High Temp Metals 800-500-2141

HAYNES 188 TECHNICAL DATA


Type Analysis | Description | Application | Workability | Physical Properties

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)

Haynes 188 - Current Inventory Stock