welding of different steel quality

[deepack]

Hi,

Is it okey to use P460NH (endcaps) with P460NL (shell) and weld them together?
They are pretty much the same, but NH is for elevated temperatures, and NL is for low temperatures.

Also what MMA electrodes is recommended for this?
Got recommended on the OK 48.15, but not entirely sure on this.

Thank you very much.

-deepack

 

[metengr]

Weldability looks good for these two grades. The Ok48.15 looks acceptable based on the ESAB weld product specification. The P460NH and NL grades are low alloy carbon steel grades and are similar, with the exception of fine grained versus elevated temperature strength. Do you have a welding rocedure qualified for these two materials?

 

[deepack]

Thank you for your answer. Will P460NL be a stronger material for use in 0 degree celsius temperature?

I don`t have a welding procedure for these materials? Where can I find one?

Thanks
-deepack

 

[metengr]

The NL grade should have better notch toughness versus the NH grade. But at 0 deg C both steels should be acceptable. As far as a welding procedure, you need to qualify it based on either AWS or ASME B&PV Code (Section IX).

 

[deepack]

But notch toughness won`t be an issue in a pressure vessel?

thanks
-deepack

 

[metengr]

It can be, indeed. You seem to be way over your head in this area.

 

[weldstan]

Deepak,
You need to define the Design/Construction Code. ASME VIII? European Code with Pressure Directive? Thickness? Minimum Design Metal Temperature?