IMPACT TESTING OF LPG STORAGE TANK

[manoj john]

Dear Experts,

We have an order from the client to fabricate LPG sphere storage tank as per ASME SEC VIII Div 1 2010 Ed. with client data sheet and drawings. The design data is as follows:

Des. pressure  (Int. & Ext.)  -     10.2 bar/FV

Des  temperature                -       -42 degree C./+90 Degree C.

MDMT                               -       - 42 degree C

Heat treatment                   -       Nil

Radiography                      -       100%

Charpy impact test            -        yes.

Material                            -        SA 516 Gr70 N

Inside dia                          -        11250 mm

Thickness                        -          27 mm

I would like to clarify :   1)  Why the heat treatment is not required since the impact test is there and thickness is above 16mm 

                           2)  Production test coupon for impact test is required or not as per code  OR can we exempt impact test with any of the code clauses UCS 66 and UG20.

                            

Please do reply.

Thanks and Regards.

Manoj

                                

[Chan, David]

Mr. Manoj,

Congratulations on receiving the LPG Sphere Tank order

As per the understanding that the design is based on ASME Code, the heat treatment is mandatory required as per UCS-56 where the thickness exceeds 1.5” or 38.1mm

There is no relationship between the mandatory Impact test for heat treatment to be carried out

Impact tests is required based on the design temperature because of the service / contents

 

I hope the above  helps and await other experts who could provide you with a much better understanding

 

Thank you

Best Regards

 

David Chan

Sinagpore

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[Prakash Hegde]

Hi! My c omments given below in RED Regards Hegde   --- On Tue, 5/3/13, manoj john <manoj...@gmail.com> wrote:

From: manoj john <manoj...@gmail.com> Subject: [MW:16941] IMPACT TESTING OF LPG STORAGE TANK

To: material...@googlegroups.com Date: Tuesday, 5 March, 2013, 9:23 AM

Dear Experts, We have an order from the client to fabricate LPG sphere storage tank as per ASME SEC VIII Div 1 2010 Ed. with client data sheet and drawings. The design data is as follows: Des. pressure  (Int. & Ext.)  -     10.2 bar/FV Des  temperature                -       -42 degree C./+90 Degree C. MDMT                               -       - 42 degree C Heat treatment                   -       Nil Radiography                      -       100% Charpy impact test            -        yes. Material                            -        SA 516 Gr70 N Inside dia                          -        11250 mm Thickness                        -          27 mm

I would like to clarify :   1)  Why the heat treatment is not required since the impact test is there and thickness is above 16mm As per ASME code does not ask for PWHT but client spec ask for PWHt please confirm from client                            2)  Production test coupon for impact test is required or not as per code  OR can we exempt impact test with any of the code clauses UCS 66 and UG20. ( As the service/ design temp is of subzero temp hence PTC will be required to test for Impact at minus 42C

Please do reply. Thanks and Regards. Manoj

[Lalu r p]

Dear Friend 

                Impact test is to ensure that the toughness of the steel used for a particular item will be enough to avoid brittle fracture in service and they are tested at a temperature related to the designed temperature for the fabricated component.

[MM]

Dear Manoj,

 

PWHT for P1 material is must above 38mm, not required between 32 to 38mm if Preheated to 95°C during welding, less than that not required as per UCS 56,

However PWHT may be required due to service conditions or if you want  to take impact exceptions (e.g UCS 68(c )

 

Anyhow SA 516 Gr. 70 N (curve D) will qualify upto -43°C up to 17.5mm thickness (refer table UCS 66, fig UCS 66)

 

Refer UG 84 for PTC requirements..

 

Cheers

MM

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of manoj john
Sent: Tuesday, March 05, 2013 6:53 AM
To: material...@googlegroups.com
Subject: [MW:16941] IMPACT TESTING OF LPG STORAGE TANK

 

Dear Experts,

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