Type
Analysis
|
Element
|
Min
|
Max
|
|
Carbon
|
0.08
|
0.16
|
|
Manganese
|
1.00
|
2.00
|
|
Silicon
|
--
|
1.00
|
|
Sulfur
|
--
|
0.03
|
|
Chromium
|
20.0
|
22.5
|
|
Nickel
|
19.0
|
21.0
|
|
Copper
|
--
|
0.50
|
|
Tungsten
|
2.00
|
3.00
|
|
Iron
|
Balance
|
|
Cobalt
|
18.5
|
21.0
|
|
Columbium*
|
0.75
|
1.25
|
|
Nitrogen
|
0.10
|
0.20
|
|
Molybdenum
|
2.50
|
3.50
|
|
Phosphorus
|
--
|
0.04
|
* plus Tantalum
Description
N-155 alloy has high temperature
properties which are inherent and do not depend upon age hardening.
It is recommended for applications involving high stresses at
temperatures up to 1500°F, and can be used up to 2000°F where
only moderate stresses are involved. It has good ductility, excellent
oxidation resistance, and can be readily fabricated and
machined.
N-155 is recommended for parts which must possess good
strength and corrosion resistance up to 1500°F. It is used in
numerous aircraft applications such as tail cones and tailpipes,
exhaust manifolds, combustion chambers, afterburners, turbine blades
and buckets, and bolts.
Physical
Constants:
Density - lb/cu in................................................... 0.298
kg/cu m................................................... 8249
Melting range.....................2350/2470°F (1288/1354°C)
Electrical resistivity
ohm-cir mil/ft at 72°F........................................... 558
microhm-mm at 22.2°C......................................... 930
Specific heat
Btu/lb-°F (70/212°F)........................................... 0.104
kJ/kg-K (21/100°C).............................................. 0.435
Thermal conductivity
|
Temperature
|
Btu-in/ft²-hr-°F
|
W/m-K
|
|
°F
|
°C
|
|
392
572
752
932
1112
|
200
300
400
500
600
|
101
110
120
129
139
|
14.6
15.9
17.3
18.6
20.0
|
Coefficient of thermal expansion:
|
Temperature
|
10(-6)/°F
|
K(-1)
|
|
70°F to
|
21.1°C to
|
|
212
392
572
752
932
1112
1292
1472
1652
1832
2012
|
100
200
300
400
500
600
700
800
900
1000
1100
|
7.90
8.50
8.51
8.58
8.98
9.32
9.60
9.81
9.98
10.14
10.28
|
14.2
15.3
15.3
15.4
16.2
16.8
17.3
17.7
18.0
18.3
18.5
|
Modulus of elasticity:
|
Temperature
|
psi
x 10(6)
|
MPa
x 10(3)
|
|
°F
|
°C
|
|
70
1000
1500
|
21.1
538
816
|
29.25
24.20
20.80
|
202
167
143
|
Heat
Treatment:
Solution Treatment:
Heat to
2100/2280°F, hold for 1 hour at heat, and cool rapidly. The best
ductility is obtained by treating at the lower temperature while
treating at the higher temperature produces the highest rupture
strength.
Aging Treatment:
Heat to
1400/1500°F, hold approximately 16 hrs at heat , and air cool.
Hardness Values:
Condition Brinell Rockwell
Hot worked................................................... 277 C 29
Solution Treated 2200°F (1204°C)
water quenched.......................................... 217 B 96
Solution Treated 2200°F (1204°C)
water quenched
+ aged 1500°F (816°C)............................ 230 C 20
Workability
Hot Working:
Forging of
ingots should be conducted from about 2200°F (1204°C) after
being thoroughly soaked. Hot rolling of finished sizes from
semifinished hot-worked material should be conducted at 2050/2150°F,
and the finishing temperature should be kept as high as pracitcal
under the hot working conditions.
Machining
A rigid setup,
low cutting speeds and ample coolant flow are recommended. Following
are suggested angles for single point tungsten carbide tools: 8 to
10° side rake angle, 5 to 8° back rake angle, 5 to 7° end
relief angle, 15 to 30° side cutting edge angle. Radius of nose
-1/32". The included angle of high speed drills should be ground
to 135 to 140°, with a clearance angle of 10°. Thin the webb
to about 1/3 the thickness of a standared drill.
Welding
N-155 can be welded
by metallic-arc, inert-gas-shielded arc, and solid-phase pressure
welding methods.
Corrosion
Resistance
In the solution-heat-treated
condition it has about the same resistance to nitric acid as does
stainless steel. At room temperature it has better resistance than
stainless steel to weak solutions of sulfuric and hydrochloric acids.
Typical
Mechanical Properties
Tensile Properties
Solution
Treated 2150°F (1177°C), air cooled.
|
Test
Temperature
|
Tensile
Strength
|
Yield
Strength
0.2% Offset
|
%
Elongation
in
2"
|
%
Reduction
of
Area
|
|
°F
|
°C
|
ksi
|
MPa
|
ksi
|
MPa
|
|
Room
1000
1200
1400
1600
1800
2000
|
Room
538
649
760
871
982
1093
|
118
93
80
60
38
19
10
|
314
641
552
414
262
131
69
|
59
44
42
38
26
18
--
|
407
303
290
262
179
124
--
|
40
37
35
35
37
38
45
|
50
48
47
42
42
50
60
|
Stress Rupture Properties
Solution
Treated 2200°F (1204°C), 1 hour, water quenched, + aged 16
hours 1400°F (760°C), air cooled.
|
Test
Temperature
|
Stress
for Rupture in
|
|
°F
|
°C
|
10 Hours
|
100 Hours
|
1000 Hours
|
|
ksi
|
MPa
|
ksi
|
MPa
|
ksi
|
MPa
|
|
1200
1350
1500
1650
|
649
732
816
899
|
65
38
26
18
|
448
262
179
124
|
52
30
18
10
|
359
207
124
69
|
38
23
14
7
|
262
159
97
48
|
| 
