Can we use the plate A283 Gr C instead of the S 275 Jr in storage tank shell repair? 3

[Youcef40]

Dear Gents,

A283 Grade C and S275JR are not directly interchangeable, but they are considered equivalent for certain applications. A283 Grade C is a carbon steel with good welding properties and economic usage, while S275JR is a structural steel widely used in the construction industry, manufacturing plants. The chemical and mechanical properties of these two materials have overlapping parts but also differences.
for our coming shutdown we need to repair and replace some Tank shell courses, and the only material we had is A283 Gr C. and the original ones are S275JR.
my question is can we use A283 instead of S275Jr in this repair?

 

[JStephen]

You would need to evaluate the original design conditions for the tank with respect to allowable stress and lowest design metal temperature.
Also see Section 5.6.1.3 of API-650.

 

[Youcef40]

Dear JStephen .

could you please give me more details .

 

[HTURKAK]

ENG.Youcef40 (Mechanical),

Probably you can use plate A283 Gr C instead of the S 275 Jr as long as existing tank material in the repair , Fall within the “safe for use” area on Figure 5.2. Exemption Curve , Stress in the repair area shall not exceed 7000 lbf/in.2. or meet the API 650 requirements.

My points ,

- Did you evaluate the shell acc. to clause 4.3 (Tank Shell Evaluation ) and decided that Shell Repair is necessary ?
- If yes , what kind of patch you are planning (Lap-welded Patch Plates )clause 9.3, or butt welded Replacement of Shell Plate Material as per clause 9.2 ?
- Can you post more info. ( size , design temperature, ambient temperature , content, age of the tank, the findings of shell evaluation.



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

NEW ENGLAND MAXIM

 

[IFRs]

I would spend less time comapring A283 to S275 and more time validating the suitability of A283 for your situation.

A283C is an API listed material so if it meets the required strength and toughness requirements of this tank's design, in my opinion you can use it. Just go through the API design process as if you were designing a new tank, including all load conditions, corrosion allowance, etc.

Also have a qualified weld procedure for joining the two materials.

This opinion is from the World's Wild Web.

 

[JStephen]

First off, I don't see S275Jr listed in API-650, and I'm not familiar with it. I do see some other S275 grades listed.
You mention "replacing" tank shell courses, which I understand to mean cutting an entire circle of shell plate out and replacing it with new plate. As opposed to patchwork repairs.
API-650 limits the lowest temperature that shell plates may be used at without impact testing. The application would either need to meet that exemption or you'd need to do impact testing to meet API-650 with the proposed material.
Then you need to calculate minimum thickness, based on API-650, for the new material, including any provisions for product stresses, wind, seismic, corrosion, etc.
If the calculations show that the new shell plate must be thicker than the existing shell thickness, then refer to the paragraph I referenced above, which limits when courses can be thicker than the course below.

Generally, if you're in a warm climate and the tank(s) are relatively small (as in, governed my minimum thickness rather than stress), these are going to be non-issues.
If you're in a cold climate and/or the tanks are large, then the situation may get more involved.

 

[Youcef40]

Gents,

hereunder some information about our Tank,

working capacity 207 m3
operating medium Aquifer Water
Operating Pressure (Bar) Atm.
Operating Temperature (°C) 5 to 50
Design Pressure (Bar) 0.02 to -0.005 bar
Design Temperature (°C) -5 / 93
Inner Diameter (mm)7000
Height (mm) 9840
Maximum Filling Height (mm)8580
Shell / bottom / roof Material BS EN 10025 S275 CS
Bottom thickness (mm) 6 mm
Shell courses (No.) thickness (mm)5 courses 4 x2000 mm height, the last one 1814 mm height, with thickness: 5mm
Roof Thickness (mm)8mm

the corrosion reports indicate 130 locations with sever corrosion and 164 mediums.

 

[HTURKAK]

ENG. Youcef40 (Mechanical),

Apparently the shell thk 5.0 mm is choosen as per min. thk. requirement. One foot method gives 2.6 mm thk. at the bottom course.
You did not supply any info. for the shell evaluation ( remaining thk.) etc. and age of the tank.

I will suggest you ,

- Conduct shell evaluation study and see if the remaining thk is OK for next service life. If the remaining thk is OK , remove the old paint with sand blasting and apply new paint. ( Epoxy based etc) and consider CP to extent service life.

- If the remaining thk. is not OK , 130 heavy corrosion location shall not be repaired with patching. Abandon the tank and construct new one with CP.





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

NEW ENGLAND MAXIM

 

[Youcef40]

Dear HTURKAK

for the remaining shell thickness, we found for shells 02 & 03 the minimum thicknesses 2.3mm, the bottom shell and the upper one shell 04 are good.
the year of construction 1999.