You can
send RFQs by filling out the RFQ form below. Or you can
fax RFQs to 800-707-3439. We will get back to you ASAP.
* Inconel/Incoloy and Monel are
Registered Trademarks of Special Metals Corporation and its subsidiaries.
Inconel 625 Technical Data
Description: Inconel 625 is a nickel-chromium-molybdenum alloy
with an addition of niobium. The addition of molybdenum acts with the niobium
to stiffen the alloy matrix, providing a high strength without a strengthening
heat treatment. The alloy resists a wide range of corrosive environments and
has a good resistance to pitting and crevice corrosion. Inconel 625 is used in
chemical processing, aerospace and marine engineering oil & gas, pollution
control equipment and nuclear reactors.
Applications:
Some typical applications for Inconel 625
have included heat shields, furnace hardware, gas turbine engine ducting,
combustion liners and spray bars, chemical plant hardware, and special
seawater applications.
Specifications:
Bar
ASTM B 446, ASME SB 466, AMS 5666, ISO 9723, VdTUV 499, BS 3076 NA21, EN
10095, DIN 17752, ASME Code Case 1935
Rod
ASTM B 446, ASME SB 466, ISO 9723, VdTUV 499, BS 3076 NA21, EN 10095, DIN
17752, SME Code Case 1935
Wire
AMS 5837, ISO 9724, DIN 17753
Forging Stock
ASTM B 564, ASME SB 564, AMS 5666, ISO 9725, SME Code Case 1935, DIN 17754
Plate
ASTM B 443, ASME SB 443, AMS 5599, AMS 5869, MAM 5599, ISO 6208, VdTUV
499, BS 3072 NA21, EN 10095, DIN 17750, ASME Code Case 1935
Sheet
ASTM B 443, ASME SB 443, AMS 5599, AMS 5869, MAM 5599, ISO 6208, VdTUV
499, BS 3072 NA21, EN 10095, DIN 17750, ASME Code Case 1935
Strip
ASTM B 443, ASME SB 443, AMS 5599, AMS 5869, MAM 5599, ISO 6208, VdTUV
499, EN 10095, DIN 17750, ASME Code Case 1935
VdTUV 499, ISO 6207, DIN 17751, ASME Code Case 1935
Fittings
ASTM B 366, ASME SB 366
Other
UNS N06625, W. Nr 2.4856, ISO NW6625, NACE MR-01-75, INCONEL 625
(trademark)
Chemical
Composition:
Ni
Fe
Cr
Si
Mo
Mn
C
Max
5.0
23.0
0.50
10.0
0.50
0.10
Min
58.0
20.0
8.0
Typical Mechanical Properties:
Material
Ultimate Tensile Strength (psi)
0.2% Offset Yield Strength (psi)
Elongation in 50.8mm (%)
Hardness, Rockwell
Alloy 625
130,000
68,000
42
B65
Nominal Mechanical Properties in the annealed
condition
Corrosion & Oxidation Resistance:
Inconel 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.
The high level of chromium and molybdenum in Alloy
625 provides a high level of pitting and crevice corrosion resistance to
chloride contaminated media, such as seawater, neutral salts, and brines.
Typical Data in Chloride
Solutions:
Crevice Test in
10 Percent Ferric Chloride
Alloy
316
Alloy
625
Onset Temperature
Degrees F (Degrees C)
for Attack in ASTM Procedure G-48
<32
(<0)
104-113
(40-45)
Panel Exposures in Seawater:
Panel Location Onset Temperature
Alloy
316
Alloy
625
Flowing Seawater
Crevice Attack
1 Month
No Attack
18 Months
Tidal Zone
Crevice Attack
1 Month
No Attack
18 Months
Partial Mud Burial
Crevice Attack
1 Month
No Attack
18 Months
The alloy is resistant to a
variety of corrosive media from highly oxidizing to moderately reducing.
Tests in geothermal brines
indicate Alloy 625 is highly resistant to hot geothermal fluids comparable to
Titanium Grade 2.
Tests in simulated flue gas
desulfurization environments show Alloy 625 highly resistant to the
environment in comparison to alloys such as Alloy 316 and comparable to Alloy
276.
The following data are
illustrative. Typical corrosion rates are in mils/year (mm/a).
Boiling Organic Acid Solutions:
Alloy
45% Formic
10% Oxalic
88% Formic
99% Acetic
Alloy 625
5.0 (0.13)
6.0 (0.15)
9.0 (0.23)
0.4 (0.01)
Alloy 316
11 (0.28)
40 (1.02)
9.0 (0.23)
2.0 (0.05)
Dilute Reducing Acids — Boiling
Solutions*
Alloy
1% Sulfuric
5% Sulfuric
10% Sulfuric
1% Hydrochloric
Alloy 625
2.2 (0.06)
8.9 (0.23)
25.3 (0.64)
36.3 (0.92)
Alloy 316
25.8 (0.65)
107 (2.72)
344 (8.73)
200 (5)
* Sulfuric acid test samples
activated before tests and hydrochloric acid test samples tested without
activation.
Miscellaneous Environments:
Environment
Alloy 625
Alloy 316
20% Phosphoric Acid
.36 (<0.01)
6.96 (0.18)
10% Sulfamic Acid
4.80 (0.12)
63.6 (1.61)
10% Sodium Bisulfate
3.96 (0.10)
41.6 (1.06)
Chloride Stress Corrosion
Cracking Resistance:
Test
Alloy 625
Alloy
316
Alloy 20
42% Magnesium Chloride
No Cracks
1000 Hours
Cracks
<24 Hours
Cracks
<100 Hours
26% Sodium Chloride
No Cracks
1000 Hours
Cracks
600 Cracks
No Cracks
1000 Cracks
Oxidation Resistance: Alloy 625 has excellent oxidation and scaling resistance at temperatures
up to 2000Degrees F (1093Degrees C). It is superior to many other high
temperature alloys under cyclic heating and cooling conditions.
Pickling:
Sodium hydride baths are necessary to descale this alloy. After the sodium
hydride treatment, the material should be immersed in a sulfuric acid bath
165 Degrees F (74 Degrees C) for approximately 3 minutes. A 25-minute immersion in a
nitric-hydrofluoric bath 145 Degrees F (63 Degrees C) is then necessary. Rinse. Sulfuric
solution: 16% by weight, H2SO4. Nitric solution: 8% HNO3 by weight and 3% HF
by weight. Acid etching for macro-inspection-expose material electrolytically
to a 3-to-1 HCl to HNO3 solution, saturated with CuCl2 at a current density of
0.645 amp/in (25.4 A/m).
Heat Treatment:
Inconel 625 has three basic heat treatments:
(1)High Solution Anneal - 2000/2200 Degrees F (1093/1204 Degrees C), air quench or
faster.
(2)Low Solution Anneal - 1700/1900 Degrees F (927/1038 Degrees C), air quench or
faster.
(3)Stress Relieve - 1650 Degrees F (899 Degrees C), air quench.
The time at the above temperatures depends on volume and section thickness.
Strip, for example, would require shorter times than large sections.
Temperatures for treatments No. 1 and 2 are generally held for 1/2 to 1 hour,
1 to 4 hours for treatment No. 3.
Treatment No. 1 is not commonly used for applications below 1500 Degrees F (816
Degrees C). It
is generally used above 1500 Degrees F and where resistance to creep is important. The
high solution anneal is also used to develop the maximum softness for mild
processing operations such as cold rolling or drawing.
Treatment No. 2 is the used treatment and develops an optimum combination of
tensile and rupture properties from ambient temperatures to 1900 Degrees F (1038
Degrees C).
Ductility and toughness at cryogenic temperatures are also very good.
Treatment No. 3 is recommended for application below 1200 Degrees F (649
Degrees C) when
maximum fatigue, hardness, tensile and yield strength properties are desired.
Ductility and toughness at cryogenic temperatures are excellent. When a fine
grain size is desired for fatigue, tensile and yield strengths up to 1500
Degrees F
(816 Degrees C), treatment No. 3 is sometimes used.
Workability:
Hot Working
Hot working may done at 2100 Degrees F (1149 Degrees C) maximum furnace temperature. Care
should be exercised to avoid frictional heat build-up which can result in
overheating, exceeding 2100 Degrees F (1149 Degrees C). Alloy 625 becomes very stiff at
temperatures below 1850 Degrees F (1010 Degrees 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
Inconel 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.
Physical Properties:
Density:
0.305 Ib/in3
8.44 g/cm3
Specific Gravity:
8.44
Melting Range:
2350 Degrees - 2460 Degrees F
1280 Degrees - 1350 Degrees C
Magnetic Permeability:
75 Degrees F, 200 oersted 1.0006
Specific Heat:
0.098 Btu/lb.- Degrees F
410 Joules/kg- Degrees K
Electrical Resistivity:
0.098 Btu/lb.- Degrees F
410 Joules/kg- Degrees K
Temperature
Electrical Resistivity
microhm-cm
Degrees F
(Degrees C)
70
21
128.9
100
38
129.6
200
93
131.9
400
204
133.9
600
316
134.9
800
427
135.9
1000
538
137.9
1200
649
137.9
1400
760
136.9
1600
871
135.9
1800
982
134.9
2000
1093
133.9
Thermal Properties:
Temperature
Linear Coefficient of Thermal
Expansion (a) (Units of 10-6)
Thermal Conductivity (b) (c)
Degrees F
Degrees C
/ Degrees F
/ Degrees C
Btu-ft / ft2 h-Degrees
F
W/m-Degrees K
-250
-157
–
–
4.2
7.3
-200
-129
–
–
4.3
7.4
-100
-73
–
–
4.8
8.3
0
-18
–
–
5.3
9.2
70
21
–
–
5.7
9.9
100
38
–
–
5.8
10.0
200
93
7.1
12.8
6.3
10.7
400
204
7.3
13.1
7.3
12.6
600
316
7.4
13.3
8.2
14.2
800
427
7.6
13.7
9.1
15.7
1000
538
7.8
14.0
10.1
17.5
1200
649
8.2
14.8
11.0
19.0
1400
760
8.5
15.3
12.0
20.8
1600
871
8.8
15.8
13.2
22.8
1700
927
9.0
16.2
–
–
1800
982
–
–
14.6
25.3
(a) Average coefficient from 70
Degrees F (21 Degrees C) to temperature shown.
(b) Measurements made at Battelle Memorial Institute.
(c) Material annealed 2100 Degrees F (1149 Degrees C).
Modulus Data:
Temperature
Modulus of
Rigidity (G)
Elastic Modulus (E)
Poisson's
Ratio (a)
Degrees F
Degrees C
Units of 106
psi
Units Gpa
Units of 106
psi
Units Gpa
(µ)
70
21
11.4
79
29.8
205
0.308
200
93
11.2
77
29.2
200
0.310
400
204
10.8
75
28.4
195
0.312
600
316
10.5
72
27.5
190
0.313
800
427
10.1
70
26.6
185
0.312
1000
538
9.7
67
25.6
175
0.321
1200
649
9.2
63
24.4
170
0.328
1400
760
8.7
60
23.1
160
0.329
1600
871
8.2
57
--
--
--
(a) Poisson's ratio (m) computed
from the relation: µ = E-2G/2G
Impact Resistance Alloy 625 maintains high impact resistance at low temperatures as
shown below.
Typical Alloy 625 Impact
Properties:
Test Temperature
Orientation
Impact Energy (a)
Degrees F
Degrees C
Ft-lbs
Joules
85
30
Longitudinal
49
66
85
30
Transverse
49
66
-110
- 79
Longitudinal
44
60
-110
- 79
Transverse
41.5
56
-320
-196
Longitudinal
35
47
-320
-196
Transverse
35
47
(a) Charpy Keyhole Specimens
(Mean Value of 3 Tests)
Impact properties may be expected
to decrease with extended service in the 1200 Degrees to 1600 Degrees F
(649 Degrees to 871 Degrees C) range.