Hastelloy C276 is an extremely versatile material that has found usage in a wide variety of severe environments. It has shown corrosion resistance to chloride-containing media, organic acids, oxidizing media, reducing acids, seawater and brine, and sulfuric flue gasses. Hastelloy C276 replaced Alloy C (UNS N10002), which contained slightly less chromium and molybdenum. The high nickel, molybdenum and tungsten content make it expensive when compared to austenitic stainless. By far, it is the most popular Super Alloy.
aMean coefficient of linear expansion between 77°F (25°C) and temperature shown.
Elevated Temperature Dynamic Modulus Properties
Temp.
Young’s Modulus
Shear Modulus
Poisson’s Ration
°F
103 ksi
103 ksi
70
31.30
11.81
0.33
100
31.18
11.75
0.33
200
30.77
11.57
0.33
300
30.35
11.40
0.33
400
29.92
11.23
0.33
500
29.42
11.05
0.33
Physical Constants
Density
lb/in3
0.321
g/cm3
8.89
Melting Range
°F
2,415 – 2,500
°C
1,325 – 1,370
Thermal Conductivity
Btu•in./ft2•h°F
67.9
W/m•°C
9.8
Specific Heat
Btu•lb•°F
0.102
J/kg•°C
427
Young’s Modulus
103 ksi
29.8
GPa
205
Shear Modulus
103 ksi
11.4
GPa
79
Permeability at 200 oersted (15.9 kA/m)
1.0002
Poisson’s Ratio
0.307
Mechanical Properties
Typical Room-Temperature Tensile Properties of Annealed Material
Product Form
Tensile Strength
Yield Strength (0.2% Offset)
Elongation
Hardness
ksi
MPa
ksi
MPa
%
Rb
Tubing
105.4
727
45.4
313
70
92
Plate
107.4
741
50.3
347
67
89
Bar
110.0
758
52.6
363
62
88
Sheet
115.5
796
54.6
376
60
86
Tensile properties of annealed plate.
Effect of cold work on the yield strength of
annealed plate.
Tensile properties of 33.5% cold-worked tubing.
Corrosion Resistance
Corrosion rates in sulfuric acid.
Corrosion rates in oxygen-saturated hydrochloric acid.
Corrosion rates in hydrochloric acid.
Corrosion rates in hydrochloric acid + 500 ppm Fe+++
Corrosion resistance in hydrochloric acid. The isocorrosion curves show temperatures and concentrations above which the corrosion rate exceeds 0.5 mm/a (20 mpy).
Comparative behavior of several nickel base alloys in sulfuric acid. The isocorrosion curves show temperatures and concentrations above which the corrosion rate exceeds 0.5 mm/a (20 mpy).
A summary iso-corrosion chart for 20 mpy (0.51 mm/a) data in hydrofluoric acid.
Corrosion Rates in Acid Solutionsa
Solution
Temperature
Corrosion Rate, mpy (mm/a)
°F
°C
Alloy C-276
Alloy 22
Alloy 625
Alloy 686
10% H2SO4
Boiling
Boiling
20 (0.51)
22 (0.56)
17 (0.43)
3 (0.08)
20% H2SO4
176
80
3 (0.08)
1 (0.03)
1 (0.03)
—
40% H2SO4
176
80
5 (0.13)
10 (0.25)
5 (0.13)
—
80% H2SO4
176
80
4 (0.10)
9 (0.23)
6 (0.15)
4 (0.10)
95% H2SO4
122
50
0.1 (0.003)
—
48 (1.2)
—
5% H2SO4 + 0.1% HCl
Boiling
Boiling
22 (0.56)
24 (0.61)
—
—
10% H2SO4 + 1% HCl
Boiling
Boiling
70 (1.78)
201 (5.11)
465 (11.68)
—
10% H2SO4 + 2% HCl
Boiling
Boiling
138 (3.51)
281 (7.14)
—
132 (3.35)
10% H2SO4 + 2% HCl
122
50
0.2 (0.005)
0.1 (0.003)
0.1 (0.003)
0 (0)
10% H2SO4 + 5% HCl
Boiling
Boiling
256 (6.50)
456 (11.58)
—
—
40% H2SO4 + 10% HCl
176
80
26 (0.66)
32 (0.81)
—
—
2% HCl
Boiling
Boiling
43 (1.09)
52 (1.32)
—
6 (0.15)
5% HCl
140
60
10 (0.25)
—
46 (1.17)
1.2 (0.30)
20% HCl
212
100
154 (3.91)
269 (6.83)
385 (9.78)
—
5% HCl + 2% HF
158
70
18 (0.46)
40 (1.02)
102 (2.59)
—
85% H3PO4
Boiling
Boiling
10 (0.25)
13 (0.33)
>180 (>4.57)
16 (0.41)
10% HNO3+ 3% HF
Boiling
Boiling
95 (2.41)
23 (0.61)
28 (0.71)
—
a168 h tests.
Corrosion Rates in Hydrochloric, Phosphoric and Acetic Acidsa
Solution
Temperature
Corrosion Rate, mpy (mm/a)
°F
°C
Alloy C-276
Alloy 26-6MO
Alloy 27-7MO
Alloy 22
Alloy 686
0.2% HCl
Boiling
Boiling
0.60 (0.02)
<0.1 (<0.003)
1.3 (0.03)
<0.1 (<0.003)
0.20 (0.005)
1% HCl
Boiling
Boiling
6.5 (0.17)
119 (3.02)
<0.1 (<0.003)
2.7 (0.07)
2.0 (0.05)
194
90
3.5 (0.09)
37.0 (0.94)
<0.1 (<0.003)
—
—
158
70
0.74 (0.02)
0.02 (<0.001)
<0.1 (<0.003)
—
—
5% HCl
158
70
13.2 (0.34)
142 (3.61)
150 (3.8)
18.8 (0.48)
9.8 (0.25)
122
50
0.5 (0.01)
43.4 (1.10)
5 (0.13)
1 (0.03)
0 (0)
85% H3PO4
Boiling
Boiling
10.4 (0.26)
114 (2.90)
27 (0.69)
13.0 (0.33)
16.2 (0.41)
194
90
0.20 (0.005)
10.6 (0.27)
<0.1 (<0.003)
0.21 (0.005)
0.18 (0.005)
80% CH3COOH
Boiling
Boiling
0.15 (0.004)
<0.1 (<0.003)
<1 (<0.03)
<0.1 (<0.003)
<0.1 (<0.003)
a192 h tests.
Corrosion Rates in Various Mediaa
Solution
Temperature
Corrosion Rate
°F
°C
mpy
mm/a
10% HNO3
Boiling
Boiling
15b
0.38b
10% HNO3+ 2% HCl
180
82
6.5
0.17
15% HNO3+ 3% HF
140
60
179
4.55
20% HNO3+ 2% HF
140
60
215
5.46
3% HF
176
80
53
1.35
10% HF
75
24
2
0.05
10% HF
176
80
28
0.71
Concentrated HF
75
24
1
0.03
Concentrated HF
176
80
34
0.86
20% H3PO4
Boiling
Boiling
<1
<0.03
60% H3PO4
Boiling
Boiling
1
0.03
85% H3PO4
212
100
<1
<0.03
20% H3PO4
Boiling
Boiling
10
0.25
99.9% CH3COOH + 0.1% NaCl
Boiling
Boiling
<1
<0.03
50% NaOH
Boiling
Boiling
1
0.03
10% HBr
176
80
<1
<0.03
10% HBr
Boiling
Boiling
<1
<0.03
10% NH3Br
176
80
0
0.00
10% NH3Br
Boiling
Boiling
0
0.00
aTest duration of 168 h except as noted. bTest duration of 24 h.
Nickel Systems provides high quality exotic grade materials that hold up in the toughest, most severe heat and corrosive environments. With our large inventory of specialty fasteners in stock, we are always ready to answer the call to serve the most challenging applications.