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 °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.
Note: For high alloy steels refer to § 54.25-15 . For heat treated steels refer to § 54.25-20 .
Ultimate strength | -58,0001-85,0001 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 [RADIC]A, where "A" is the test specimen cross sectional area. |
Table 54.25-10(b)(1)
Minimum service1 temperature °F | Max. C1 percent | Manganese range1 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 |
Table 54.25-10(b)(2)
Steel | Minimum service temperature |
A-203, 21/4 percent, Ni, normalized | -80 °F. for Grade A. -75 °F. for Grade B. |
A-203, 31/2 percent, Ni, normalized | -130 °F. for Grade D. -110 °F. for Grade E. |
5 percent Ni, normalized | Dependent on chemical and physical properties. |
46 C.F.R. §54.25-10