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Computer assisted design and modelling tool for precision powder moulding
1996 WORLD
CONGRESS
ON
POW-
DER METALLURGY. The abstracts which follow are from papers which were presented at the Congress, which was held in Washington, D.C, USA, in June 1996.
Modelling COMPUTER
ASSISTED TOOL
DESIGN
FOR
MOULDING
(‘. lkllis
AND
rt (II. (CEA, CEREM
EMM,?XM,
a computer
assisted
tool was described
design
with
and
regard
to
in precision powder moulding. was said to contain modules to
design parts and tools to yield a net shape part from powder. Finite element modelling of HIP was data
included.
for Ti alloys
steel
The
and
tooling and
system
stainless
over
tcmperaturc
USE OF POWDERS DERIVED GRINDING SLURRIES
SIMULATION
France)
application The system
different thickness could he used to control shrinkage anisotropy. Experimental and predicted data for Cu in a cylinder were compared.
a
was
MATERIAL
PRECISION
POWDER
l’rr(‘AD.
compressibility process conditions were investigated, of bonding.
CONSTITUTIVE BEHAVIOUR OF METAL POWDER DURING HIP WITH A
MODELLING
modelling
was emphasized. A modified finite element algorithm was used in the example of a cylindrical container. It was suggested that a container with ends and side walls of
contains steel
wide
using
range
validated
of
C. Greindreau c’t al. (University .J. Fourier, Grenohlc. France). It was noted that FE modelling of HIP needs equations which describe powder deformat ion under various states of stress and that experiments to identify thesr arc delicate and often inaccurate. Low melting point materials may be used. Studies of deformation of Pb powder at 150 C under a range of conditions wcrc described. It was reported that a new t.riaxial press had been developed. New were prnposcd.
formulations
l’or a real THERMOMECHANICAL
Ti alloy.
CHARACTERIZATION NUMERICAL FLOW
of equations
MODELLING
AND
HEAT
OF FLUID
TRANSFER
IN
THIXOMOULDING A. Garcia-tlejan rt (11. (National council of (Canada, Canada). Thixomoulding stages are involved. are loaded
into
deformed
by
causes
a heated a
material
is injected porosity
of a part
VIBRATION
into
a heated
A model
Moscow,
a system
predicts
of balanced
programme to evaluate Abouaf-s model parameters for HII’ of gas atomized 316L powder was described. It was repnrtrd that major deformation occurs during raising of trmpcrature and pressure. Results for heating from 8001125 C were presented. Microstructure evolution, as a and pressure>, Thermomechanical presented.
OF WATER
with
SF. Clacys USA).
This
system
that or
defect.s
Fine
equations
in a vibratory
It was reported of
of
the model
significant
and
this
was
in practice.
lsostatic pressing
function of temperature was described. data for modelling was
OF HIGH
COMPRESSIBILITY
ATOMIZED
IRON
POWDERS
(f’yrnn
Carp,
Niagara
Falls,
The need for Fe powders with high compressibility was discussed with regard to advantages accruing from their use. Studies to determine t,he parameters leading to high comprcssihility were described. It was repnrtcd that, chemistry of the Fe and lubrication were dominant factors. EFFECTS OF THERMAL TREATMENT ON PROPERTIES OF DIFFUSION BONDED FERROUS POWDERS
MODEL ASPECTS OF SHRINKAGE ANISOTROPY UNDER ISOSTATIC PRESSING E. Olrvsky
et al.
San
California,
Diego, Shrinkage
of deviatoric were
stresses
discussed
containers
(I.niversity
are
of California,
L. Tremhlay, F. Chagnnn (Quebec I’owders Ltd, Montreal, Canada).
development
It was powders
USA).
anisot.ropy
M.M. Didu, S. Sever (I:nivcrsit,>J of Craiva, Romania). Studies of ferrous powders made from grinding wastes were described. It was reported that grinding media had been reduced from 10% to less than l’:,. Applications were idcnt,ifird. AN INTELLIGENT PROCESSING APPROACH TO SPRAY DRYING SILICON NITRIDE
OF
V.K. l’ujari KI rz.l. (Norton Advanqrd Crramics, Worcester, Massachusetts. LISA) A two-stage, atomization and dr?/ing, spray drying process, instrumented and controlled for production of Si&, was described. The process was modrlled mathematically to study effects of variations in process conditions. Sensors data and with
Green strength and defects CRACKS
IN GREEN
D.C. Zenger, II. Cai Institute, I;SA). Cracks discussed cracking,
PM COMPACTS (Worcester
Polytechnic
in green PM components with regard to reasons location and avoidance.
were for A
database of defects. compiled from cast studies of parts, was described and t,hr findings discussed. Defect classification systems, characterization, mechanisms of crack formation and strategies for elimination were included. INFLUENCE OF POWDER CHARACTERISTICS ON SLIP
CRACK
Russia)
presented.
elimination
reduction confirmed
of
materials
was
Polytechnic
Powder production
OF
of particulate
to forces
(Worcester
ORIGINS
defects
compaction.
an example
(Academy
Products.
involved
and
of
PRODUCTS
E.K. Volshin-Chelpan
structural
mould.
A model
presented.
POROUS
Chemical
which semi-solid
is reported.
COMPACTION
FLAWLESS
relating
The
was described was
heavily
mechanism
melting.
Reduced
and
I1.C. Zenger, H. Cai lnstitutc, (ISA),
FROM
An experimental
described. Two of the fcedstock barrel
screw
partial
the process
was Chips
Research
OF STAINLESS
Effects of properties the degree
were used to gather experimental which were used wit.h the model control systems to make SirlN4 c’onsistfant specified properties.
OF HIP
CONSOLIDATION STEEL POWDER
was noted. on powder in particular
and
in the porous
and
the
importance
used
for
isostatic
volume
treatment
when
powdered control
pressing
Metal
shown that diffusion bonded Fe are generally made by heat of
Fe
powder
alloy elements. conditions to
mixed
with
The need to ensure high
S.
l’dkWIOt0
(Toyota Motor Carp, Japan) Origins of slip cracks, at stepped corners in compacts. were discussed. An investigation of mechanisms of crack formation was described. It was reported that reduced Fe powder is more likely to crack than atomized Fe powder. ENHANCED GREEN STRENGTH MATERIAL SYSTEM FOR FERROUS AND STAINLESS PM PROCESSING S.H. Luk, A.B. Davala (Hoeganaes (:orp, Kivrrton, New Jersey, ITSA). It was noted that low green strength in parts may cause subsequent process problems and that there is a nerd for higher
green
strengths.
It was reported
that
systems had been developed to make parts with green strength, enhanced by 50 to loo%, in materials.
ferrous
and
stainless
MPR October
1996
steel
43
CONGRESS
ON
POW-
DER METALLURGY. The abstracts which follow are from papers which were presented at the Congress, which was held in Washington, D.C, USA, in June 1996.
Modelling COMPUTER
ASSISTED TOOL
DESIGN
FOR
MOULDING
(‘. lkllis
AND
rt (II. (CEA, CEREM
EMM,?XM,
a computer
assisted
tool was described
design
with
and
regard
to
in precision powder moulding. was said to contain modules to
design parts and tools to yield a net shape part from powder. Finite element modelling of HIP was data
included.
for Ti alloys
steel
The
and
tooling and
system
stainless
over
tcmperaturc
USE OF POWDERS DERIVED GRINDING SLURRIES
SIMULATION
France)
application The system
different thickness could he used to control shrinkage anisotropy. Experimental and predicted data for Cu in a cylinder were compared.
a
was
MATERIAL
PRECISION
POWDER
l’rr(‘AD.
compressibility process conditions were investigated, of bonding.
CONSTITUTIVE BEHAVIOUR OF METAL POWDER DURING HIP WITH A
MODELLING
modelling
was emphasized. A modified finite element algorithm was used in the example of a cylindrical container. It was suggested that a container with ends and side walls of
contains steel
wide
using
range
validated
of
C. Greindreau c’t al. (University .J. Fourier, Grenohlc. France). It was noted that FE modelling of HIP needs equations which describe powder deformat ion under various states of stress and that experiments to identify thesr arc delicate and often inaccurate. Low melting point materials may be used. Studies of deformation of Pb powder at 150 C under a range of conditions wcrc described. It was reported that a new t.riaxial press had been developed. New were prnposcd.
formulations
l’or a real THERMOMECHANICAL
Ti alloy.
CHARACTERIZATION NUMERICAL FLOW
of equations
MODELLING
AND
HEAT
OF FLUID
TRANSFER
IN
THIXOMOULDING A. Garcia-tlejan rt (11. (National council of (Canada, Canada). Thixomoulding stages are involved. are loaded
into
deformed
by
causes
a heated a
material
is injected porosity
of a part
VIBRATION
into
a heated
A model
Moscow,
a system
predicts
of balanced
programme to evaluate Abouaf-s model parameters for HII’ of gas atomized 316L powder was described. It was repnrtrd that major deformation occurs during raising of trmpcrature and pressure. Results for heating from 8001125 C were presented. Microstructure evolution, as a and pressure>, Thermomechanical presented.
OF WATER
with
SF. Clacys USA).
This
system
that or
defect.s
Fine
equations
in a vibratory
It was reported of
of
the model
significant
and
this
was
in practice.
lsostatic pressing
function of temperature was described. data for modelling was
OF HIGH
COMPRESSIBILITY
ATOMIZED
IRON
POWDERS
(f’yrnn
Carp,
Niagara
Falls,
The need for Fe powders with high compressibility was discussed with regard to advantages accruing from their use. Studies to determine t,he parameters leading to high comprcssihility were described. It was repnrtcd that, chemistry of the Fe and lubrication were dominant factors. EFFECTS OF THERMAL TREATMENT ON PROPERTIES OF DIFFUSION BONDED FERROUS POWDERS
MODEL ASPECTS OF SHRINKAGE ANISOTROPY UNDER ISOSTATIC PRESSING E. Olrvsky
et al.
San
California,
Diego, Shrinkage
of deviatoric were
stresses
discussed
containers
(I.niversity
are
of California,
L. Tremhlay, F. Chagnnn (Quebec I’owders Ltd, Montreal, Canada).
development
It was powders
USA).
anisot.ropy
M.M. Didu, S. Sever (I:nivcrsit,>J of Craiva, Romania). Studies of ferrous powders made from grinding wastes were described. It was reported that grinding media had been reduced from 10% to less than l’:,. Applications were idcnt,ifird. AN INTELLIGENT PROCESSING APPROACH TO SPRAY DRYING SILICON NITRIDE
OF
V.K. l’ujari KI rz.l. (Norton Advanqrd Crramics, Worcester, Massachusetts. LISA) A two-stage, atomization and dr?/ing, spray drying process, instrumented and controlled for production of Si&, was described. The process was modrlled mathematically to study effects of variations in process conditions. Sensors data and with
Green strength and defects CRACKS
IN GREEN
D.C. Zenger, II. Cai Institute, I;SA). Cracks discussed cracking,
PM COMPACTS (Worcester
Polytechnic
in green PM components with regard to reasons location and avoidance.
were for A
database of defects. compiled from cast studies of parts, was described and t,hr findings discussed. Defect classification systems, characterization, mechanisms of crack formation and strategies for elimination were included. INFLUENCE OF POWDER CHARACTERISTICS ON SLIP
CRACK
Russia)
presented.
elimination
reduction confirmed
of
materials
was
Polytechnic
Powder production
OF
of particulate
to forces
(Worcester
ORIGINS
defects
compaction.
an example
(Academy
Products.
involved
and
of
PRODUCTS
E.K. Volshin-Chelpan
structural
mould.
A model
presented.
POROUS
Chemical
which semi-solid
is reported.
COMPACTION
FLAWLESS
relating
The
was described was
heavily
mechanism
melting.
Reduced
and
I1.C. Zenger, H. Cai lnstitutc, (ISA),
FROM
An experimental
described. Two of the fcedstock barrel
screw
partial
the process
was Chips
Research
OF STAINLESS
Effects of properties the degree
were used to gather experimental which were used wit.h the model control systems to make SirlN4 c’onsistfant specified properties.
OF HIP
CONSOLIDATION STEEL POWDER
was noted. on powder in particular
and
in the porous
and
the
importance
used
for
isostatic
volume
treatment
when
powdered control
pressing
Metal
shown that diffusion bonded Fe are generally made by heat of
Fe
powder
alloy elements. conditions to
mixed
with
The need to ensure high
S.
l’dkWIOt0
(Toyota Motor Carp, Japan) Origins of slip cracks, at stepped corners in compacts. were discussed. An investigation of mechanisms of crack formation was described. It was reported that reduced Fe powder is more likely to crack than atomized Fe powder. ENHANCED GREEN STRENGTH MATERIAL SYSTEM FOR FERROUS AND STAINLESS PM PROCESSING S.H. Luk, A.B. Davala (Hoeganaes (:orp, Kivrrton, New Jersey, ITSA). It was noted that low green strength in parts may cause subsequent process problems and that there is a nerd for higher
green
strengths.
It was reported
that
systems had been developed to make parts with green strength, enhanced by 50 to loo%, in materials.
ferrous
and
stainless
MPR October
1996
steel
43