Extream Fiber elongation is more than 5%

[tananT]

For P-No. 1 Group Nos. 1 and 2 materials the extreme
fiber elongation may be as great as 40% when none
of the conditions listed below in (1) through (5) exist.
(1) The vessel will contain lethal substances either
liquid or gaseous (see UW-2).
(2) The material requires impact testing.
(3) The thickness of the part before cold forming
exceeds 5?8 in. (16 mm).
(4) The reduction by cold forming from the as rolled
thickness is more than 10%.
(5) The temperature of the material during forming
is in the range of 250°F to 900°F (121°C to 482°C).

I would like to know about item No.4. how to check and how to calculation?

thank you all for kindly

 

[metengr]

tananT;
If you review the 2007 edition of ASME B&PV Code, Section VIII, Div 1 UCS-79, subparagraph (4) reads…. the reduction by cold forming from the as-rolled thickness is more than 10% at any location where the extreme fiber elongation exceeds 5%.

This means if you add a step of cold forming that result in a wall thickness reduction of greater than 10% from the original supplied wall thickness in the location where the extreme fiber elongation was greater than 5%, you must conduct a thermal heat treatment after forming.

 

[Shmulik]

I would say that calculation is about to be done by Poisson's Ratio

http://www.efunda.com/formulae/solid_mechanics/mat_mechanics/elastic_constants_E_nu.cfm

http://www.engineeringtoolbox.com/poissons-ratio-d_1224.html

http://www.diracdelta.co.uk/science/source/p/o/poissons ratio/source.html