Inconel 625

INCONEL 625 TECHNICAL DATA

Type Anslysis

Element

Min

Max

Carbon

0.10

Nickel

Bal.

Chromium

20.0

23.0

Iron

5.00

Silicon

0.50

Manganese

0.50

Sulfur

0.015

Phosphorus

0.015

Molybdenum

8.00

10.0

Titanium

0.40

Cobalt

1.00

Columbium + Tantalum

3.15

4.15

Aluminum

0.40

Description

Alloy 625 is a nonmagnetic , corrosion – and oxidation-resistant, nickel-based alloy. Its outstanding strength and toughness in the temperature range cryogenic to 2000°F (1093°C) are derived primarily from the solid solution effects of the refractory metals, columbium and molybdenum, in a nickel-chromium matrix. The alloy has excellent fatigue strength and stress-corrosion cracking resistance to chloride ions. Some typical applications for alloy 625 have included heat shields, furnace hardware, gas turbine engine ducting, combustion liners and spray bars, chemical plant hardware, and special seawater applications.


Corrosion Resistance

Alloy 625 has withstood many corrosive environments. In alkaline, salt water, fresh water, neutral salts, and in the air, almost no attack occurs. The nickel and chromium provide resistance to oxidizing environments. Nickel and molybdenum provide for resistance to nonoxidizing atmospheres. Pitting and crevice corrosion are prevented by molybdenum. Niobium stabilizes the alloy against sensitization during welding. Chloride stress-corrosion cracking resistance is excellent. The alloy resists scaling and oxidation at high temperatures.

Average Dynamic Modulus of Elasticity *

Form

Condition

Test Temp.,
F(C)

Average Dynamic Modulus of
Elasticity, psi x 10(6) (MPa)

Plate,
3/8 in. (9.5 mm)
thick

Annealed at
1925°F (1052°C),
rapid cooled

Room
200 (93)
400 (204)
600 (316)
800 (427)
1000 (538)
1200 (649)
1400 (760)
1600 (871)
1800 (982)

30.2 (208,000)
29.2 (201,000)
28.8 (199,000)
27.7 (191,000)
26.7 (184,000)
25.6 (176,000)
24.3 (168,000)
22.8 (157,000)
21.2 (146,000)
18.7 (129,000)

* Average of five tests at each temperature.


Average Hardness and Tensile Data, Room Temperature

Condition

Form

Ultimate
Tensile
Strength,
ksi (MPa)

Yield
Strength
at 0.2%
offset,ksi (MPa)

Elongation
in 2″
percent

Hardness,
Rockwell

Annealed at
1925°F (1052°C),
rapid cooled

Sheet
0.014-0.063″
thick

132.0 (910)

67.9 (468)

47

B94

Annealed at
1925°F (1052°C),
rapid cooled

Sheet,*
0.0.78-0.155″
thick

131.5 (907)

67.4 (465)

45

B97

Annealed at
1925°F (1052°C),
rapid cooled

Plate,***
1/4″
1/2″
3/4″
1.00″
1-1/2″
1-3/4″


132.0 (910)
130.0 (896)
132.3 (912)
127.2 (877)
127.3 (878)
128.0 (883)


65.5 (452)
67.0 (462)
80.0 (552)
75.3 (519)
73.7 (508)
66.0 (455)


46
44
44
42
43
44


B94
B98
B98
B97
B97
C20

*Based on average of 146 tests
**Based on average of 67 tests.
***Based on average of 4 or less tests.

Average Tensile Data, Room Temperature*

Form

Aging Temperature,
F (C)

Aging Tme, hrs.

Ultimate
Tensile
Strength,
Ksi (MPa)

Yield
Strength
at 0.2%
offset,
Ksi (MPa)

Elongation
in 2 in.,
(50.8 mm),
percent

Plate,
1/2 in. (12.7 mm)
thick

Annealed**

127.7 (880)

66.2 (456)

46

1200 (649)

1000
4000
8000
16000

165.0 (1138)
163.6 (1128)
164.2 (1132)
165.4 (1140)

122.3 (843)
117.9 (813)
117.8 (812)
118.5 (817)

28
24
18
12

1400 (760)

1000
4000
8000
16000

142.9 (985)
145.5 (1003)
142.6 (983)
140.4 (968)

95.5 (658)
104.1 (718)
97.4 (672)
96.1 (663)

17
12
13
12

1600 (871)

1000
4000
8000
16000

130.0 (896)
130.0 (896)
127.0 (876)
128.4 (885)

68.3 (471)
66.4 (458)
63.7 (439)
63.4 (437)

30
29
26
32

*Average of three tests from a single heat.
**1875F (1024C), rapid cooled.

Average Rupture Data, Sheet*

Test Temperature,
°F(°C)

Average Rupture Strength, ksi (MPa)
for Time Indicated

10 hrs

100 hrs

1000 hrs

1200 (649)
1400 (760)
1600 (871)

82 (565)
36 (248)
12 (83)

71 (490)
27 (186)
6.7 (46)

60 (414)
20 (138)**
3.7 (26)**

*Annealed at 1925°F (1052°C), rapid cooled.
**Extrapolated

Hot Working
Hot working may done at 2100°F (1149°C) maximum furnace temperature. Care should be exercised to avoid frictional heat build-up which can result in overheating, exceeding 2100°F (1149°C). Alloy 625 becomes very stiff at temperatures below 1850°F (1010°C). Work pieces that fall below this temperature should be reheated. Uniform reductions are recommended to avoid the formation of a duplex grain structure. Approximately 15/20% reduction is recommended for finishing.

Cold Forming
Alloy 625 can be cold formed by standards methods. When the material becomes too stiff from cold working, ductility can be restored by process anneal.

Machineability
Low cutting speeds, rigid tools and work piece, heavy equipment, ample coolant and positive feeds are general recommendations.

Carbide tools should have smaller angles than high-speed tools and operating speeds can be higher. A sulfur-based cutting fluid is recommended. Thoroughly clean work piece after machining to prevent surface contamination during subsequent heat treating. Chlorine additives would be an alternative.

Weldability
Welding can be accomplished by the gas-shielded processes using a tungsten electrode or a consumable electrode. Postweld heat treatment of the weld are not necessary to maintain corrosion resistance. Heavy restrained sections can be welded and the weld’s mechanical properties follow the same trends as base metal properties. Standard practices such as clean surfaces, good joint alignment, U-joints for thicker sections, etc., should be followed.