[Code of Federal Regulations]
[Title 46, Volume 2]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR54.25-10]
[Page 163-165]
TITLE 46--SHIPPING
CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)
PART 54_PRESSURE VESSELS--Table of Contents
Subpart 54.25_Construction With Carbon, Alloy, and Heat Treated Steels
Sec. 54.25-10 Low temperature operation--ferritic steels (replaces UCS-65
through UCS-67).
(a) Scope. (1) This section contains requirements for pressure
vessels and nonpressure vessel type tanks and associated secondary
barrier, as defined in Sec. 38.05-4 and Sec. 154.7 of this chapter,
and their parts constructed of carbon and alloy steels which are
stressed at operating or hydrostatic test temperatures below 0 [deg]F.
(2) The service temperature is the minimum temperature of a product
at which it may be contained, loaded and/or transported. However, the
service temperature shall in no case be taken higher than given by the
following formula:
ts=tw-0.25(tw-tB)
where:
ts=Service temperature.
tw=Boiling temperature of gas at normal working pressure of
container but not higher than +32 [deg]F.
tB=Boiling temperature of gas at atmospheric pressure.
Only temperatures due to refrigerated service usually need to be
considered in determining the service temperature, except pressure
vessel type cargo tanks operating at ambient temperatures must meet
paragraph (d) of this section. ``Refrigerated service'', as used in this
paragraph, means a service in which the temperature is controlled by the
process and not by atmospheric conditions.
[[Page 164]]
(b) Specifications. Materials used in the construction of vessels to
operate below 0 [deg]F. (but not below the designated minimum service
temperature) shall conform to a specification given in Table UCS-23 in
the ASME Code and the following additional requirements:
Note: For high alloy steels refer to Sec. 54.25-15. For heat
treated steels refer to Sec. 54.25-20.
(1)(i) For minimum service temperatures not lower than -67 [deg]F.,
ferritic steels shall be made with fine grain practice and shall have an
austenitic grain size of 5 or finer, and shall be normalized.
Consideration will be given to other heat treatments. Refer to Sec.
57.03-1(d) of this subchapter. Plate for pressure vessel applications
shall conform to the requirements of ASTM A 20 (incorporated by
reference, see Sec. 54.01-1). It may be produced by the open hearth,
basic oxygen or electric furnace process and shall conform to the
requirements of Table 54.25-10(b)(1). (Other alloying elements may only
be present in trace amounts.)
(ii) Mechanical properties shall be within the following limits:
Ultimate strength........................ --58,000 \1\-85,000 \1\
p.s.i.
Yield strength........................... --Minimum 35,000 p.s.i.
--Maximum 80 percent of
ultimate.
Elongation minimum....................... --20 percent in 8 inches, or
--24 percent in 2 inches, or
--22 percent in 5.65
A, where ``A'' is
the test specimen cross
sectional area.
Table 54.25-10(b)(1)
------------------------------------------------------------------------
Manganese
Minimum service \1\ temperature [deg]F Max. C \1\ range \1\
percent percent
------------------------------------------------------------------------
-30........................................... 0.20 0.70-1.35
-50........................................... .16 1.15-1.50
-67........................................... .12 1.30-1.60
------------------------------------------------------------------------
\1\ At service temperatures intermediate between those specified,
intermediate amounts of carbon and manganese will be allowed (in
proportion to the actual service temperature variation from that
listed), provided all other chemical and mechanical properties
specified for steels in this temperature range are satisfied.
Range
percent
Si.......................................................... 0.10-0.50
Maximum
S........................................................... 0.035
P........................................................... 0.035
Ni.......................................................... 0.80
Cr.......................................................... 0.25
Mo.......................................................... 0.08
Cu.......................................................... 0.035
Nb.......................................................... 0.05
V........................................................... 0.08
(2) For minimum service temperature below -67 [deg]F., but not below
the designated minimum service temperature, ferritic steels shall be
normalized, low carbon, fully killed, fine grain, nickel alloy type,
conforming to any one of the specifications in Table 54.25-10(b)(2).
Consideration will be given to other heat treatments. Refer to Sec.
57.03-1(d) of this subchapter for quenched and tempered steels. The
ultimate and yield strengths shall be as shown in the applicable
specification and shall be suitable to the design stress levels adopted.
The service temperature shall not be colder than the minimum specified
in Table 54.25-10(b)(2) for each steel.
Table 54.25-10(b)(2)
------------------------------------------------------------------------
Steel Minimum service temperature
------------------------------------------------------------------------
A-203, 2\1/4\ percent, Ni, normalized.... -80 [deg]F. for Grade A.
-75 [deg]F. for Grade B.
A-203, 3\1/2\ percent, Ni, normalized.... -130 [deg]F. for Grade D.
-110 [deg]F. for Grade E.
5 percent Ni, normalized................. Dependent on chemical and
physical properties.
------------------------------------------------------------------------
(3) The materials permitted under paragraphs (b) (1) and (2) of this
section shall be tested for toughness in accordance with and shall
satisfy the applicable requirements of subpart 54.05.
(4) Welded pressure vessels or nonpressure vessel type tanks and
associated secondary barriers, as defined in Sec. 38.05-4 of subchapter
D (Tank Vessels) of this chapter shall meet the toughness requirements
of subparts 57.03 and 57.06 of this subchapter with regard to weld
procedure qualifications and production testing.
(5) The material manufacturer's identification marking required by
the material specification shall not be die-stamped on plate material
less than one-fourth inch in thickness.
(c) Design. Pressure vessels must meet the requirements for Class I-
L and II-L construction. (See Table 54.01-5(b) for applicable
requirements). Except as permitted by Sec. 54.05-30, the allowable
stress values used in the design of low temperature pressure vessels may
not exceed those given in Table UCS-23 of the ASME Code for temperatures
of 0 [deg]F. to 650 [deg]F. For materials not listed in this Table
allowable stress values are determined in accordance
[[Page 165]]
with Appendix P of Section VIII of the ASME Code.
(d) Weldments and all materials used in pressure vessel type cargo
tanks operating at ambient temperatures and constructed of materials
listed in Table UCS-23 must pass Charpy impact tests in accordance with
UG-84 at a temperature of -20 [deg]F or colder, except as provided by
paragraphs (d)(1), (d)(2), and (d)(3) of this section.
(1) Charpy impact tests are not required for any of the following
ASTM materials if the thickness for each is \5/8\ inch or less, unless
otherwise indicated:
(i) A-182, normalized and tempered.
(ii) A-302, Grades C and D.
(iii) A-336, Grades F21 and F22 that are normalized and tempered.
(iv) A-387, Grades 21 and 22 that are normalized and tempered.
(v) A-516, Grades 55 and 60.
(vi) A-533, Grades B and C.
(vii) All other plates, structural shapes and bars, and other
product forms, except for bolting, if produced to a fine grain practice
and normalized.
(2) Charpy impact tests are not required for any of the following
ASTM materials if the thickness for each is 1\1/4\ inch or less:
(i) A-203.
(ii) A-508, Class 1.
(iii) A-516, normalized.
(iv) A-524.
(v) A-537.
(vi) A-612, normalized.
(vii) A-662, normalized.
(viii) A-724, normalized.
(3) Charpy impact tests are not required for any of the following
bolt materials:
(i) A-193, Grades B5, B7, B7M, and B16.
(ii) A-307, Grade B
(iii) A-325, Type 1.
(iv) A-449.
[CGFR 68-82, 33 FR 18828, Dec. 18, 1968, as amended by CGFR 69-127, 35
FR 9977, June 17, 1970; CGD 73-133R, 39 FR 9178, Mar. 8, 1974; CGD 74-
289, 44 FR 26007, May 3, 1979; CGD 77-069, 52 FR 31626, Aug. 21, 1987;
CGD 85-061, 54 FR 50964, Dec. 11, 1989; USCG-1999-5151, 64 FR 67178,
Dec. 1, 1999; USCG-2000-7790, 65 FR 58460, Sept. 29, 2000]