Commercially pure (C.P.) titanium and titanium alloys offer excellent resistant to many commonly encountered corrosive media. However, these materials are currently in very limited supply. Thus, designers are being forced to consider alternate corrosion resistant materials.
Nickel-chromium-molybdenum corrosion-resistant alloys such as INCONEL alloys C-276, 22, 686, INCOLOY alloy 25-6MO, 27-7MO, Allegheny Ludlum AL6XN, Krupp VDM alloys 31 and 59, Haynes Hastelloy C-2000 are excellent candidates for this purpose.
|
%Ni-%Mo |
Cost Ratio |
PREN |
CPT (ASTM G48C) |
CCT (ASTM G48D) |
CPT (Green Death) |
CCT (Green Death) | |
|
INCOLOY 25-6MO |
25-6 |
1 |
35.8 |
70℃ |
35℃ |
60℃ |
45℃ |
|
AL 6XN |
24-6 |
1 |
36.4 |
70-75℃ |
35℃ |
65℃ |
50℃ |
|
VDM 31 |
31-6 |
1.4 |
42.6 |
75℃ |
45℃ |
55℃ |
50℃ |
|
INCOLOY 27-7MO |
27-7 |
1.1 |
43.0 |
>85℃ |
50℃ |
80℃ |
65℃ |
|
INCONEL C-276 |
57-16 |
2.0 |
45.2 |
>85℃ |
50℃ |
>Boiling |
90℃ |
|
HASTELLOY C-2000 |
57-16 |
2.3 |
47.0 |
>85℃ |
110℃ |
<125℃ | |
|
INCONEL 22 |
58-13 |
2.1 |
46.5 |
>85℃ |
75℃ |
>120℃ |
120℃ |
|
VDM 59 |
59-16 |
2.3 |
47.0 |
>85℃ |
130℃ | ||
|
INCONEL 686 |
57-16 |
2.3 |
50.8 |
>85℃ |
>85℃ |
>135℃ |
135℃ |
PREN = %Cr + 1.5(%Mo + %W) + 30(%N)