Impact test requirement

[vessexst]

Hi all,

I have a vessel, having an MDMT of -44 Deg C. I am using SA 516 70 for shell and heads. The design pressure is 98 bars at which the thickness of shell and heads is coming as 106mm. Since, the impact test is mandatory, should I ask the vendor to take normalized material or is there no requirement of normalizing the material since it is to be impact tested?

 

[david339933]

Read SA-516-70, heat treat requirements....take note of the thicknesses.
This is kind of an easy question, considering you are building a vessel over 4" thick.

 

[vessexst]

@david339933: I know it is an easy question. But the thing I am confused is the impact test. Normally, I would go for a normalized material to avoid impact test requirement. But, since, in this case, impact test cannot be avoided owing to thickness greater than 4 inch, I am confused if i should also mention normalizing requirement since the material is to be impact tested any way

 

[david339933]

Easy question yes.....IF you read the spec.....plates over 1.5" "shall be normalized". You don't have a choice.

 

Normalizing is mandatory for SA-516 above 1.5" thick.
-44°C is pushing it for SA 516-70, especially at that thickness. You may want to reconsider.
If I were buying this material I would insist on traceability to a reputable mill, with restrictions on impurities (P, S) and a maximum on C.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[vessexst]

Thanku all of you for your help. I understand it was a pretty simple question.
And one more thing, is there any way you can specify a normalized material for nozzle on pv elite??
There is a 24" manway on a 1200 mm ID vessel. The shell thickness is 32 mm. The manway is rolled to 24" from sa 516 70 plate. The reqd thickness of pad is coming as 34 mm and nozzle neck as 32 mm.
At these dimensions, the mdmt comes as +4. The required is -5.
Is there any way a normalized material can be specified for manway neck and nozzle

 

[r6155]

vessexst:
1) Read ASME code
2) Do calculations by hand
3) Use PV-elite or similar
4) Again, read ASME code

Regards

 

[weldstan]

The manufacturer will no doubt add accelerated cooling from the normalizing temp to achieve impact properties at the thickness. You will no doubt require SA-350 LF2 for the forged fittings which will no doubt be quenched and tempered.

 

Manways from rolled plate? Consider instead SA-350 LF2 or SA-508 Grade 1 forgings. Forgings are more cost-effective if they eliminate even one weld.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."