IS 4857: Metallic powders,excluding powders for hardmetals - Determination of compactibility (compressibility) in uniaxial compression

2005·1.1 MB·English

by  Bureau of Indian Standards

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IS 4857 (2005): Metallic powders,excluding powders for
hardmetals - Determination of compactibility
(compressibility) in uniaxial compression [MTD 25: Powder
Metallurgical Materials and Products]
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IS 4857:2005
ISO 3927:2001

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( ah? )
Indian Standard
METALLIC POWDERS, EXCLUDING POWDERS
FOR HARDMETALS — DETERMINATION OF ‘-j
,
COMPRESSIBILITY IN UNIAXIAL COMPRESSION
( Fourth Revision)
ICS 77.160

@ BIS 2005
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DEL HI 110002
April 2005 Price Group 4
Powder Metallurgical Materials and Products Sectional Committee, MTD 25
NATIONAL FOREWORD
This Indian Standard ( Fourth Revision ) which is identical with ISO 3927:2001 ‘Metallic powders,
excluding powders for hardmetals — Determination of compressibility in uniaxial compression’ issued
by the International Organization for Standardization ( ISO ) was adopted by the Bureau of Indian
Standards on the recommendations ofthe Powder Metallurgical Materials and Products Sectional Committee
and approval of the Metallurgical Engineering Division Council.
This standard was first published in 1968 and revised in 1982. Itwas again revised in 1991 harmonizing
with ISO 3927: 1985. Since ISO 3927 has been revised again in 2001, therefore, need was felt to
revise IS 4857 also.
i
The text of the ISO Standard has been approved as suitable for publication as an Indian Standard
without deviations. Certain terminology and conventions are, however, not identical to those used in
Indian Standards. Attention is especially drawn to the following:
a) Wherever the words ‘International Standards’ appear referring to this standard, they should be
read as ‘Indian Standard’.
-{
.
b) Comma (, ) has been used as a decimal marker while in Indian Standards, the current practice
is to use a point ( .) as the decimal marker.
In reporting the results of a test or analysis made in accordance with this standard, if the final value,
observed or calculated is to be rounded off, it shall be done in accordance with IS 2:1960 ‘Rules for
rounding off numerical values ( revised)’.
IS 4857:2005
ISO 3927:2001
Indian Standard
METALLIC POWDERS, EXCLUDING POWDERS
FOR HARDMETALS — DETERMINATION OF
COMPRESSIBILITY IN UNIAXIAL COMPRESSION
( Fourth Revision)
1 Scope
This International Standard specifies methods fbr measuring the extent to which a metallic powder is compacted
when subjected touniaxial compressive loading ina confining die under specified conditions.
The method isnotapplicable to powders forhardmetals.
2 Symbols
Forthe purposes ofthis International Standard, the symbols given inTable 1apply.
Table 1— Symbols
Symbol Meaning Unit
PP Compressibility’ glen+
m Massofthecompact
v Volumeoftheccanpact m%
a Ifthecompressibiliitsymeasuredatonepressureonly,e.g.400Nlmrr+,thesymbobleOOmepSP(w).
,
3 Principle
Uniaxai compaction ofa powder inaconfining die bydouble action pressing. Samples ofthe powder may be pressed
either at a single specified pressure or at a series ofspecified pressures. After ejection from the die, the density of
the compacts isdetermined.

The density obtained inthe tbrmer case representa the compressibility ofthe powder at the specified pressure. The
densities obtained inthe latter case ca n be utilized tbrdrawing the compressibility curve ofthe powder, i.e. a plotof
the density as afunction ofthe compacting pressure.
4 Apparatus
4.1 Die, preferably of cemented cartide, or alternatively of tool steel, and two punches for producing either
cylindrical orrectangular compacts.
The cylindricaldieshould be capable ofmaking compacts ofdiameter 20 mmto26 mm and a heighttodiameter ratio
between 0,8 and 1.An example ofa design fir tooling isshown inFigure 1.
The rectangular die should be capabie of making compacts 30 mm x 12 mm and of thickness 5 mm to 7mm. An
example fora design fortooling isshown inFigure 2.
Mating parts shall be fitted and lapped.
4.2 Press, capable ofapplying tbrces uptoaproximateiy 500 kNwitha minimum accuracy of+ 1‘%0and adjustable
topermit an even increase ofthe time ata rate nothigher thaf?’50kN/s.
4.3 Balance, capable ofweighing at least 100 gtoan accuracy of+ 0,01 g.

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IS 4857:2005
ISO 3927:2001
Dimensionsinmillimetres
1
2
a) Die b) Punches
Key
1 Shrinkring
2 Cementedcarbide
3 Upperpunch,L = H – 10
4 Lowerpunch,L =H +35
Figure 1— Example oftooling to produce acylindrical test piece
4.4 Micrometer orother suitable measuring device formeasuring the dimensions ofthe compaota to an accuracy
of+ 0,01 mm.

5 Sampling

The quantity ofthe test sample shall be chosen to give the required number of test pieces (sea cfause 7) with the
dimensions specified in 4.1. If necessary, preliminary tests should be made in oder to establish the quantity of
powder needed forfulfillingthis requirement.
6 Procedure
6.1 Cleaning of the die and punches
Wipe the die cavity and the punches with softand clean paper towelling soeked with an appropriate sotvent such as
acetone. Allowthe solvent toevaporate.

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IS 4857:2005
ISO 3927:2001
Dimensionsinmillimetres
I
a) Die

Key
1 Cementedcsrbide
2 Shrinkring
3 Steel,HRC60to62
4 Upperpunch,L =25 c1
A
5 Lowerpunch,L =70
b) Punches
Figure 2— Example of tooling to produce arectangular test piece

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IS 4857:2005
ISO 3927:2001
6.2 Powder testing conditions
6.2.1 Powders which do notcontain a lubricant can be tested
a) ina dry die,
WARNING — Seizure and excessive die wear may occur, particularly at high compacting pressures
b) ina diewith lubricated walls (see 6.3.1), and
c) after admixing a lubricant (see 6.3.2) and ina dry die.
6.2.2 Powders which containa lubricant can be tested
a) ina dry die, and
b) after admixing additional lubricant (see 6.3.2) and ina dry die.
6.3 Lubrication
6.3.1 General
Use one ofthe twofollowing methods oflubrication,
6.3.2 Die wall lubrication
Apply to the die walls a mixture ora solution ofa lubricant ina volatile organic liquid, e.g., 100 g ofzinc stearste in
1000 cm3ofacetone. After any excess liquidhas drained away, allow the solution adhering tothe walls toevaporate
leaving a thinlayer oflubricant.
6.3.3 Lubrication of powder
Lubricate the powder to be tested by thoroughly mixing into.ita quantity (e.g. 0,5% to 1,5 ‘Y.) of a suitable solid

lubricant (e.g. zinc stearate orsynt hetic wax).

6.4 Compacting and ejection
Insert the lower punch into the die cavity. Position the die to the desired filling height by using supporting spacers
between the die and the footofthe lower punch. Pourthe sample intothe die cavity,taking the usual precautions to
ensure that the powder isuniformly distributed inthe die cavity. Positionthe upper punch and place the die withthe
punches between the platens of the press. Apply and release a preliminary force of approximately 20 kN. Remove
the spacers supporting the die. Ifthe die issupported bysprings, orinsome similar way, itisnotnecessary toapply
the preliminary fhrce.
Apply the finalforce ataconstant rate that shall notexceed 50 kN/s. Release the force as soon as the predetermined
pressure isreached.
Eject the compact from the die bymeans ofthe lower punch.
The procedure ofcompacting and ejection isexemplified inFigure 3.
After ejection and, ifnecessary, deburring, weigh the compact tothe nearest 0,01 g. Measure itsdimensions tothe
nearest 0,01 mm.

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IS 4857:2005
ISO 3927:2001
* i
a) Filling b) Pre-compacting
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1

c) Compacting d) Ejection
Figure 3— Procedure ofcompacting and ejection

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