Not all 6Mo is the same
NORSOK M-630 Piping Data standard lists at least 2 6-moly alloys
Traditionally Swagelok has used 254 6Mo but through our latest manufacturing developments and material sourcing, we can now offer 6XN 6Mo.
|
Alloy |
UNS |
Ni |
Cr |
Mo |
Cu |
N |
|
254 |
S31254 |
17.5-18.5 |
19.5-20.5 |
6.0-6.5 |
0.50-1.00 |
0.18-0.22 |
|
6XN, 25-6HN |
N08367 |
23.5-25.5 |
20.0-22.0 |
6.0-7.0 |
0.75 max. |
0.18-0.25 |
6XN versus 254
6XN has 6% higher Ni content, Higher CR and lower CU content. This provides several advantages:-
- Better corrosion resistance
- More resistant to Sigma phase formation
- Improved mechanical properties
- Higher ASTM temperature rating
The Pitting Resistance Equivalent Number (PREN) is an industry recognized way to determine the corrosion resistance of a material.
The chart below shows that 6XN is more corrosive resistant than 254 due to the higher Cr content.
