IS 3972-2-13: Methods of test for vitreous enamelware, Part 2: Test methods , Section 13 Resistance to warpage

2007·1.3 MB·English

by  Bureau of Indian Standards

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IS 3972-2-13 (2007): Methods of test for vitreous
enamelware, Part 2: Test methods , Section 13 Resistance to
warpage [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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i!
IS 3972 (Part 2/See 13) :2007

8
METHODS OF TEST FOR VITREOUS
ENAMELWARE
PART 2 TEST METHODS
Section 13 Resistance to Warpage
First Revision)
(
ICS 25.220.50; 77.080.01

0 BIS 2007
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, /) BAHADUR SHAH ZAFAR MARC
NEW DELHI I10002

Jutle 2007 Price Group 4
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Ceramicware Sectional Committee, CHD 9
FOREWORD
This Indian Standard (Part 2/See 13) (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 published in 1968. The Committee while reviewing IS 3972:1968 decided to publish this
standard in two parts. Part 1deals with production of specimens for testing in two sections, namely, Section 1
Enamel led sheet steel, and Section 2 Enamel led cast iron. Part 2 deals with various test methods applicable to
vitreous enamel led sheet steel and vitreous enamel led 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 ofresistance ofvitreous enamelware to warpage. The other
sections of Part 2 are as follows:
Section 1 Resistance to citric acid atroom temperature andboiling temperature
Section 2 Low and high voltage test for detection and locating defects
Seclion 3 Resistance to boiling water andwater vapour
Suctloll 4 Resistance tothermal 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 14 Resistance to adherence
This standard covers aprocedure for determining the warpage of vitreous enamelled flatware prior to installation

as well as after installation.

Measurements prior to installation are made of the deviation of the free specimen from avertical reference plane
(free position).
[nthe other case measurements are made of the deviation and waviness from flatness remaining in the specimen
(a) after forcing the edges of the specimen into aplane (clamped position), and (b) after the specimen is actually
installed in walls, ceilings, etc (hstalled position).
The composition of the Committee responsible for formulation of this standard is given inAnnex A
For the purpose of deciding whether a particular requirement of this standard is complied with, the final value,
observed or calculated, expressing the result of a test 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 in this standard.
IS 3972 (Part 2/See 13) :2007
Indian Standard
METHODS OF TEST FOR VITREOUS
ENAMELWARE
PART 2 TEST METHODS
Section 13 Resistance to Warpage
First Revision)
(
1 SCOPE longer than the greatest width, and two of which shall
be longer than the greatest length of any specimen to
This standard (Part 2/See 13) prescribes the method
betested. All angles shall bepadded on one flange with
of test for determination of resistance of vitreous
a single thickness of cloth, attached with an adhesive,
enamelware to warpage.
to prevent scratching of the plate glass. Each upright
2 REFERENCE flange shall be equipped with two movable clamps, as
shown in Fig, 1.
The i’ollowing standard contains provisions which
through reference in this text, constitute provision of Any similar adjustable clamping device may be used
this standard. At the time of publication, the edition to replace the illustrated clamps. The angle irons and
inciicated was valid. All standards are subject torevision clamps shall be arranged onthe flat plate glass as shown
and parties to agreements based on this standard are in Fig. 2.
encouraged to investigate the possibility of applying
NOTE — TIIe term warpage is considered to inclade any
the most recent edition ofthe standard indicated below: deviotionfromflatnessofnormallyflat sort’aceof atiniskd
vitreoasenamelware.
[SNo, Title
4.4 T-Beam Gauge
2717:1979 Glossary ofterms relating tovitreous
enamelware and ceramic-metal The T-beam gauge as shown in Fig. 3 is used for
systems (jirst revision) measurements in clamped position. It consists
essentially of a dial indicator mounted on a carriage
3 TERMINOLOGY
designed to slide along the bottom flange of a T-beam
For the purpose of this standard the definitions given which is supported at the ends by adjustable legs. The
in 1S2717 shall apply. dial indicator shall have a range of 20 mm and an

accuracy of 0.1 mm. The T-beam shall be drilled at
4 APPARATUS intervals so that the distance between legs may be
4.1 Vertical Reference Plane shortened, if desired.
Tbe vertical reference plane shall consist of a vertical 5 TEST METHOD
or nearly vertical surface of dimensions larger than the
5.1 Measurement of Warpage in Free Position
specimens to be measured, and plane to within 1.0 mm. ,.. . . . . . .
Many specimens when warpeCt Into a twisted posltlon
A smooth plaster wall, a panel of plywood, or a sheet
of plate glass at least 6 mm thick may be used. An may easily be forced into the reverse direction of twist
and will retain either position, if not disturbed. Each
ordinary linear scale, graduated to 1.0mm shall be used
specimen should be measured in the position of
for measurements against the vertical reference plane.
maximum distortion.
4.2 Horizontal Reference Plane
5.1.1 The specimen is tested with long dimension
The horizontal reference plane shall consist of apiece upright and the face side against the reference plane.
of plate glass, 6 mm thick and flat within 0.1 mm, Place the two lower corners of the specimen against
resting on a table top or other surface which shall be thevertical reference plane, or ifwarpage prevents both
approximately tlat and level. from touching, place them as closely as possible to, or
equally distant from, the surface. Next, allow the top
4.3 Clamping Apparatus
of the specimen to move gently towards the surface
The clamping apparatus shall consist of four 62 mm x until some part otfhe specimen touches and brings the
5 mm angle irons, two of which shall beat least 300 mm specimen to rest. Support the specimen inthis position.
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IS 3972 (Part 2/See 13) :2007
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IS 3972 (Part 2/See 13) :2007
5.2 Measurement ofWarpage inTerxnsofDeviations
1millimetre
and Waviness Index in the Clamped Position
5.2.1 Fix specimen inside the frame of angle irons.
Mark with a pencil the four corners of the specimen,
12.7 mm from the boundaries of the flat portion, and
also four C1OSSmarks midway between the corners,
12.7 mm from the respective boundaries. Place the
specimen inside the frame of angle irons resting on the
glass plate, as illustrated in Fig. 1. Press down each
comer by hand, tighten the thumb screws until all four
comers are held snugly against the angle irons.
5.2.2 Adjustment of T-Beam
Place the T-beam gauge across the angle irons and
specimen with the legs resting on the plate glass as
shown inFig. 4.Adjust the single legatoneend ofthe
T-beamuntiltheT-beamisparallel withtheglass.This
N(HE — Did readingsare in hundredthof 1mmscalein condition will be indicated by identical readings of the
20mm dial gaLIge(eachsmallreading= 0.01mm).
dials when its stem isresting on asteel block or similar
FIG.3 T-BEAMGAUGE object placed on the glass alternately at the respective
ends of the T-beams.
if necessary, by pressure on the back of the specimen
5.2.3 Procedure
at t}le spot where contact with the wall brought it to
rest. With arule measure the distance ofthe test surface 5.2.3.1 Take dial readings of the relative height of the
atthe two upper corners of the specimen from the four corners of the specimens at the spots marked by
vertical reference surface to the nearest 1.6 mm. crosses. By means of shims (such aspaper tiling cards)
placed under the extended ends of the angle irons as
5.1.2 Calculation
shown in Fig. 4, raise all comers of the specimen not
Calculate the warpage ofthe specimen interms ofangle already in such position to the level of the highest
of twist per unit length as follows: corner. After this adjustment, the readings of the four
corners shall be within 0.1 mm.
1000 (Df - De)
T= ..(1)
LW 5.2.3.2 Push the dial along the T-beam, causing itsstem
where totraverse the specimen infour directions, namely, two
diagonals between the cross marks at opposite corners,

T =twist in percent per centimetre;
and two paths connecting the crosses at the midpoints

D~ = distance ofthe further comer ofthe two upper of opposite edges as shown in Fig. 2. Traverse No. 4
corners of the specimen from the vertical (see Fig. 2) maybe made by moving the whole T-beam
reference surface, in mm; while leaving the dial indicator inthe centre ofthe beam,
D, = distance ofthe closer comer ofthe two upper then avoiding the necessity of shortening the effective
corners of the specimen from the vertical length of the T-beam by moving the legs inward.
reference surface, in mm;
5.2.3.3 All of these traverses intersect at the centre of
L = length of specimen, in mm; and rectangular specimen. Record on the specimen the dial
W = width of specimen, in mm. readings atthe eight cross marks around the outer edge
of the specimen. In each traverse, note each point on
5.1.3 Sample Calculation
the specimen at which a reversal in the direction of
Assume DF = 94 mm rotation ofthe dial indicator occurs, and record at each
D, = 34 mm such point the corresponding dial reading. The position
L =1000mm and relative height of every crest and trough in each
traverse, will thus be recorded. The results indicate the
W = 600 mm
deviations and the waviness as given in 5.2.3.4
From formula(l), T= 1000(94-34) and 5.2.3.5.
10OOX600
5.2.3.4 Deviations
= 0.1 percentlcentimetre
= 10percent/metre. The positive and negative deviations are computed by
3
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IS 3972 (Part 2/See 13) :2007
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FIG,4 SPECIMENWHICUHASBEENMEASUREDBYCROSSEDCIRCLEFOR
WARPAGEINCLAMPEDPOSITION
subtracting the average of the four corner readings 5.2.4 Sample Calculation
(which must agree within 0.1 mm as specified above)
Assume the data as shown in Fig. 4.
from maximum and minimum readings respectively, on
the entire specimen. Deviations above the corners thus Deviation:
have a positive sign and those below the corners a
400–200= 4mm–2mm=+2mm
negative sign. Ifno reading exceeds the average of the
100–200= lmm–2mm=–lmm
corners readings, the deviation wiil be zero.
Wuviness:
5.2.3.5 Waviness
Traverse Differences
The results may fall into either of two categories as
1 378–200=3.78–2 = 1.78
follows:
378–200=3.78–2 = 1.78
a) Recording of twelve readings, representing 2 400 – 262= 4.00 – 2.62 = 1.38
two end readings and one intermediate reading
400 – 100= 4.00 – 1.00 = 3.00
for each traverse, does not show any evidence
238– 100=2.38– 1.00 = 1.38
of waviness, but indicates only that the
3 200– 176=2.00– 1.76 = 0.24
specimen is bulged.
350– 176=3.50– 1.76 = 1.74
b) If more than twelve dial readings are made,
350– 188=3.50– 1.88 = 1.62
calculate and record the differences between
200 – 188= 2.00 – 1.88 =0.12
all adjacent pairs of readings in each traverse
4 362 –275 = 3.62 – 2.75 = 0.87
having more than three dial readings. Discard
362 – 188= 3.62– 1.88 = 1.74
the two largest such differences found ineach
traverse, and forthe four traverses collectively, Remaining Differences:
separate allthe remaining differences into two
From traverse 2 ...... 1.38 WI
groups, namely, those less than 1.25 mm in
From traverse 3 ...... 0.24 W,
magnitude, and those ].25 mm or greater.
From traverse 3 ...... o.12wf
Designate the number of the former as W~
w, = 1, W,=2
(number of minor waves) and number of the
latter asWI(number ofmajor waves). Calculate w=5w, +wf
the index of waviness, W,as follows: =(5x1)+2
W=5W, +W W = 7 (waviness index)
f
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IS 3972 (Part 2/See 13) :2007
5.3 Nleasurcment of Warpage in Terms of Twist, Cl= centre reading of traverse 1,in mm; and
Deviation and kVaviness in Installed Position C, = centre reading of traverse 3, in mm.
[ktermine the \varpage of flat, vitreous enamel led items 5.3.2 Deviations
i installed in lval[s, ceilings or other locations where
For each traverse, separately calculate from the
suftlcient support can be provided around the specimen
I recorded dial readings the deviations above and below
for the legs of’the T-beam gauge, as follows:
the average end readings, that is the readings at the
Mark the centre of the specimen and make four
two ends of the traverse. Report the largest such
traverses as described in 5.2.3.2. In making each
deviations for the entire specimen.
trak’erse, adjust the T-beam until the two end
readings are equal to within 0.1 mm. On the 5.3.3 Waviness
diagonal traverses, record the dial readings at the
Calculate waviness as described in 5.2.3.5.
centre of the specimen in addition to the values
described in5.2.3.3. Identify these centre readings
5.3.3.1 Sample calculations
as reading C, and C,. Ifthe centre reading happens
a[so to represent ‘a crest or trough. record it AssUlne data as shown in Fig. 5.
separately without a subscript.
The essential difference between Fig. 5and Fig. 4 are:
(a) the respective centre readings for the two diagonal
traverses are recorded, although they do not represent
Calculate the amount of twist as follows: maxima and minima, and (b) the corner readings differ
by more than 0.125 mm. These differences are due to,
.(2) the fact that installed specimens must be measured as
found, without benefit of a flat reference plane.
where
L = 625 mm
T = twist. percentlcentimetre; W = 1300 mm
L = length of specimen, in mm;
From formula 2,
W = width of specimen, in mm;
E, = average readings at corners of traverse 2, T = ~v~~:~oo (6.62-12.70+12.00-7.00)
in mm;
= 0.0026 percentlcm
El = average readings at corners of traverse 1,
in mm; = 0.26 percent/m.

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FIG.5 lNSTALLED SPECIMEN WHICII IIAS BEEN MEASURED FOR WARPAGE INTERhm OF
TwIsr DEVIATION AND WAVINESS IN INs’rALLED POSITION
I
5