flat and flange head only (asme code)

[apooyana]

Hello everybody,

we produced a dished only head as tube plate of a fire tube boiler with cold forming, but there is a thickness reduction of about 3 mm at the knuckle ,after forming (before forming thickness =25 mm).
now the question: if the minimum thickness required on the flat part of tube plate is 24.5 per code (for example) , what do you think about this value of knuckle reduction thk.
I think because of the low radius of this part (about 75 mm) , thk. 25-3=22 mm is ok about strength. what do you think.
thanks

 

[Don56]

What design code are you using? ASME Section VIII has calculation for minimum thickness for a formed head. I think you need to calculate the minimum required thickness necessary.

 

[racookpe1978]

24.5 minimum thickness? Or 1 inch = 25.4 mm?

Minimum thickness is NEVER " is ok about strength". It must be calculated, then verified as-built greater than minimum (for corrosion allowance, construction margin, etc.)

 

[apooyana]

Don56 , thank you
The code is EN-52193 , AND THE HEAD IS NOT UNSUPPORTED(WE SUPPORT TUBE PLATE BY SOME STAYS). SO WE CAN'T CALCULATE BY THE CODE AS A WHOLE.

 

[apooyana]

THANKS racookpe1978
BY THE 24.5 I MEANT MINIMUM REQUIRED THICKNESS (AFTER TAKING CORROSION AND RELATED ALLOWANCES)FOR FLAT PORTION,BUT I DON'T KNOW ABOUT KNUCKLE PART.HOW CAN I CALCULATE THAT PORTION .