Near Full Density As Sintered
Powdered Metal (P/M) Parts
Produced From Water Atomized
Powder With Properties
Comparable To Wrought Steel
Richard R. Phillips - Engineered Pressed
Materials
Dennis Hammond - APEX Advanced
Technologies, LLC 1
Key Features of the Technology
• Water atomized powder
• Low alloy steel -100 mesh
• >99.5% theoretical density
• Properties comparable or superior to
wrought steel
• Standard tooling/ conventional pressing
• Normal compaction range
2
Key Features of the Technology
Continued
• High temperature sintering < 2500F
(atmospheric or vacuum)
• Conventional steel heat treating
• Post heat treating operations similar to
wrought processing
3
Lubricant Requirements For Near
Full Density P/M Parts
•
•
•
•
Increase green density
Mobility of the lubricant
Effective removal of the lubricant
Excellent dimensional stability
4
High Green Density with Standard
Equipment
• Reduced level of lubricant, typical use level .25%.4%
• Green Densities 7.2-7.4 g/cc typical for common
formulas
• Micro cracking and delamination eliminated
• Green density increased due to reduced volume of
lubricant and better fit of particles resulting from
mobility of the lubricant
• Lubricant is more effective
5
Mobility of Lubricant
• Lubricant transforms with shear, pressure,
and friction from a solid to a viscous liquid
at relatively low pressure (~ 4 tsi with
shear)
• Mobility allows for effective rearrangement
of metal particles
• Mobility allows for lubricant to be forced to
the die wall as well as hydrostatic
environment within the compact
6
Effective Removal of the
Lubricant
• Environmentally friendly,contains no metal
• Staggered decomposition rate
• Up to 70% less gas trying to exit the part at
peak decomposition relative to conventional
lubricants
• Elimination of cracking and blistering with
high nickel formulas
• Elimination of recondensation of lubricant
on part surfaces
7
Excellent Dimensional Stability
•
•
•
•
•
•
•
No micro cracks or delamination
Small uniform pore size in the green state
No unplanned density gradients in the part
Relatively stress free green part
Density split eliminated
Uniform, predictable shrinkage
Enhanced sintering efficiency
8
Other Part Attributes
• Good surface finish
• Good ejection with reduced level of
lubricant
• Due to the high green densities achieved,
excellent green strength is also obtained
9
Density Gradient – Shape Retention
10
Density Gradient – Shape Retention
TOP
A
B
C
One direction
compaction
B
C
Dual
direction
compaction
Elimination of
Die Wall
Friction and
Density Split
A
BOTTOM
Dg = 7.0 g/cm³
Df = 7.82 g/cm³
7.82
≈ 11.7% Increase in D
7.0
≈ 3.8 Δ ≈ 0.038”/in.
L
;
11
DENSITY (g/cc)
Pressure/Density Curve FLN-0706
7.80
7.40
7.00
6.60
6.20
20
30
40
50
60
Mpa
276
414
552
690
828
Green
6.38
6.79
7.04
7.19
7.29
Sintered 7.81
7.82
7.82
7.81
7.81
12
Materials and Processing
(Experiments)
Standard
MPIF
ASTM
Comments
Density
42
B328
Modified Method
Hardness Macro
43
E18
Impact Notched
E23
Impact Un-notched
40
E23
Modulus of Elasticity
10
E8
Ultimate Tensile
Strength
10
E8
Yield Strength
10
E8
Elongation
10
E8
Microstructure
Photomicrographs
E3
E883
13
Test Alloys
•Hoeganaes Ancorsteel 85HP and 150HP formulated to
provide a resulting alloy with 0.56%Carbon and Nickel
contents between 2 and 6.6%.
•Pressed at 276 (20),414 (30), 552 (40) ,690 (50), and
828 (60) MPa (TSI).
•Vacuum or Atmosphere High Temperature Sintering
•Heat Treated to Commercial Wrought Steel Properties
14
Tensile Data
Sample
Type
Density
, g/cc
UTS, MPa
(103 psi)
0.2% YS,
MPa (103 psi)
% Elong.
Pressed
7.81
1,486 (215)
1,296 (187)
3.1
Machined
7.79
1,383 (200)
1,304 (189)
2.9
Pressed
7.59
1,446 (209)
1,205 (175)
4.0
Machined
7.57
1,414 (205)
1,248 (181)
4.2
Pressed
7.82
1,182 (171)
955 (138)
5.2
Machined
7.79
987 (143)
939 (136)
3.5
Pressed
7.46
1,051 (152)
685 (99)
4.4
Machined
7.57
1,314 (190)
1,211 (176)
4.9
Pressed
7.76
1,062 (154)
803 (116)
8.6
Machined
7.79
1,036 (150)
787 (114)
4.2
Pressed
7.60
1,188 (172)
690 (100)
4.0
Machined
7.57
1,089 (158)
730 (106)
7.4
% ROA
9.34
10.48
11.51
15.92
13.48
15.19
Mod of Elas.,
GPa (106 psi)
Hardness
HRC
188 (27.3)
43.5
182 (26.4)
45.0
158 (22.9)
39.7
162 (23.5)
38.7
183 (26.6)
34.3
192 (27.8)
35.4
141 (20.4)
28.0
164 (23.8)
37.5
170 (24.6)
32.0
171 (24.8)
32.6
136 (19.8)
36.7
135 (19.6)
32.0
15
Comparison to Wrought Tensile Data
Grade
UTS
MPa (103 psi)
0.2% Y.S.
MPa (103 psi)
% Elongation
Hardness,
HRC Scale
ANP FLN-0706
Range of Data
1,486 (215.4)
1,383 (200.5)
1,296 (187.9)
1,304 (189.1)
3.1/2.9
43.5/45.0
AISI 4140
1,449 (210)
1,346 (195)
14
45
AISI 4340
1,449 (210)
1,325 (192)
14
45
AISI 5140
1,304 (189)
1,228 (178)
14
40
AISI 4150
1,573 (228)
1,484 (215)
9
47
AISI 5150
1,435 (208)
1,346 (195)
11
45
AISI 6150
1,401 (203)
1,325 (192)
10
46
16
Comparison to Wrought Tensile Data
Grade
UTS
MPa (103 psi)
0.2% Y.S.
MPa (103 psi)
% Elongation
Hardness,
HRC Scale
ANP FLN-0706
Range of Data
1,182 (171.3)
987 (143.1)
955 (138.4)
939 (136.1)
5.2/3.5
34.3/35.4
AISI 4140
1,021 (148)
917 (133)
18
33
AISI 4340
1,049 (152)
979.8 (142)
18
34
AISI 5140
911 (132)
800 (116)
20
28
AISI 4150
1,242 (180)
1,118 (162)
12
39
AISI 5150
980 (142)
911 (132)
18
31
AISI 6150
1,125 (163)
1,063 (154)
15
36
17
Comparison to Wrought Tensile Data
Grade
UTS
MPa (103 psi)
0.2% Y.S.
MPa (103 psi)
% Elongation
Hardness,
HRC Scale
ANP FLN-0706
Range of Data
1,062 (154.0)
1,036 (150.2)
803 (116.5)
787 (114.2)
8.6/4.2
32.0/32.6
AISI 4140
814 (118)
697 (101)
23
22
AISI 4340
911 (132)
800 (116)
24
20
AISI 5140
787 (114)
580 (84)
27
95 HRB
AISI 4150
876 (127)
807 (117)
20
27
AISI 5150
807 (117)
711 (103)
23
23
AISI 6150
814 (118)
738 (107)
22
23
18
Charpy Impact Comparison
Density, g/cc
FLN-0706
(No Notch), ft-lbf
FLN-0706
(Notched), ft-lbf
Wrought
(Notched), ft-lbf
7.8
50
7
12 - 17
7.6
55
6
7.8
77
13
7.6
67
11
7.8
84
7.6
70
36 - 56
77 - 87
19
Size Change/Coefficient of
Variance
Coefficient of Dimensional Variance (%)
Equal to the standard deviation divided by the
average multiplied by 100
Pressed Direction 0.17%
Perpendicular to Pressed Direction 0.084%
20
Cylinders
Back row in the as-molded condition.
Front row in sintered and heated condition.
OD = 1.880” , OAL = 1.755”, 1.500”, 0.750”, 0.500”
21
Processed Samples
Samples in molded, sintered and heat treated, and
machined condition. (7.81 g/cc, 45 HRC)
22
Gears, Pawls and Rollers
Back row in the as-molded condition.
Front row in sintered and heated condition.
23
Density
6.70 g/cc
7.41 g/cc
7.84 g/cc
(85% Theoretical Density)
(95% Theoretical Density)
(>99.5% Theoretical Density)
24
Future Analysis (Fatigue)
Stress Endurance values
for various sets of process
conditions
25
P/M and Other Process Costs
Machining & Precision
Casting
225%
Relative Cost
200%
Powder Forge
Double Press
&
Double Sinter
175%
High Velocity Compaction
(Double Press – Double Sinter)
150%
125%
Single Press &
Sinter
Warm Compaction
100%
High Velocity
Compaction
ActivatedTM
NanotechTM
Sinter
75%
7.0
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7.9
Density (g/cm3)
26
Conclusions
• ANPTM* processing of -100 mesh ferrous powder
alloys creates material properties similar to wrought
product.
• ANPTM utilizes conventional blending, tooling and
P/M molding capabilities.
• Lubricant choice plays a critical role.
• ANPTM is activated during high temperature sintering
resulting in densification > 99.5% of theoretical
(pore-free).
• ANPTM dimensional control is predictable and
uniform within < 0.2% variance.
ANPTM, ACTIVATEDTM NANOTECHTM are trademarks of Material Technologies, Inc.
*Patent Pending
27
Conclusions (cont.)
• ANPTM can utilize conventional wrought metal
processing to meet specific engineering design
requirements to enhance optimum product
performance.
– Machining without lubricant intrusion.
– Plating without impregnation.
– Salt Bath Processing
• Kolene Nu-tride
• Blueing
– Ferritic Nitrocarburizing (Atmosphere).
28
Conclusions (cont.)
• ANPTM parts can be pressed from 276 (20) to 828
(60) MPa (TSI) and still sinter to full density.
• Further development work will result in even greater
performance.
• Work continuing on a broader selection of alloys.
29