API 653 - Shell repairs by deposition of weld metal 1

[sajk14]

Hello All,

API 653 section 9.4 states that the shell can be repaired by 'deposition of weld metal'.

My query is that if weld deposition repairs are carried out on the shell, what rules should be used with regards to minimum weld spacing requirements?

I would typically use the guidance shown in Figure 9.1 in API 653. However someone has challenged me on this stating that Fig 9.1 only applies to shell insert plate repairs or shell patch plate repairs, therefore we don't need to apply these rules as API 653 does not specifically refer you to Fig 9.1 for weld deposition repairs.

The location of the first weld overlay repair is just above the 'shell to bottom' connection and the other is located right next to a vertical shell butt joint.

I would appreciate your thoughts and opinions on the above.

Many Thanks

 

[HTURKAK]

My points ,

- Figure 9.1 is Replacement of Shell Plate Material, Acceptable Details.
- Clause 9.4 Repair of Defects in Shell Plate Material is self explanatory.

... In areas where the shell plate thickness exceeds that required by design conditions, it is permissible to grind surface irregularities to a smooth contour so long as the remaining thickness is adequate for the design conditions. Where grinding to a smoothly contoured surface will result in unacceptable shell plate metal thickness, the shell plate may be repaired by deposition of weld metal..



Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM

 

[sajk14]

Thanks HTURKAK,

My query was not really about an explanation of clause 9.4 and weld deposition repairs but rather what rules/guidance should be used for the minimum clearance between a main tank shell joint and a weld deposition repair.

 

[Dhurjati Sen]

Since a weld build up is just restoring the plates to their original thickness, it has no connection with the weld joints of the tank.
However, care should be taken to ensure that weld build ups are done by qualified welders and those locations are to be LPI tested as a best practice. The weld build up process should not lead to any weld defects on the existing weld joints like arc strike, etc

DHURJATI SEN
Kolkata, India

 

[HTURKAK]

Mr . Dhurjati Sen ,
Your comment is excellent and a PBS for your post....

Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM