Cost effective, high density P/M parts with existing equipment

By Dennis Hammond

Apex Advanced Technologies, LLC

Requirements to obtain high density

The level of lubricant used must be reduced, while not negatively impacting the part or processThe lubricant must be mobile, so that it migrates during pressingThe lubricant must be more effectiveThe lubricant must be effectively removed during the sintering process

Effect of lubricant on density FN 0205

Lube Wt. %

1.00% .75% .50% .35% .30%

Lube vol. %

6.99% 5.33% 3.63% 2.56% 2.20%

Pore Free Den.

7.21 7.33 7.46 7.55 7.58

98% pore Free Den.

7.07 7.18 7.31 7.40 7.43

• Solids as a general rule increase their melting point with increased pressure

• There are exceptions to the rule e.g. ice

• Clapeyron - Clausius formula predicts that when the density of a substance in its solid state is less than the density of the substance in its liquid state, then the melting point of that substance will decrease when pressure is increased

Physical State

• Rheology - Study of the deformation and flow of matter in terms of stress, strain and time

• Useful in modeling behavior of a substance in a process and process control

• Example - processing polymers, paints, coatings and adhesives

Rheology

• There are different types of rheometers for different applications

• We are using data from a capillary rheometer to model behavior from our lubricant

Rheology - cont.

Heaters

Capillary Rheometer

10

100

1000

10000

100000

10 100 1000 10000

Shear Rate (1/s)

Vis

cosi

ty (

Pa∙

s)

Dilatant

Newtonian

Pseudoplastic

Most polymeric materials are pseudoplastic (shear thinning)

Basic Curve Shapes

Rheology - cont.Shear

Rate

1/s

30C

86F

PSI

30C

86F

Pa S

38C

100F

PSI

38C

100F

Pa S

60C

140F

PSI

60C

140F

Pa S

1000 8531 726 3851 328 1170 100

2000 8364 355 3998 170 1338 57

5000 7732 132 4043 69 1602 27

Rheology - cont.Conclusion - hard solid with crystallinity that flowed from a solid to a liquid under pressureHigher temperature with pressure and shear reduced the viscosityP/M press has speed/shear, temperature due to particle to particle friction and compaction pressurePressures needed are at the low end of pressure used in a press, allowing for easy rearrangementModeling the lubricant in a rheometer could be expected to provide predictable results in a P/M press

Ejection Forces

Do we have a better lubricant for P/M ?

Breakaway Force FC0208 MP32 Base

1700

1900

2100

2300

2500

TSI

Lbs.

.75 Zinc Sterate 1953 2143 2320

.75 Acrawax 1977 2300 2486

.75 PS-1000b 1769 1793 1942

40 50 60

Strip Force FC0208 MP32 Base

1200

1400

1600

1800

2000

TSI

Lb

s.

.75 Zinc Sterate 1575 1797 1941

.75 Acrawax 1450 1558 1633

.75 PS-1000b 1208 1358 1483

40 50 60

Density FC0208 MP32 Base

6.75

6.80

6.85

6.90

6.95

7.00

TSI

Dens

ity G

/CC

.75 Zinc Sterate 6.77 6.89 6.98

.75 Acrawax 6.76 6.89 6.97

.75 PS-1000b 6.79 6.93 7.00

40 50 60

Hoeganaes A737SH Cu Graphite

Comparative Green Densities

6.60

6.70

6.80

6.90

7.00

7.10

7.20

7.30

30 40 50 60

TSI

De

ns

itie

s

0.30%APEX PS 1000b.75%Acrawax

Hoeganaes 85 HP Cu GraphiteComparative Green Densities

6.80

6.90

7.00

7.10

7.20

7.30

7.40

40 50 60

TSI

Den

siti

es

0.30%APEX PS 1000b.75%Acraw ax

Hoeganaes 85 HP Ni, GraphiteComparative Green Densities

7.00

7.05

7.10

7.15

7.20

7.25

7.30

7.35

7.40

40 50 60

TSI

Den

siti

es 0.25% APEXPS 1000 b

.75%Acraw ax

0.30% APEXPS 1000b

Hoeganaes Distalloy 4800A GraphiteComparative Green Densities

7.00

7.05

7.10

7.15

7.20

7.25

7.30

7.35

7.40

40 50 60

TSI

Den

siti

es

0.25% APEX PS 1000 b

.75%Acraw ax

0.30% APEX PS 1000b

Hoeganaes A1000C Ni GraphiteComparative Green Densities

7.10

7.15

7.20

7.25

7.30

7.35

7.40

40 50 60

TSI

Den

siti

es .75%Acraw ax

0.30% APEX PS 1000b

Domfer MP32 Cu GraphiteComparative Green Densities

6.406.506.606.706.806.907.007.107.20

30 40 50 60

TSI

Dens

ities

0.25% APEXPS 1000 b

0.30% APEXPS 1000b

0.4% APEXPS 1000 b

2NSt .75%

Domfer MP35 Cu GraphiteComparative Green Densities

6.70

6.80

6.90

7.00

7.10

7.20

7.30

30 40 50 60

TSI

Den

sitie

s

0.25% APEX PS 1000 b

0.30% APEX PS 1000b

0.4% APEXPS 1000 b

2NSt .75%

NAH ASC 100.29 GraphiteComparative Green Densities

7.00

7.05

7.10

7.15

7.20

7.25

7.30

7.35

40 50 60

TSI

De

ns

itie

s

0.30%APEX PS 1000b

.75%Acrawax

Kobelco 300 MC Ni GraphiteComparative Green Densities

7.00

7.05

7.10

7.15

7.20

7.25

7.30

7.35

40 50 60

TSI

De

ns

itie

s

0.25% APEX PS 1000 b

.75%Acrawax

Kobelco 300 ME Graphite MNSComparative Green Densities

7.00

7.05

7.10

7.15

7.20

7.25

7.30

7.35

40 50 60

TSI

De

ns

itie

s

0.25%APEX PS 1000 b.66%Acrawax

0.30%APEX PS 1000b

QMP 1001 Cu Graphite Comparative Green Densities

7.00

7.05

7.10

7.15

7.20

7.25

7.30

7.35

40 50 60

TSI

De

ns

itie

s

0.30%APEX PS 1000b

.75%Acrawax

Green density g/cc compared to conventional

lubricantsTonnage

Tsi

.25%

PS-1000b

.3%

PS-1000b

.4% PS-1000b

30 Up to .08 Up to .07 Up to .07

40 Up to .08 Up to .08 Up to .06

50 Up to .12 Up to .10 Up to .10

60 Up to .16 Up to .14 Up to .13

Green Density ConclusionsNice green density pick up is possible with a conventional pressNo delamination or micro-cracking observed up to 65 tsi with uniform hardness and porosity of part after sinteringSlope of compressibility curve has been shifted upwardProduction data is better than lab data, at low tonnage, due to friction (temperature) and speed (shear)We get green density improvements from both effective rearrangement and from lower use levels

Burn Out

The ideal lubricant burns out cleanly from the furnace and in the parts, all blisters and cracks would be eliminated

Quantity and rate of emission reduced

More parts through the furnace with less problems in less time

Minimize EPA concerns

Percent burned in disassociated ammonia

-

20.0

40.0

60.0

80.0

100.0

120.0

400 500 600 700 800 900 1000

Temperature in degrees F

Perc

ent b

urne

d

Lithium Stearate Zinc Stearate Acrawax C PS-1000b

200lbs. Metal, Gas evolution, Weight of Lube

0

0.2

0.4

0.6

0.8

1

1.2

1.4

400 F 500 F 600 F 700 F 800 F 900 F 1000 FTemperature in Degrees F

Lube

wei

ght

Lithium Sterate .75% Zinc Sterate .75% Acrawax .75% PS-1000b .3%

Weight of parts for equal gas evolution

0

200

400

600

800

1000

Weight of parts in Lbs.Lithium Sterate .75% PS-1000b .3% Zinc Sterate .75%

PS-1000b .3% Acrawax .75% PS-1000b .3%

Sintered Properties

General Improvements as green density improves

Sintered properties are enhanced with an effective lubricant

Hoeganaes A737 Cu GraphiteComparative Sintered Densities

6.50

6.60

6.70

6.80

6.90

7.00

7.10

7.20

30 40 50 60

TSI

Den

sitie

s

0.30% APEXPS 1000 b -SinteredDensity

0.75 %Acrawax -SinteredDensity

Hoeganaes A737 Cu GraphiteComparative Sintered Tensile Strength

110

120

130

140

150

160

170

180

190

30 40 50 60

TSI

KS

I

0.30%APEX Lube-SinteredTRS0.75 %Acrawax -SinteredTRS

Comparison of TRS/Sintered Density Ratio of FC0208 A737 base metal

14

16

18

20

22

24

26

30 40 50 60

TSI

Rat

io T

RS

/Sin

tere

d D

ensi

ty .30% ApexPS 1000bRatioTRS/Sintered Density

.75%ACRAWAX C RatioTRS/Sintered Density

Hoeganaes A737 Cu GraphiteComparative Sintered Hardness

32

34

36

38

40

42

44

46

48

30 40 50 60

TSI

HR

C

0.30%APEX Lube-SinteredHRC0.75 %Acraw ax -SinteredHRC

Comparison of Hardness/Sintered Density Ratio of FC0208A737 base metal

4

4.5

5

5.5

6

6.5

7

30 40 50 60

TSI

Har

dn

ess/

Sin

tere

d D

ensi

ty

Rat

io

.30% ApexPS 1000bRatioHardness/SinteredDensity

.75%ACRAWAX C RatioHardness/SinteredDensity

QMP A-1001 Cu GraphiteComparative Sintered Densities

6.65

6.75

6.85

6.95

7.05

7.15

7.25

7.35

30 45 60

TSI

Den

siti

es

0.30% APEXPS 1000 b

0.75 %Acraw ax

QMP A-1001 Cu GraphiteComparative Sintered Tensile Strength

120

130140

150160

170180

190200

210

30 45 60

TSI

KS

I

0.30% APEXPS 1000 b

0.75 %Acraw ax

Comparison of TRS/Sintered Density ratio of FC0208of QMP A1001

17

19

21

23

25

27

30 45 60

TSI

Rat

io o

f T

RS

/Sin

tere

d D

ensi

ty

.30%ApexPS1000bRatioTRS/SinteredDensity

.75%ACRAWAX CRatioTRS/SinteredDensity

QMPA-1001 Cu GraphiteComparative Sintered Hardness

70

75

80

85

90

95

30 45 60

TSI

HR

C 0.30% APEXPS 1000 b

0.75 %Acraw ax

Comparison of TRS/Sintered Density ratio- FC208

0

5

10

15

20

25

30

30 45 60

TSI

Ratio

of T

RS/S

inte

red

Dens

ity

.30% ApexPS 1000bRatioTRS/SinteredDensity

.75%ACRAWAXC RatioTRS/SinteredDensity

Kobelco MC300 base metal FN-0208 lube comparison

6.7

6.8

6.9

7

7.1

7.2

7.3

30 40 50 60

TSI

Sin

tere

d D

en

sit

y, g

/cc

Apex .3%SinteredDensity

Acrawax.75%SinteredDensity

Kobelco MC300 base metal FN-0208 Lube comparison

90

95

100

105

110

115

120

125

130

135

30 40 50 60

TSI

Sin

tere

d T

RS

, KS

I

Apex .3%SinteredTRS

Acrawax.75%SinteredTRS

Kobelco MC300 base metal FN-0208 lube comparison

13.5

14

14.5

15

15.5

16

16.5

17

17.5

18

18.5

30 40 50 60

TSI

TR

S/S

inte

red

de

ns

ity

ra

tio

Apex .3%TRS/SinteredDensity Ratio

Acrawax .75%TRS/SinteredDensity Ratio

Kobelco MC300 base metal FN-0208 lube comparison

68

70

72

74

76

78

80

82

84

30 40 50 60

TSI

Sin

tere

d H

ard

ne

ss

, HR

B Apex .3%SinteredApparentHardness

Acrawax.75%SinteredApparentHardness

Kobelco MC300 base metal FN-0208 lube comparison

10.1

10.3

10.5

10.7

10.9

11.1

11.3

11.5

30 40 50 60

TSI

HR

B/S

inte

red

De

ns

ity

Apex .3%HRB/SinteredDensity Ratio

Acrawax.75%HRB/SinteredDensity Ratio

Current Applications

To obtain green density comparable to die wall, hot compaction or double press without micro cracking or delaminationTo replace internal lubrication in conventional die wall lubrication applicationsTo modify a compressibility curve to fit a press

Current Applications Cont.

To debottleneck a furnace operationTo run high nickel formulas without blistering or cracksTo facilitate one step copper infiltration/sinteringTo obtain improved physical properties including TRS, hardness, and dimensional stability

Current Applications Cont.

Improve die wear

Improve surface appearance from furnace condensation

Reduction of scrap rate

Use Recommendations

.25%-.27% Apex PS-1000b for parts up to 3/8 inch

.3% Apex PS-1000b for parts 3/8 to 1 inch with moderate complexity

.35% Apex PS-1000b for parts with higher complexity or high surface area

.4% Apex PS-1000b for taller parts

Add .05% for non graphite containing mixes

Products Available

Apex PS-1000b

Apex PS-1000b mixed with customers choice of graphite (66.6%/33.3%)

Apex PS-1000b mixed with graphite plus other additives desired to be distributed (e.g. Cab-O-Sil, Flowguard, MnS, etc.)

Applications Not Recommended

FeSi and FeP formulas

6.8 to 7.0 green density applications

Using a Lubricant to Minimize Segregation and

DustingLubricant’s viscosity is a function of shear and temperatureLubricant is attracted to graphite, copper, nickel and iron powderWe can achieve excellent adhesion between fines and the base iron powder, if we get the viscosity low enough to spread uniformly We can lower the viscosity using heat and shear using a medium intensity mixer

Using a Lubricant to Minimize Segregation and

Dusting Cont.Lodige/ Littleford mixer

1) Preheat iron powder plus additives to

110C

2) Add .3% to .4% Apex PS-1000b, mix

for 4 minutes, screen

Dust resistance compared to untreated, excellent

Using a Lubricant to Minimize Segregation and

Dusting Cont.1% graphite mix - 58% loss without treatment, 8% loss with treatment

Results similar to binder treated mixes

Lubricant and binder are one and the same

A low level of PS-1000b gives all of the benefits of non-dusting plus benefits of high density, properties, etc.