yosamitysamm
Mechanical
- Apr 1, 2009
- 28
Hi All,
I have recently come across an issue with G40.21-38W material and I was wondering if anyone else has come across this problem and what steps they took.
On 2 seperate tanks I have recently worked on I have received material specified as 38W on the MTR. However on closer inspection it does not meet the additional chemistry requirements of API 650 Table 4.1. On the first tank I caught it before the material was used and we had it replaced, however, on the second tank I caught it during my final review. Now I have a tank where 70% of the shell material is not approved per API 650. My concern is I don't know if my tank now meets my MDMT of -40F. No impact testing of the plates has been done as it was impact test except to -40F. I also don't have any crops or cutouts that I can send for testing.
The specific item that the material fails is the Vanadium to Nitrogen ratio. API 650 specifies a minimum ratio of 4:1 but I have a ratio less than that. Any metalugists out there who know the significance of this ratio?
I have recently come across an issue with G40.21-38W material and I was wondering if anyone else has come across this problem and what steps they took.
On 2 seperate tanks I have recently worked on I have received material specified as 38W on the MTR. However on closer inspection it does not meet the additional chemistry requirements of API 650 Table 4.1. On the first tank I caught it before the material was used and we had it replaced, however, on the second tank I caught it during my final review. Now I have a tank where 70% of the shell material is not approved per API 650. My concern is I don't know if my tank now meets my MDMT of -40F. No impact testing of the plates has been done as it was impact test except to -40F. I also don't have any crops or cutouts that I can send for testing.
The specific item that the material fails is the Vanadium to Nitrogen ratio. API 650 specifies a minimum ratio of 4:1 but I have a ratio less than that. Any metalugists out there who know the significance of this ratio?
