0 BIS 2007

BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHAEUR SHAH ZAFAR MARG
NEW DELHI 110002
June 2007 Price Group 4
Ceramicware Sectional Committee, CHD 9
FOREWORD
This Indian Standard (Part 2/See 14) (First Revision) was adopted by the Bureau of Indian Standards, after the draft
finalized by the Ceramicware Sectional Committee had been approved by the Chemical Division Council.
This standard was first published in 1968. The Committee while reviewing IS 3972: 1968 decided to publish this
standard intwo parts. Part 1deals with production ofspecimens fortesting intwo sections, namely, Section 1Enamel led
sheet steel, and Section 2 Enamelled cast iron. Pall 2 deals with various test methods applicable to vitreous enamelled
sheet steel and vitreous enamelled cast iron. The Committee also decided that Part 2 shall have various sections and
each section will deal with a particular test method.
This standard prescribes the method for determination of adherence of vitreous enamelware. The other sections of
Part 2 are as follows:
Section 1 Resistance to citric acid atroom temperature andboiling temperature
Section2 Low and high voltage test fordetection and locating defects
Section 3 Resistance to boiling water andwater vapour
Section 4 Resistance to thermal shock
Section 5 Resistance to hot alkali (sodium hydroxide
Section 6 Reflectance and specular gloss
Section 7 Resistance to boiling hydrochloric acid
Section 8 Resistance to heat
Section 9 Resistance to dilute sulphuric acid at room temperature
.
Section 11 Resistance to abrasion
Section 12 Resistance to torsion
Section 13 Resistance to war page

Two methods have been described for evaluating the adherence of vitreous enamels and ceramic coatings to sheet
metal. Ofthese, the socalled ‘drop ball method’ shall beused as aroutine method and the other method using adherence
meter shall be the referee method.
The composition of the Committee responsible for formulation of this standard isgiven inAnnex A,
Forthe purpose of deciding whether aparticular requirement ofthis standard iscomplied with, the final value, observed
or calculated, expressing the result of atest or analysis, shall be rounded off in accordance with IS 2: 1960 ‘Rules for
rounding off numerical values (revised)’. The number of significant places retained inthe rounded off value should be
the same as that of the specified value inthis standard.
1S3972 (Part 2/See 14) :“2007
Indian Standard
METHODS OF TEST FOR VITREOUS
ENAMELWARE
PART 2 TEST METHODS
Section 14 Resistance to Adherence
(First Revision)
1 SCOPE 6 TEST METHOD
This standard (Part 2/ Sec 14) prescribes the method for Two methods have been described for evaluating the
determination of adherence of vitreous enamelware. adherence of vitreous enamels and ceramic coatings to
sheet metal. Of these, the so called ‘drop ball method’
2 REFERENCES specified in 6.1 shall be used as a routine method, the
method described in6.2, which uses adherence meter, shall
The followingstandardscontainprovisionswhichthrough
be the referee method.
reference inthis text, constitute provisions ofthis standard.
At the time of publication, the editions indicated were
6.1 Impact Resistance of Vitreous Enamelled Wares
valid. All standards are subject to revision and parties to
agreements based on this standard are encouraged to This method covers aprocedure for determining the impact
investigate the possibility of applying the most recent resistance of vitreous enamel led wares.
edition of the standards indicated below:
6.1.1 Apparatus
1SNo. 7We
6.1.1.1 Impact test machine of the falling-weight type as
~717 : 1979 Glossary of terms relating to vitreous
shown in Fig. 1.
enamelware and ceramic-metal systems
(Jvsl revision)
6.1.1.2 Cold-worked duralutnin ball — 20 mm in
3972 Methods of test for vitreous diameter, weighing 10.0 + 0.05 g.
enamelware:
6.1.2 TestSpecimens

(Part l/See 1): Part 1 Production of specimens for

Five identical utensils shall be tested.
1982 testing, Section 1Enamelled sheet steel
(first revision)
NOTE— ‘Identicalutensils’signifiesutensilofthesamesize,shape
andfinish.
(Part 1/See 2): Part 1 Production of specimens for
1982 testing, Section 2 Enamelled cast iron
6.1.3 Assembly of Apparatus and Specimen
@rst revision)
6.1.3.1 Levelling impact machine — Place the impact
3 TERMINOLOGY machine on afirm foundation, and, using the bubble level
For the purpose of this standard the definitions given in asaguide, level the machine bymeans ofthethree levelling
IS 2717 shall apply. screws. Tighten the nuts on the levelling against the
machine base to lock the levelling screw in position.
4 SAMPLING
6.1.3.2 Adjustment of guide tube — Rotate the 91 cm
Representative samples of vitreous enamelware shall be
guide tube (after loosening the clamps) until the two
drawn as specified in individual material specifications.
notches at the bottom of the tube are in a line, parallel to
the fi-ontof the machine. Raise or lower the guide-tube, if
5 TEST SPECIMENS
necessary, sothat two clamps fall between perforations in
The test specimens may be commercial items, parts thereof the tube; then tighten the clamps to hold the guide-tube in
or test pieces specially prepared in accordance with position. Raise the guide-tube assembly by lifting the
IS3972 (Part I/See 1)or IS3972 (Part l/See 2) dependi ng bottom clamp support, and swing to one side. This
upon the base metal used for enameling. operation places the guide-tube out of the way of the
1
lS3972(Part 2/See 14) :2007
operator when clamping test specimens into position and N[)ll — Care should betaken In tightening both sliding stops
also when changing specimens, without readjustment of andclmps, aserrorsmay beIntroduced If theutensil ISnotheld
firmly agatnstthebaseplate
[he guide-tube for every ware of any one set.
6.1.3.4 Locating fu[lirrg-weight contact point — Loosen
6.1.3.3 Cente~ing and ckmping ,specimw inpositior]— the three set screws that are located on the right side of
l’lace the inverted test specimen on the rotating disc and the guide-tube support rod base so that the guide-tube
centre approximately by means of the circles scribed support rod can be moved to and away from the front of
ihereon. Bring the four sliding stops in contact with the the machine. Swing the guide-tube back into itsnormal or
utensil and tighten, Then bring the four sliding clamps working position, using caution asthe Iowerclamp support
into position and set to hold the ware firmly against the settles down over its guide key, so that itisnot allowed to
rotating disc (seeNote). Move the disc until one of the ten rest upon the ware under test (see Note), Incase the guide-
evenly spaced grooves is directly in front of the guide- tube does touch the ware, it may be raised by ttirning the
tube support rod. elevation screw (see Fig. 1) until clearance isobtained. [t
SIJPPORT ROD EXTENSION
/-
/
d!.
)1
-GUIDFTUBE
STANDARD GUIDE
TUBE CLAMP J GUIDE TUBE CLAMP
EXTENSION ARM
/
SLIDING CLAMP
SUPPORT STOP
LOWERING AND
GUIDE TUBE DETAIL
RAISING FINE
ADJUSTMENT SETTER

ELEVATION
SCREW J
IDING STOP
EXTENSION ARM
---rSLIDING CLAMP
L

— ROTATING DISC
FIG.1 IMPACI TESTMACIIINE
2
,-,, .....—.. .——.————.c.. . .—
c ..—
-.
b
1S3972 (Part 2/See 14) :2007
may benecessary to move the guide-tube to or away from 6.1.3.5 Posi~ioning theja[ling weight — Place one of the
the support rod until the guide-tube is approximately two falling weight release pins through the set of
centered above the bottom radius of the utensil. This is perforations at a level of 125 mm below the specified
done by loosening the set screw holding the guide-tube- minimum height of impact, the utensil must pass, and drop
clamp extension arms, moving the guide-tube, checking the falling weight into the tube. Place the second release
to seethat the guide-tube isvertical, and tightening the set pin in the set of perforations directly above ‘the falling
screws. To permit both the backward or forward, and the weight now resting.
raising or lowering, tine adjustment movements of the
guide-tube assembly, loosenthe setscrewsinthesupport 6.1.4 Procedure
rod base and inthe sliding-clamp support stop. The correct
point of impact on wares which have abottom radius of 6.1.4.1 Begin the test by pulling the lower release pin,
less than 13 mm and a bottom diameter of not over which allows the falling weight to strike the bottom radius
178 mm maybe obtained by either one of the following ofthe ware atthe correct point of contact. Again drop the
two methods: falling weight into the guide-tube, and place the previously
pulled release pin inthe next set of perforations above the
a) Place the impact locator across the bottom of the
now resting falling weight. Continue this procedure until
ware, with the short arm resting upon the bottom
the first chip visible to the normal eye at the distance of
radius directly below the guide-tube. Lower the
44 mm occurs upon the enamelled surface of the utensil.
guide-tube by the fine adjustment setter until it
Atthis point, note the perforation directly below the release
nearly touches the bottom radius ofthe ware. Move
pin remaining inthe guide-tube, and record as the failure
the guide-tube to or away from the front of the
point, inmillimetres, for this particular point on the ware.
machine, asrequired, until the notches inthebottom
oftheguide-tubeareinlinewiththepointofcontact 6.1.4.2 Move the rotating disc until the next groove lies
between the bottom radius ofthe ware and the short in front of the guide-tube support rod, adjust the guide-
arm of the impact point locator. Tighten the set tube, ifnecessary, to provide the correct point of impact,
screws on the guide-tube support rod base to lock and again follow the above procedure, always starting the
the support rod in position; then raise the guide- test by releasing the falling weight from the set of
tube to apoint 3 mm above the point of impact on perforations at a level of 125 mm below the specified
the utensil, and lock in aposition by tightening the minimum height of impact the utensil shall pass. Repeat
set screw inthe sliding clamp support stop. Tighten this procedure until ten points on the bottom radius ofthe
the set screw inthe lower clamp support to prevent utensil have been tested, and have or have not failed at
a sideways motion of the guide-tube. some set of perforations within the length of the 91 mm
guide-tube.
b) Raise the guide-tube to a point 3 mm above the
point of impact on the utensil and tighten both the
6.1.4.3 One complete impact test consists in testing

set screw inthe sliding clamp support stop and the
each of five identical utensils as directed above for atotal
set screw in the lower clamp s upport. Place the
of 50 tested points.
impact weight on the bottom radius of the ware
directly below, and inside the bottom of the guide- 6.1.5 Calculations and Report
tube. Move the guide tube toor away from the front
Take the average of the ten tests on each utensil as the
ofthe machine, until the impact weight just remains
impact resistance of that particular utensil. Report the
in place. Then tighten the support rod base set
average offive identical utensil averages often points each
screws to lock the guide-tube in position. When
as the impact resistance value for the enamel.
round-shaped wires are tested, move the guide-tube
to, or away ffom, the front ofthe machine, and raise
6.2 Adherence Meter Method
or lower the guide-tube a small amount to obtain
This method isnot applicable tometals over 2mm orunder
the correct point of impact for each t~st point; this
0.4mm inthickness, nor to vitreous enamels on aluminium
adjustment is necessary, as the test specimen is
oraluminium alloys. Some anomalies have also been noted
centered only approximately on the rotating disk,
in certain processes in which the cover coat is applied
and some wares are not true in shape. When oval,
directly to sheet steel. Processes used inapplying the cover
square or rectangular wares are tested, move the
coat directly to sheet steel might require adifferent rating
ware itself for nearly every test point, and adjust
criterion from that used inevaluating conventional ground
the guide-tube for the correct point of impact at
coats on steel.
each test point.
6.2.1 Apparatus
NOTE — When returning theguide-tube toitsnormal orworking
position, donotforcethelower clamp supportdown uponthe guide Adherence meter isto be obtained from Porcelain Enamel
key, butletitsettle intoposition of itsown accord. Institute (PEI), USA, or from their authorized agents.
3
IS 3972 (Part 2/See 14) :2007
6.2.1.1 Die depth 6.2.4 Adherence Measurements
Dies ofdifferent depths are used for specimens ofdifferent
metal thickness. Details regarding these dies are shown in 6.2.4.1 Remove a portion of the enamel fkom acomer of
Table 1. the specimen to expose metal for attaching the spring clip
ground wire to the exposed metal.
6.2.1.2 Adherence meter
6.2.4.2 Allow 5min towarm upthe electronic components.
Itis essentially an electronic instrument equipped with
Raise the test head on the elevator post by means of the
169 needle-like probes assembled in hexagonal pattern
elevator knob. Place the specimen holder inposition. With
30.7 mm across the flats and 35.6 mm across the comers.
the concave side up, place the specimen on the specimen
Each probe is connected to an electric circuit, which may
holder with the deformation centered in the hole in the
be completed through the grounded base metal of the
spring supported plunger. Rotate the probe cluster to initial
specimen.
position by pushing the pivot knob to the left. Lower the
test head until the probes contact the specimen and the
6.2.2 TestSpecimens
plastic guard ring rests firmly on the specimen.
These shall be prepared as in 5.
6.2.4.3 Counter issetatthe zero position. Attach thespring
6.2.2.1 The test specimens consist of enamelled panels clip of ground wire to the exposed metal. Press the push-
not less than 10 cm in size. These specimens shall be button starting switch momentarily and observe the red
prepared by enameling seven different metal blanks and and green lights on the circuit box, The green light should
notby cutting tlom a single enamelled sheet. be lighted when the power is on, but the meter is not in
operation. The red light should be lighted momentarily
6.2,2,2 The test specimens shall have the type, thickness, after the momentary starting switch ispressed. When the
and number of coatings representing commercial practice measurement ininitial position has been completed, record
for the specific enamels involved. The thickness of the the counter reading and reset the counter to zero.
enamel or each specimen shall be measured atthe spot to
be deformed. 6.2.4.4 Raise the test head and rotate the probe cluster to
the next position (centre), Lower the head and repeat the
6.2.3 Deforming TestSpecimens procedure described in6.2.4.3. This isrepeated again with
the probe cluster in another fixed position, Thus three
6.2.3.1 The die shaIl be cleaned with asmall brush before readings on the same specimen are obtained.
each deforming operation.
6.2.5 Calculations for Single Determination
6.2.3.2 Each specimen shall be deformed at the centre.
6.2.5.1 One sample consists of seven specimens. Average

6.2.3.3 The specimen shall be placed o n the deforming the values obtained at the three angular positions of the

die mounted on the ram of the hydraulic jack and the probe cluster, to obtain the meter reading, ~, for each
motion of the jack will force the specimen against the individual specimen. Use the arithmetic mean, ~, of the
stationary steel ball centered above the die, thus deforming seven individual values, X, as the meter reading of the
the specimen. sample.
6,2.3.4 The specimen is deformed by full length strokes 6.2.5.2 Adherence index, A, iscalculated as follows (see
ofthe hydraulic jack at a rate that will consume 5 s from also Table 2):
the time deformation starts until 140 kg/cm2 pressure is
A . 169–X
obtained. This pressure is maintained for 5 s and then x 100
169
released.
6.2.5.3 Calculate the 95 percent confidence limit (statistical
6.2.3.5 For specimen having metal thickness between 2
error), e, forthe adherence index,A, as follows:
mm and 1.37 mm a circle should be marked with aglass
marking pencil around the end of the plastic shield while
100
the specimen is being held at 140 kg/cm2 pressure. This e= us 1= 0.59 aS
circle shall beused tocentre the specimen inthe adherence [–169
meter.
since for seven specimens, a = 1
e = 0.59 S
6.2.3.6 The deformed specimen should becleaned of loose
fragments by twice dropping the specimen, face down,
where S = standard deviation of the specimen meter
from a height of 15cm.

4
IS 3972 (Part 2/See 14) :2007
Table 1 Die Depths to be Used with Metal of Various Thicknesses
(Clause 6.2. 1.1)
sl NominalGauge of ThicknessofMetal DieDepth,A
No. Metal ~mum
Minimum
mm mm mm
(1) (2) (3) (4) (5)
i) 14 1,~018 2.0828 2,29
ii) 16 1.3716 1.7018 2.90
iii) 18 1.0668 1.3716 3.45
iv) 20 0.8382 1.0688 3.96
v) 22
vi) 24 0.4064 0.8382 4.47
vii) 26 }
viii) Research die — — 4.83
NOTE — Dies arestamped with thenominal gauge value for identification except thatonly No. ’24’ isstamped onthedie having adepth of
4.47 mm and‘~ isstamped ontheresearch die.
Table 2 Sample Calculation for Single Determination
(Clause 6.2.5.2)
SI Specimen Enamel Position Individual Mean ~ -23.0 (~- 23.0)’
No. No. Thickness ofProbe Readings x
mm Cluster
(1) (2) (3) (4) (5) (6) (7) (8)
I 30
i) I 0.206 2 33 33.7 10.7 I14.49
{ 3 38 }

I 46
ii) ~ 0.229 2 45 46.3 23.3 542.89
{ 3 48 }
1 31
Iii) 3 0.224 2 36 36.7 13,7 187.69
{ 3 43 1
1 24
iv) 4 0.249 2 26 28.0 5.0 25.00
{ 3 34 }
1 22
v) 5 0.241 2 26 28,7 5.7 32.49
{ 3 38 }
1 21
vi) 6 0.234 2 23 23.0 0.0 00.00
{ 3 25 }
1 45
vii) 7 0.218 2 48 47,3 24,3 590.49
{ 3 39
viii) Total 1.601 243.7 82.7 1493.05
ix) Mean 0.229 34.81 11.81

5
2—113 BIS/ND/07