LTCS ASTM A333 Grade 6 Vs ASTM A333 Grade 10

[MM01]

Dear All,

I am working on material selection for one 12 inch Liquid Propylene Pipeline operating at -41 C. The design temperature is -45 C. The MAOP is 17 barg and Design Pressure is 25 barg. The propylene is not corrosive and is refined. -41 C is the initial inlet temperature and outlet temperature is +4 C. The length of the pipeline is 12 kms. Pipeline design life is 50 years.
The pipeline starts from offshore berth and ends up at PP reactor. Considering the above conditions, I have selected LTCS material with nominal wall thickness and minor CA. Considering that, ASTM A333 Grade 6 is suitable choice. However, ASTM A333 Grade 6 is having lower SMYS.

However due to offshore installation procedure client has asked if ASTM A333 Grade 10 can be used as its SMYS is higher 450 MPa with same 12.7mm thickness.

a) I am a bit confused in this if ASTM A333 Grade 10 can be the suitable choice considering above conditions as its chemistry is different to Grade 6.

b) Any other material that can be used here for higher SMYS 450 MPa and Lower temperature stability (-46 C).

Thank you in advance.

 

[metengr]

The Grade 10 material under this specification will be impact tested at -60 deg C, which is lower than your MDMT. Assuming acceptable impact test results, and no restriction on the higher SMYS, this material can be used.

 

[MM01]

The Garde 10 will be tested at -60 C but for 12 inch pipe it will be hard to find as seam welding for this will require no addition of filler. Alrernately, API 5L X 60 or 52 can be used provided impact tested at -46 C.