UCS-79d interpretation

[b20vtechb]

i'm having a little bit of trouble coming to a correct understanding of this section of code.

in section ucs-79d it states

(d) Vessel shell sections, heads, and other pressure
boundary parts of carbon and low alloy steel plates fabricated
by cold forming shall be heat treated subsequently
(see UCS-56) when the resulting extreme fiber elongation
is more than 5% from the as-rolled condition and any of
the following conditions 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% at any location where the
extreme fiber elongation exceeds 5%.
(5) The temperature of the material during forming
is in the range of 250°F to 900°F (120°C to 480°C).


what i am not sure about is the meaning of "as rolled condition"

i have a head that has an extreme fiber elongation of 9.375% and condition 4 of the code will almost always be in effect because it is a spun part.
The material its self has an elongation of 27% acording to the material cert.
so i guess my question is does my elongation on the head need to be 5% higher then 27% to require heat treat under this code?

 

[metengr]

The elongation on the material cert is from tensile testing for mechanical properties - UTS, YS and percent elongation. The fiber elongation is tensile strain induced from cold or warm forming only. So, you have a plate received that has been rolled from the mill. This is your starting point for measuring additional fiber elongation IF further work is performed from processing. If you exceed 5% fiber elongation, the material must be subjected to thermal treatment to relieve forming strains.