Inconel 718

INCONEL 718 TECHNICAL DATA

Type Anslysis

Element

Min

Max

Carbon

0.08

Manganese

0.35

Silicon

0.35

Phosphorus

0.015

Sulfur

0.015

Nickel + Cobalt

50.0

55.0

Chromium

17.0

21.0

Cobalt

1.00

Iron

Balance

Aluminum

0.35

0.80

Molybdenum

2.80

3.30

Titanium

0.65

1.15

Boron

0.001

0.006

Copper

0.15

Cb + Ta

4.75

5.50

Description

Alloy 718 is a precipitation hardenable nickel-based alloy designed to display exceptionally high yield, tensile and creep-rupture properties at temperatures up to 1300°F. The sluggish age-hardening response of alloy 718 permits annealing and welding without spontaneous hardening during heating and cooling. This alloy has excellent weldability when compared to the nickel-base superalloys hardened by aluminum and titanium. This alloy has been used for jet engine and high-speed airframe parts such as wheels, buckets, spacers, and high temperature bolts and fasteners.


Modulus of Elasticity (E)

Temperature

psi x 10(6)

MPa x 10(3)

°F

°C

70
200
400
600
800
1000
1200
1400
1600
1750

21
93
204
316
427
538
649
760
871
954

29.6
29.2
28.8
27.6
26.5
25.5
24.5
23.1
18.1
11.1

208
205
202
194
186
179
172
162
127
78

Heat Treatment

The following heat treatment should be used to obtain the best combination of tensile properties and stress rupture properties:
1 hr 1750°F to 1800°F (954 to 982°C) air cool + 8hr 1325°F (718°C) cool 100°F /hr to 1150°F (56 °C/hr to 621°C), hold 8 hrs and air cool.
To obtain the best room temperature and cryogenic tensile properties, the following heat treatment should be used:
1 to 2 hr 1950°F (1066°C), air cool + 8 hr 1325°F (718°C) cool 100°F/hr to 1150°F (56°C/hr to 621°C), hold 8 hr and air cool.

Elevated Temperature Tensile Tests
1/2″ bar stock

Test
Temperature

0.2%
Yield Strength

Tensile
Strength

%
Elongation 2″

°F

°C

ksi

MPa

ksi

MPa

200
400
600
800
1000
1200
1400

93
204
316
427
538
649
760

170
163
159
156
155
149
110

1172
1124
1096
1076
1069
1027
758

204
198
195
191
185
168
110

1407
1365
1344
1317
1276
1158
758

21.0
20.0
20.0
19.0
18.0
19.0
27.0

Heat Treatment: 1 hr – 1800°F, air cool + 8 hr-1325°F, cool 100°F/hr to 1150°F, hold 8 hr, air cool.

Stress Rupture Data

Test
Temperature

Stress for Rupture

°F

°C

100 Hours

1000 Hours

Smooth

Notch

Smooth

Notch

ksi

MPa

ksi

MPa

ksi

MPa

ksi

MPa

1100
1200
1300
1400

593
649
704
760

170
110
75
44

1172
758
517
303

220
195
130
63

1517
1344
896
434

130
85
55
25

896
586
379
172

205
170
80
35

1416
1172
552
241

Heat Treatment: 1 hr – 1850°F, air cool + 8 hr – 1325°F, furnace cool to 100°F/hr to 1150°F, hold 8 hr, air cool