Elongation in plate rolling process 2

[Faiz vhora]

Elongation in plate rolling process in pressure vessel manufacturing

They are telling me (in the workshop) that if they cut the plate length based on the mean radius, there will be some extra length after rolling. Is there a formula or a reference to estimate that?

I want to know how to calculate exact length of a plate before rolling to a specified diameter.
Does it depend on the material being rolled? (say Carbon steel or Stainless steel)
Does it depend on the thickness of the plate?
How about the rolling equipment or even the operator of that equipment(the technique)?
Tell me the formula that used to determine elongation for a mild steel material.


Warm Regards

 

[r6155]

See formula in ROARK´S
"distance from centroidal axis to neutral axis measured toward center of curvature"

Regards

 

[Faiz vhora]

Thank you for your reply.Can you please tell me the page or attach a picture of that?

 

[r6155]

Try to put minimal effort yourself.
Regards

 

[Faiz vhora]

Yes i have put an effort but can't able to find the formula which i am looking for.
Elongation in rolling process mild steel material can we find it by FL/AE ?

 

[r6155]

Search in pdf "distance from centroidal axis to neutral axis measured toward center of curvature"

 

[Faiz vhora]

Ok thanks.

 

[austsa]

The amount of extra length depends on a number of factors, including the roller machine design. Smaller machines would need less extra length (say +300mm, but smaller machines would only be able to roll short widths). Larger machines would need more extra length (say +600mm). Extra length gets trimmed off by the workshop.

 

[Faiz vhora]

Yaa exactly that's what i am asking for is there any specific formula? Yes or no ? And if yes what is it!?

 

[r6155]

@ austsa
The (OP) needs the length of plate (NOT THE ELONGATION) before rolling to the desired diameter, not the extra length.
Several fabricators preform both ends of the plate with a press, with the exact length of plate to the desired diameter.
Several rolling machines do not need extra length of plate.

@ Faiz vhora
The elongation (you don´t need it)is 1,96%.
See ASME VIII Div 1

Regards

 

[JStephen]

It would take a little work to confirm, but reference is made to the shift of the neutral axis for a curved beam. If I'm not mistaken, the information referenced there is for the shift when an initially curved beam is bent elastically, but would not apply when an initially straight beam is rolled into a curved shape with extensive yielding.

 

[r6155]

@ JStephen
If I have a bent beam, the displacement of the neutral axis is of no use. It is used prior to bending.

Regards