Selection of Plate material

[Pipingclassic]

Hi Friends,
We have plate material available for Pressure vessel and spectacle blinds as A515 and A516 and in that we have several grades like in A516 we have 55, 60, 70. I want to use this plate material for spectacle blinds for 51.1barg pressure and 427 deg. temp.

Anyone can suggest the basis for selecting the grade.

Thanks

 

[weldstan]

Any of the specifications and grades may be used. Base your selection on price - plate thickness required, and availability thereof with materials at hand.

 

[metengr]

Not being a big fan of the weldability issues associated with SA 515 grades of plate steels, I would use SA-516 plate material.

 

[metengr]

weldability

, should be notch toughness. A senior moment.

 

[TomEun]

You may have to consider the following three points (other than material cost). Basically the temperature condition should be clearly confirmed.

1. Graphitization
If the 427C is based on the nommal operating condition, the material should be upgraded to Cr-Mo steel (e.g., 1-1.25Cr-0.5Mo steel) to avoid graphitization.
(See API 579-1/ASME FFS-1)

2. Creep-Rupture
If the nommal operating temperature is above 370C, the material will be exposed to creep zone. In this case, A515 which has a large grain size is preferable.

3. Welding
Once it is non-weldable material (e.g., Blind), the higher tensile strength is better. If it is weldable component in non-corrosion cracking environment, Gr.70 is preferable. However, if it is weldable component in corrosion cracking environment, Gr.60-65 is preferable.

Hope this helps,

Thomas Eun

 

[weldstan]

Please note that I assumed 427F. If 427C, see TomEun.

 

[Pipingclassic]

Thanks all...Mr. Thomas I agree with you...

The design temp. is 427 deg C