ASME BPVC 2023 Section VIII div. 1

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SUBSECTION C
REQUIREMENTS PERTAINING TO CLASSES OF
MATERIALS
PART UCS
REQUIREMENTS FOR PRESSURE VESSELS CONSTRUCTED OF
CARBON AND LOW ALLOY STEELS52
GENERAL
UCS-1 SCOPE
The rules in Part UCS are applicable to pressure vessels
and vessel parts that are constructed of carbon and low
alloy steels and shall be used in conjunction with the general
requirements in Subsection A, and with the specific
requirements in Subsection B that pertain to the method
of fabrication used.
MATERIALS
UCS-5 GENERAL
a All carbon and low alloy steel material subject to
stress due to pressure shall conform to one of the Specifications
given in Section II and shall be limited to those
listed in Table UCS-23 except as otherwise provided in
UG-10 and UG-11.
b In addition to the requirements of UG-4a, backing
strips which remain in place need not conform to a material
specification permitted by this Division if all of the following
are met:
1 The specification maximum composition limits or
certificate values for the backing strip material shall not
exceed those of the material specification for the pressure
part to which it is attached.
2 Either of the following requirements shall be met:
-a The backing strip base metal, and its associated
HAZ, and the weld metal shall be impact tested in
accordance with UG-84 at the MDMT shown on the nameplate
with a butt weld test specimen to the pressure part
material or to a material with the same PNo. and Group
No. as the pressure part.
-b The material is assigned to Curve A and is exempt
from impact testing at the MDMT shown on the
nameplate by Figure UCS-66 Figure UCS-66M alone
[i.e., MDMT reduction per Figure UCS-66.1 Figure
UCS-66.1M] is not permitted], and both of the following
apply:
-1 The backing strip material specification
minimum tensile strength shall not exceed that of the
pressure part material specification.
-2 The backing strip material specification
minimum percent elongation shall be at least equal to that
for the pressure part material specification.
c Carbon or low alloy steel having a carbon content of