Type
Analysis
|
Element
|
Min
|
Max
|
|
Carbon
|
0.05
|
0.15
|
|
Manganese
|
--
|
1.25
|
|
Silicon
|
0.20
|
0.50
|
|
Phosphorus
|
--
|
0.02
|
|
Sulfur
|
--
|
0.015
|
|
Chromium
|
21.0
|
23.0
|
|
Nickel
|
20.0
|
24.0
|
|
Tungsten
|
13.0
|
15.0
|
|
Lanthanum
|
0.03
|
0.12
|
|
Boron
|
--
|
0.015
|
|
Iron
|
--
|
3.0
|
|
Cobalt
|
Bal.
|
Description
Haynes 188 is a
cobalt-based alloy which possesses a unique combination of properties.
It has excellent high temperature strength and oxidation resistance
to 2100°F (1150°C) combined with good post-aging
ductility.
Alloy 188 has average room temperature tensile
properties in the bright annealed condition of 137.2 ksi (946 MPa)
ultimate strength, 67.3 ksi (464 MPa) yield strength and 53%
elongation. At 1800°F (980°C) the alloy has ultimate and
yield strengths of 35.2 ksi (243 MPa) and 19.0 ksi (131 MPa),
respectively, with 59% elongation. Cryogenic temperatures do not
significantly affect the ductility of alloy 188, but strength levels
are increased markedly.
The excellent oxidation resistance of
Haynes 188 results from minute additions of lanthanum, which modifies the
protective oxide scale in such a manner that the oxide becomes
extremely tenacious and retards diffusion when exposed to
temperatures through 2100°F (1150°C).
Haynes 188 exhibits
good ductility after prolonged exposure at temperatures of 1200,
1400, and 1600°F (650, 760 and 870°C) for 16,000 hours.
Application
Because of its excellent
strength, ductility and oxidation resistance, Haynes 188 meets the
critical high-temperature material requiredments for gas turbine
applications as well as many of those in the airframe, chemical and
nuclear fields. Typical uses are as transition ducts, combustor cans,
spray bars, flame-holders and afterburner liners in jet engines.
Workability
Haynes 188 can be forged
and, because of its good ductility, can be readily cold formed. It
can be welded by both manual and automatic welding methods including
electron beam, gas tungsten arc (TIG) and resistance welding. Alloy
188 exhibits good restraint welding characteristics.
Heat-Treatment
Wrought
forms of Haynes 188 are furnished in the solution heat-treated
condition unless otherwise specified. Alloy 188 is normally solution
heat-treated at 2150°F +/-25°F (1177°C +/-14°C) and
rapid air cooled or water quenched. Bright annealed products are
cooled in hydrogen.
Cold-Work and
Aging
Because of its relatively high strain hardening
coefficient, Haynes 188 can be easily strengthened by cold
deformation. Strengthening is further enhanced by aging the
cold-worked structure near 1000°F (540°C) for a period of 4
to 16 hours. This combination of treatments increases both the room
and elevated tensile strength of alloy 188 sheet. Cold working prior
to aging significantly increases the rate of the aging reaction.
Microstructure
Haynes
188 has a stabilized face-centered-cubic matrix containing nominally
22% Cr, 0.05% La and 0.4% Si to promote oxidation resistance. W at
14% is added for solid solution strengthening. Strengthening is
further enhanced by the precipitation of M6C and
M23C6 carbides. Intermediate
temperature ductility is achieved by deterring the formation of a A2B
Laves-type phase through selective alloying.
Physical
Properties
|
Physical
Properties
|
°F
|
British
Units
|
°C
|
Metric
Units
|
|
Density
|
72
|
0.324 lb./in.(3)
|
22
|
8.98 g/cm(3)
|
|
Incipient
Fusion
Temperature
|
2375-
2425
|
|
1302-
1330
|
|
|
Electrical
Resistivity
|
70
|
39.6 microhm-in.
|
21
|
1.01 microhm-m
|
|
Mean
Coefficient
of Thermal
Expansion
|
70 to -400
|
5.4 microin./in.-°F
|
21 to -200
|
9.7 X 10(-6)m/m-K
|
|
70 to -200
|
5.8 microin./in.-°F
|
21 to -129
|
10.4 X 10(-6)m/m-K
|
|
70-0
|
6.2 microin./in.-°F
|
21 to -18
|
11.2 X 10(-6)m/m-K
|
|
70-100
|
6.2 microin./in.-°F
|
21-38
|
11.5 X 10(-6)m/m-K
|
|
70-200
|
6.6 microin./in.-°F
|
21-93
|
11.9 X 10(-6)m/m-K
|
|
70-400
|
7.0 microin./in.-°F
|
21-204
|
12.6 X 10(-6)m/m-K
|
|
70-600
|
7.4 microin./in.-°F
|
21-316
|
13.3 X 10(-6)m/m-K
|
|
70-800
|
7.8 microin./in.-°F
|
21-427
|
14.0 X 10(-6)m/m-K
|
|
70-1000
|
8.2 microin./in.-°F
|
21-538
|
14.8 X 10(-6)m/m-K
|
|
70-1200
|
8.6 microin./in.-°F
|
21-649
|
15.5 X 10(-6)m/m-K
|
|
70-1400
|
9.0 microin./in.-°F
|
21-760
|
16.2 X 10(-6)m/m-K
|
|
70-1600
|
9.4 microin./in.-°F
|
21-871
|
16.9 X 10(-6)m/m-K
|
|
70-1800
|
9.9 microin./in.-°F
|
21-982
|
17.8 X 10(-6)m/m-K
|
|
70-2000
|
10.3 microin./in.-°F
|
21-1093
|
18.5 X 10(-6)m/m-K
|
|
Thermal
Conductivity
|
100
|
75 Btu-in/ft²-hr-°F
|
38
|
10.8 W/m-K
|
|
400
|
100 Btu-in/ft²-hr-°F
|
204
|
14.4 W/m-K
|
|
600
|
112 Btu-in/ft²-hr-°F
|
316
|
16.1 W/m-K
|
|
800
|
125 Btu-in/ft²-hr-°F
|
427
|
18.0 W/m-K
|
|
1000
|
138 Btu-in/ft²-hr-°F
|
538
|
19.9 W/m-K
|
|
1200
|
152 Btu-in/ft²-hr-°F
|
649
|
21.9 W/m-K
|
|
1400
|
167 Btu-in/ft²-hr-°F
|
760
|
24.1 W/m-K
|
|
Thermal
Diffusivity
|
572
|
0.006 in²/sec
|
300
|
3.9 x 10(-6)m²/s
|
|
752
|
0.006 in²/sec
|
400
|
3.9 x 10(-6)m²/s
|
|
932
|
0.007 in²/sec
|
500
|
4.5 x 10(-6)m²/s
|
|
1112
|
0.007 in²/sec
|
600
|
4.5 x 10(-6)m²/s
|
|
1409
|
0.008 in²/sec
|
765
|
5.2 x 10(-6)m²/s
|
|
1652
|
0.008 in²/sec
|
900
|
5.2 x 10(-6)m²/s
|
|
2012
|
0.009 in²/sec
|
1100
|
5.8 x 10(-6)m²/s
|
|
Magnetic
Permeability
(Room Temperature)
|
1.01 at 200 oersteds
(15,900 A/m)
|
Dynamic Modulus of Elasticity
|
Test
Temp.,
°F(°C)
|
Dynamic
Modulus of
Elasticity, 10(6) psi(MPa)
|
Test
Temp.,
°F(°C)
|
Dynamic
Modulus of
Elasticity, 10(6) psi(MPa)
|
|
-300 (-184)
|
36.1 (249)
|
600 (136)
|
30.2 (208)
|
|
-250 (-157)
|
35.8 (247)
|
800 (427)
|
28.9 (199)
|
|
-200 (-129)
|
35.4 (244)
|
1000 (538)
|
27.6 (190)
|
|
-100 (-73)
|
34.8 (240)
|
1400 (760)
|
24.9 (172)
|
|
86 (30)
|
33.6 (232)
|
1800 (982)
|
22.3 (154)
|
|
400 (31.5)
|
31.5 (217)
|
|
Average Tensile Data, Sheet*
|
Test
Temp.,
°F(°C)
|
Ultimate
Tensile
Strength,
ksi(MPa)
|
Yield
Strength
at 0.2% offset,
ksi(MPa)
|
Elongation
in
2",
%
|
|
70 (21)
|
137.2 (946)
|
67.3 (464)
|
53
|
|
1000 (538)
|
108.5 (748)
|
42.0 (290)
|
61
|
|
1200 (649)
|
103.3 (712)
|
39.7 (274)
|
59
|
|
1400 (760)
|
89.9 (620)
|
38.9 (268)
|
63
|
|
1600 (871)
|
60.0 (414)
|
35.9 (248)
|
64
|
|
1800 (982)
|
35.2 (243)
|
19.0 (131)
|
59
|
|
2000 (1093)
|
18.7 (129)
|
9.3 (64)
|
32
|
*Bright annealed sheet
0.029-0.050". Strain rate was 0.005 in/in/minute to 0.2% yield
point and .05 in/in/minute to failure.
Average Rupture Data
|
Form
|
Condition
|
Test
Temp.
°F(°C)
|
Average
Rupture Life Strength
for Time Indicated, ksi(MPa)
|
|
10 hrs
|
100 hrs
|
1000 hrs
|
|
Sheet,
0.029-0.050"
thick
|
Solution
heat
treated
|
1400
(760)
1600(871)
1800(982)
|
43.0 (296)
21.0
(145)
9.1 (63)
|
32.0 (221)
14.4
(99)
5.4 (37)
|
23.0 (159)
9.4
(65)
2.4 (17)
|
Average Creep Data
|
Form
|
Condition
|
Test
Temp.
°F(°C)
|
Creep
Elongation,
percent
|
Average
Stress in Ksi (MPa) to Cause
Creep Elongation in Indicated
Time
|
|
10 hrs
|
100 hrs
|
1000 hrs
|
|
Sheet,
0.029-0.050"
thick
|
Solution
heat
treated
|
1400
(760)
1500(816)
1600(871)
1700(927)
1800(982)
|
0.5
1.0
0.5
1.0
0.5
1.0
0.5
1.0
0.5
1.0
|
22.5(155)
25.5(176)
15.5(107)
17.6(121)
10.7(74)
12.2(84)
7.3(50)
8.2(57)
4.9(34)
5.6(39)
|
16.4(113)
18.5(128)
11.1(77)
12.6(87)
7.5(52)
8..4(58)
4.9(34)
5.6(39)
3.1(21)
3.6(25)
|
11.7(81)
13.3(92)
7.8(54)
8.8(61)
5.0(34)
5.7(39)
3.1(21)
3.6(25)
1.8(12)
2.1(14)
|
|
