Page 102 - Pressure Vessel Design Manual

General Design 83

0 20 40 60 80 100 120 140
"F ("C) [See UCS-66(b)]
Nomenclature (Note reference to General Notes of Fig. UCS-66-2.)
lr= required thickness of the component under consideration in the corroded Nominal Thickness, in (mm)
condition for all applicable loadings [General Note (Z)], based on the
applicable joint efficiency €[General Note (3)]. in. (mm) [Limited lo 4 in (102 mm) for Welded Construction]
1" = nominal thickness of the component under consideration before corrosion
allowance is deducted, in. (mm) Figure 2-55. Impact test exemption curves.
c = corrosion allowance, in. (mm)
E' =as defined in General Note (3).
Alternative Ratio = S'E'divided by the product of the maximum allowable stress value
from Table UCS-23 times E. where S'is the applied general
primary membrane tensile Stress and Eand E'are as defined in General
Note (3)
Figure 2-54. Reduction in minimum design metal temperature without SA-51 6 if normalized
impact testing. SA-524 Classes 1 and 2
SA-537 Classes 1 and 2
SA-61 2 if normalized
General Notes on Assignment of Materials to Curves (Reprinted SA-622 if normalized
with permission from ASME Code, Section VIII, Div. 1.) e. For bolting the following impact test exemption temperature shall
a. Curve A-all carbon and all low alloy steel plates, structural
shapes, and bars not listed in Curves B, C, and D below. apply:
b. CurveB
1. SA-285 Grades A and B Impact Test
SA-414 Grade A Spec. No. Grade Exemption Temperature, F
SA-515 Grades 55 and 60 SA-193 B5 -20
SA-516 Grades 65 and 70 if not normalized SA-193 B7 -40
SA-612 if not normalized SA-193 B7M -50
SA-662 Grade B if not normalized
2. all materials of Curve A if produced to fine grain practice and SA-193 B16 -20
normalized which are not listed for Curves C and D below. SA-307 B -20
3. except for bolting (see (e) below), plates, structural shapes, and SA-320 B L7, L7A, Impact tested
bars, all other product forms (such as pipe, fittings, forgings, L7M, L43
castings, and tubing) not listed for Curves C and D below. SA-325 1, 2 -20
4. parts permitted under UG-11 shall be included in Curve B even SA-354 BC 0
when fabricated from plate that otherwise would be assigned to SA-354 BD +20
a different curve. SA-449 __. -20
c. CurveC SA-540 823124 +10
1. SA-1 82 Grades 21 and 22 if normalized and tempered
SA-302 Grades C and D
SA-336 Grades F21 and F22 if normalized and tempered
SA-387 Grades 21 and 22 if normalized and tempered f. When no class or grade is shown, all classes or grades are
SA-516 Grades 55 and 60 if not normalized included.
SA-533 Grades B and C g. The following shall apply to all material assignment notes:
SA-662 Grade A 1. Cooling rates faster than those obtained by cooling in air, fol-
2. all material of Curve B if produced to fine grain practice and lowed by tempering, as permitted by the material specification,
normalized and not listed for Curve D below. are considered to be equivalent to normalizing or normalizing
d. CurveD and tempering heat treatments.
SA-203 2. Fine grain practice is defined as the procedures necessary to
SA-508 Class 1 obtain a fine austenitic grain size as described in SA-20.